| 1. |
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| 2. |
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| 3. |
- Abermann, S., et al.
(författare)
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Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric
- 2007
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 84:5-8, s. 1635-1638
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate various metal gate/high-k/Si capacitors by their resulting electrical characteristics. Therefore, we process MOS gate stacks incorporating aluminium (Al), nickel (Ni), titanium-nitride (TiN), and molybdenum (Mo) as the gate material, and metal organic chemical vapour deposited (MOCVD) ZrO2 and HfO2 as the gate dielectric, respectively. The influence of the processing sequence - especially of the thermal annealing treatment - on the electrical characteristics of the various gate stacks is being investigated. Whereas post metallization annealing in forming gas atmosphere improves capacitance-voltage behaviour (due to reduced interface-, and oxide charge density), current-voltage characteristics degrade due to a higher leakage current after thermal treatment at higher temperatures. The Flatband-voltage values for the TiN-, Mo-, and Ni-capacitors indicate mid-gap pinning of the metal gates, however, Ni seems to be thermally unstable on ZrO2, at least within the process scheme we applied.
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| 4. |
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| 5. |
- Ahlberg, Patrik, et al.
(författare)
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A two-in-one process for reliable graphene transistors processed with photolithography
- 2015
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:20
-
Tidskriftsartikel (refereegranskat)abstract
- Research on graphene field-effect transistors (GFETs) has mainly relied on devices fabricated using electron-beam lithography for pattern generation, a method that has known problems with polymer contaminants. GFETs fabricated via photo-lithography suffer even worse from other chemical contaminations, which may lead to strong unintentional doping of the graphene. In this letter, we report on a scalable fabrication process for reliable GFETs based on ordinary photo-lithography by eliminating the aforementioned issues. The key to making this GFET processing compatible with silicon technology lies in a two-in-one process where a gate dielectric is deposited by means of atomic layer deposition. During this deposition step, contaminants, likely unintentionally introduced during the graphene transfer and patterning, are effectively removed. The resulting GFETs exhibit current-voltage characteristics representative to that of intrinsic non-doped graphene. Fundamental aspects pertaining to the surface engineering employed in this work are investigated in the light of chemical analysis in combination with electrical characterization.
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| 6. |
- Ahlberg, Patrik, 1985-, et al.
(författare)
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Interface Dependent Effective Mobility in Graphene Field Effect Transistors
- 2018
-
Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 47:3, s. 1757-1761
-
Tidskriftsartikel (refereegranskat)abstract
- By pretreating the substrate of a graphene field-effect transistor (G-FET), a stable unipolar transfer characteristic, instead of the typical V-shape ambipolar behavior, has been demonstrated. This behavior is achieved through functionalization of the SiO2/Si substrate that changes the SiO2 surface from hydrophilic to hydrophobic, in combination with postdeposition of an Al2O3 film by atomic layer deposition (ALD). Consequently, the back-gated G-FET is found to have increased apparent hole mobility and suppressed apparent electron mobility. Furthermore, with addition of a top-gate electrode, the G-FET is in a double-gate configuration with independent top- or back-gate control. The observed difference in mobility is shown to also be dependent on the top-gate bias, with more pronounced effect at higher electric field. Thus, the combination of top and bottom gates allows control of the G-FET's electron and hole mobilities, i.e., of the transfer behavior. Based on these observations, it is proposed that polar ligands are introduced during the ALD step and, depending on their polarization, result in an apparent increase of the effective hole mobility and an apparent suppressed effective electron mobility.
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| 7. |
- Andersson, Per, et al.
(författare)
-
Utbildningsinsats för att höja den pedagogiska digitala kompetensen
- 2016
-
Konferensbidrag (refereegranskat)abstract
- Under 2015 genomförde Medicinska fakulteten vid Umeå universitet en satsning för att höja den Pedagogiska Digitala Kompetensen (PDK) bland sina medarbetare i syfte att öka de digitala inslagen i undervisningen. En del i satsningen var att genomföra en utbildningsinsats. Uppdraget gavs till Pedagogiska institutionen som i samarbete med Universitetspedagogik och lärandestöd (UPL) genomförde ett antal seminarier under 2015. Deltagarna hade möjlighet att delta på plats i Umeå eller via nätet. Målsättningen var att varje seminarium skulle innehålla både teoretiska och praktiska inslag och en progression från inledande förmedlande information till allt fler deltagaraktiva inslag. Under hösten 2015 genomfördes även en workshop, som utgjorde en fördjupning där deltagarna med utgångspunkt i en fiktiv kursplan samt metoden flipped classroom utarbetade egna förslag till kursdesign och undervisningsaktiviteter med stöd av digital teknik. Exempel på digital teknik som deltagarna har fått ta del av eller själva arbeta med under utbildningsinsatsen är Moodle, Googleapps, Adobe connect, Socrative, Screen cast-o-matic och Prezi. En webbresurs har funnits tillgänglig som komplement till seminarieserien. Där har deltagarna haft tillgång till instruktioner, frågeställningar, föreläsningsfilmer samt de digitala presentationerna som hållits under seminarierna. Utöver detta har även ett s.k. bonusmaterial i form av länkar och frivilliga uppgifter tillhandahållits för de som varit intresserade att fördjupa sig inom exempelvis e-lärande i relation till pedagogisk meritering. Totalt medverkade ca 100 deltagare, som representerade 20 utbildningsprogram på fakulteten, i utbildningsinsatsen. Utvärderingen av insatsen visar att majoriteten av deltagare upplever att de höjt sin pedagogiska digitala kompetens i hög eller mycket hög utsträckning. De uttrycker även att de tillägnat sig generella kunskaper, vilket ses som en viktig grund för det egna arbetet med att öka de digitala inslagen i undervisningen. En annan framträdande synpunkt är att de praktiska och exemplifierande inslagen har uppfattats som betydligt mer värdefulla från ett lärandeperspektiv än de inledande teoretiskt inriktade inslagen. Resultatet visar också att majoriteten anser att de ökat sina kunskaper om digitala resurser och verktyg som kan användas i undervisningen. Även webbresursen har använts flitigt. Utvärderingen visar att majoriteten anser att webbresursen varit ett bra komplement till seminarieserien. Detta återspeglas också i de loggdata som visar på relativt omfattande besöksfrekvenser. Att seminariematerialet fanns samlat på ett ställe och tillgängligt för deltagarna före och efter seminarierna har haft stor betydelse för deltagarna. Därmed underlättades deras förberedelser inför seminarierna och möjligheten gavs att i efterhand repetera och ytterligare fördjupa sina kunskaper.Sammanfattningsvis visar resultaten från utvärderingen att målen med utbildningsinsatsen uppnåtts på ett tillfredsställande sätt, och att satsningen sålunda fallit väl ut. En aspekt som inte framkommit ovan men som är värd att lyftas fram är det faktum att ett flertal kommentarer i utvärderingarna handlar om ett ökande intresse för, och en ökande nyfikenhet på, att integrera digitala inslag i sin egen undervisningspraktik i större utsträckning än tidigare. Den samlade bedömningen är att Medicinsk fakultet vid Umeå universitet i och med denna satsning lagt en mycket god grund för fortsatta utvecklingsarbeten avseende PDK.
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| 8. |
- Andersson, Per, et al.
(författare)
-
Utbildningsinsats för att höja den pedagogiskt digitala kompetensen
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Under 2015 genomförde Medicinska fakulteten vid Umeå universitet en satsning för att höja den Pedagogiska Digitala Kompetensen (PDK) bland sina medarbetare i syfte att öka de digitala inslagen i undervisningen. En del i satsningen var att genomföra en utbildningsinsats. Uppdraget gavs till Pedagogiska institutionen som i samarbete med Universitetspedagogik och lärandestöd (UPL) genomförde ett antal seminarier under 2015. Deltagarna hade möjlighet att delta på plats i Umeå eller via nätet. Målsättningen var att varje seminarium skulle innehålla både teoretiska och praktiska inslag och en progression från inledande förmedlande information till allt fler deltagaraktiva inslag. Under hösten 2015 genomfördes även en workshop, som utgjorde en fördjupning där deltagarna med utgångspunkt i en fiktiv kursplan samt metoden flipped classroom utarbetade egna förslag till kursdesign och undervisningsaktiviteter med stöd av digital teknik. Exempel på digital teknik som deltagarna har fått ta del av eller själva arbeta med under utbildningsinsatsen är Moodle, Googleapps, Adobe connect, Socrative, Screen cast-o-matic och Prezi.En webbresurs har funnits tillgänglig som komplement till seminarieserien. Där har deltagarna haft tillgång till instruktioner, frågeställningar, föreläsningsfilmer samt de digitala presentationerna som hållits under seminarierna. Utöver detta har även ett s.k. bonusmaterial i form av länkar och frivilliga uppgifter tillhandahållits för de som varit intresserade att fördjupa sig inom exempelvis e-lärande i relation till pedagogisk meritering.Totalt medverkade ca 100 deltagare, som representerade 20 utbildningsprogram på fakulteten, i utbildningsinsatsen. Utvärderingen av insatsen visar att majoriteten av deltagare upplever att de höjt sin pedagogiska digitala kompetens i hög eller mycket hög utsträckning. De uttrycker även att de tillägnat sig generella kunskaper, vilket ses som en viktig grund för det egna arbetet med att öka de digitala inslagen i undervisningen. En annan framträdande synpunkt är att de praktiska och exemplifierande inslagen har uppfattats som betydligt mer värdefulla från ett lärandeperspektiv än de inledande teoretiskt inriktade inslagen. Resultatet visar också att majoriteten anser att de ökat sina kunskaper om digitala resurser och verktyg som kan användas i undervisningen.Även webbresursen har använts flitigt. Utvärderingen visar att majoriteten anser att webbresursen varit ett bra komplement till seminarieserien. Detta återspeglas också i de loggdata som visar på relativt omfattande besöksfrekvenser. Att seminariematerialet fanns samlat på ett ställe och tillgängligt för deltagarna före och efter seminarierna har haft stor betydelse för deltagarna. Därmed underlättades deras förberedelser inför seminarierna och möjligheten gavs att i efterhand repetera och ytterligare fördjupa sina kunskaper.Sammanfattningsvis visar resultaten från utvärderingen att målen med utbildningsinsatsen uppnåtts på ett tillfredsställande sätt, och att satsningen sålunda fallit väl ut. En aspekt som inte framkommit ovan men som är värd att lyftas fram är det faktum att ett flertal kommentarer i utvärderingarna handlar om ett ökande intresse för, och en ökande nyfikenhet på, att integrera digitala inslag i sin egen undervisningspraktik i större utsträckning än tidigare. Den samlade bedömningen är att Medicinsk fakultet vid Umeå universitet i och med denna satsning lagt en mycket god grund för fortsatta utvecklingsarbeten avseende PDK.
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| 9. |
- Ankarcrona, Johan, et al.
(författare)
-
Simulation and modeling of the substrate contribution to the output resistance for RF-LDMOS power transistors
- 2004
-
Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 48:5, s. 789-797
-
Tidskriftsartikel (refereegranskat)abstract
- High frequency substrate losses for RF MOSFETs are analyzed using numerical device simulation. The results show that losses in devices made on low resistivity substrate occur through the substrate while losses in devices made on high resistivity substrate in the high frequency region occur along the surface through the device (source–drain). An equivalent circuit model is developed which accurately describes the off-state losses. Based on the model significant improvements in terms of output resistance are demonstrated, using an improved device on high resistivity substrate.
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| 10. |
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| 11. |
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| 12. |
- Chen, Xiangrong, 1982, et al.
(författare)
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Electrical Treeing Behavior of DC and Thermally Aged Polyethylenes Utilizing Wire-Plane Electrode Geometries
- 2014
-
Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - 1558-4135 .- 1070-9878. ; 21:1, s. 42-52
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents electrical treeing behavior in low density polyethylene (LDPE) and cross-linked polyethylene (XLPE) after exposure to thermal and DC electro-thermal ageing. Both the ageing and the treeing tests were performed by means of two different types of test objects with wire-plane electrode geometry. One type of the tested objects contained only wire electrode of 10 µm diameter, whereas in the other type the wire electrode was attached through a semiconducting tab. The ageing was performed at 80°C with and without 10 kV DC voltage of both polarities connected to the wire and lasted up to 800 hours. The AC electrical treeing tests were applied afterwards for detecting changes of material properties after the ageing. The results showed that the electrical tree inception voltage consistently decreased with increasing time of thermal exposure, whereas the applied DC electric stress had a negligible effect on the observed behavior. Similar effects were found in both the tested materials (LDPE and XLPE) though the object type also influenced the results. For the objects with semiconducting tab, a higher level of the scale parameter was registered because of shielding effect of the tab on the electric field strength at the wire electrode. It also yielded less number of trees growing in parallel at the electrode. The dominant effect of thermal stress on the ageing of LDPE was elucidated by using various analytical techniques, like differential scanning calorimetry, infrared spectroscopy, inductively coupled plasma optical emission spectrometry and oxidation induction time, and it is believed to mainly affect antioxidant content in the test objects.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Elgqvist, Jörgen, 1963, et al.
(författare)
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Administered activity and metastatic cure probability during radioimmunotherapy of ovarian cancer in nude mice with 211At-MX35 F(ab')2.
- 2006
-
Ingår i: International journal of radiation oncology, biology, physics. - : Elsevier BV. - 1879-355X .- 0360-3016. ; 66:4, s. 1228-37
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To elucidate the therapeutic efficacy of alpha-radioimmunotherapy of ovarian cancer in mice. This study: (i) estimated the minimum required activity (MRA), giving a reasonable high therapeutic efficacy; and (ii) calculated the specific energy to tumor cell nuclei and the metastatic cure probability (MCP) using various assumptions regarding monoclonal-antibody (mAb) distribution in measured tumors. The study was performed using the alpha-particle emitter Astatine-211 (211At) labeled to the mAb MX35 F(ab')2. METHODS AND MATERIALS: Animals were inoculated intraperitoneally with approximately 1 x 10(7) cells of the cell line NIH:OVCAR-3. Four weeks later animals were treated with 25, 50, 100, or 200 kBq 211At-MX35 F(ab')2 (n = 74). Another group of animals was treated with a nonspecific mAb: 100 kBq 211At-Rituximab F(ab')2 (n = 18). Eight weeks after treatment the animals were sacrificed and presence of macro- and microscopic tumors and ascites was determined. An MCP model was developed and compared with the experimentally determined tumor-free fraction (TFF). RESULTS: When treatment was given 4 weeks after cell inoculation, the TFFs were 25%, 22%, 50%, and 61% after treatment with 25, 50, 100, or 200 kBq (211)At-MX35 F(ab')2, respectively, the specific energy to irradiated cell nuclei varying between approximately 2 and approximately 400 Gy. CONCLUSION: As a significant increase in the therapeutic efficacy was observed between the activity levels of 50 and 100 kBq (TFF increase from 22% to 50%), the conclusion was that the MRA is approximately 100 kBq (211)At-MX35 F(ab')2. MCP was most consistent with the TFF when assuming a diffusion depth of 30 mum of the mAbs in the tumors.
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| 19. |
- Frisk, Christopher, 1985-, et al.
(författare)
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On the extraction of doping concentration from capacitance-voltage : A Cu2ZnSnS4 and ZnS sandwich structure
- 2017
-
Ingår i: IEEE Journal of Photovoltaics. - 2156-3381 .- 2156-3403. ; 7:5, s. 1421-1425
-
Tidskriftsartikel (refereegranskat)abstract
- The capacitance-voltage (C-V) method is frequently used to evaluate the net doping of thin-film solar cells, an important parameter for the function of solar cells. However, complex materials such as kesterites are challenging to characterize. To minimize ambiguity when determining the apparent doping concentration (N-A) of Cu2ZnSnS4 (CZTS), we fabricated and investigated different structures: CZTS/ZnS metal-insulator-semiconductor (MIS) device, stand-alone CZTS and ZnS metal-sandwich structures, and CZTS solar cells. Characterization was carried out by means of admittance spectroscopy (AS) and C-V measurements. ZnS exhibits excellent intrinsic properties, and with the high-quality MIS sample we managed to successfully isolate the capacitive response of the CZTS itself. N-A, as extracted from the MIS structure, is found to be more reliable and four times higher compared with the solar cell, impacting any estimated collection efficiency substantially. Data herein presented also show that CZTS has a substantial low-frequency dispersive capacitance and the extraction of N-A depends on the chosen measurement frequency, symptoms of presence of deep defects. Furthermore, the CZTS/ZnS MIS structure is strongly resilient to leakage currents at both forward and reverse voltage bias where contribution from deep defects is minimized and maximized, respectively.
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| 20. |
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| 21. |
- Heinle, Ulrich, et al.
(författare)
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High Voltage Devices on SOI
- 2001
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Ingår i: Presented at the Franco-Swedish Workshop on SOI, March 8-9, Grenoble, France.
-
Konferensbidrag (refereegranskat)
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| 22. |
- Hinnemo, Malkolm, 1986-, et al.
(författare)
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Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors
- 2018
-
Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 18:16, s. 6497-6503
-
Tidskriftsartikel (refereegranskat)abstract
- Sensing biomolecules in electrolytes of high ionic strength has been a difficult challenge for field-effect transistor-based sensors. Here, we present a graphene-based transistor sensor that is capable of detection of antibodies against protein p53 in electrolytes of physiological ionic strength without dilution. As these molecules are much larger than the Debye screening length at physiological ionic strengths, this paper proves the concept of detection beyond the Debye length. The measured signal associated with the expected specific binding of the antibodies to p53 is concluded to result from resistance changes at the graphene-electrolyte interface, since a sensor responding to resistance changes rather than charge variations is not limited by Debye screening. The conclusion with changes in interface resistance as the underlying phenomena that lead to the observed signal is validated by impedance spectroscopy, which indeed shows an increase of the total impedance in proportion to the amounts of bound antibodies. This finding opens up a new route for electrical detection of large-size and even neutral biomolecules for biomedical detection applications with miniaturized sensors.
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| 23. |
- Hoang Duc, Long, et al.
(författare)
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Feedback compensated 10 kW solid-state pulsed power amplifier at 352 MHz for particle accelerators
- 2019
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 90:10
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the first results of an in-house developed low-level radio frequency (LLRF) system and a 10 kW solid state power amplifier (SSPA). The design approach for the SSPA is based on eight resonant single-ended kilowatt modules combined using a planar Gysel combiner. Each of the single-ended modules is based on a two-stepped impedance resonant matching, allowing for harmonic suppression, simple design for massive production, and high-performance design. A design methodology to tune SSPA modules for optimum combining efficiency is presented thoroughly in the time domain. We characterize the power droop due to capacitor banks in the time domain. In open loop of compensation, it is about 1 kW within the pulse of peak value 10 kW and a duration of 3.5 ms. This may lead to the beam instability of the accelerator as particles are not provided with the same energy during the pulse. By incorporating our LLRF system, it is demonstrated that the objective of amplitude and phase stability is satisfied, as required in the European Spallation Source proton accelerator. The presented design also offers the advantages of compact form factor, low complexity, and better performance. In closed loop compensation, the variation of amplitude (pulse droop) is measured on the order of 20 W, which is equivalent to 0.2% at 10 kW peak output power.
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| 24. |
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| 25. |
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| 26. |
- Hoang Duc, Long, et al.
(författare)
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Time Domain Characterization of High Power Solid State Amplifiers for the Next Generation Linear Accelerators
- 2018
-
Ingår i: Microwave and optical technology letters (Print). - : Wiley. - 0895-2477 .- 1098-2760. ; 60:1, s. 163-171
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the time domain characterization of high power pulsed solid state amplifiers to be used forlinear accelerator applications. The study comprises nonlinear circuit envelope simulations and time domainenvelope measurements. Measurements and simulations are performed under the pulsed conditions (3.5 mspulse width, 5% duty cycle) specific to the European Spallation Source (ESS) high intensity proton accelerator.We measure the characteristics of pulsed LDMOS based power amplifiers such as: pulse droop along the pulse,efficiency, average envelope pulse amplitude and phase, pulse drain current waveform, pulse drain voltagewaveform, etc. A comparison between the measured results and the simulated results is also presented. Inaddition to the pulse profile characterization, the pulse to pulse (P2P) stability of the presented solid state poweramplifier (SSPA) is investigated as variations of amplitude and phase. The P2P stability simulations areintroduced as a combination of the Monte-Carlo simulations and the nonlinear circuit envelope simulations. Thesimulated results are used for fitting the P2P measurements to give an early insight of causes of instabilities ofthe nonlinear LDMOS models.
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| 27. |
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| 28. |
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| 29. |
- Larsson, Fredrik, et al.
(författare)
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Amorphous tin-gallium oxide buffer layers in (Ag,Cu)(In,Ga)Se2 solar cells
- 2020
-
Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 215
-
Tidskriftsartikel (refereegranskat)abstract
- Amorphous tin-gallium oxide (a-SGO) grown with atomic layer deposition was evaluated as a buffer layer in (Ag,Cu)(In,Ga)Se2 thin-film solar cells in search for a new material that is compatible with a variety of absorber band gaps. Hard and soft X-ray photoelectron spectroscopy on absorber/a-SGO stacks combined with J–V characterization of solar cells that were fabricated, showed that the conduction band alignment at the absorber/a-SGO interface can be tuned by varying the cation composition and/or growth temperature. Here, the surface band gap was 1.1 eV for the absorber. However, optical band gap data for a-SGO indicate that a suitable conduction band alignment can most likely be achieved even for wider absorber band gaps relevant for tandem top cells. A best efficiency of 17.0% was achieved for (Ag,Cu)(In,Ga)Se2/a-SGO devices, compared to η = 18.6% for the best corresponding CdS reference. Lower fill factor and open-circuit voltage values were responsible for lower cell efficiencies. The reduced fill factor is explained by a larger series resistance, seemingly related to interface properties, which are yet to be optimized. Some layer constellations resulted in degradation in fill factor during light soaking as well. This may partly be explained by light-induced changes in the electrical properties of a-SGO, according to analysis of Al/SGO/n-Si metal-oxide-semiconductor capacitors that were fabricated and characterized with J–V and C–V. Moreover, the introduction of a 1 nm thick Ga2O3 interlayer between the absorber and a-SGO improved the open-circuit voltage, which further indicates that the absorber/a-SGO interface can be improved.
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| 30. |
- Li, Ling-Guang, et al.
(författare)
-
Oxide-Free Silicon to Silicon Carbide Heterobond
- 2008
-
Ingår i: ESC Transactions. - : The Electrochemical Society. - 1938-6737 .- 1938-5862. ; 16:8, s. 377-383
-
Tidskriftsartikel (refereegranskat)abstract
- Thin crystalline device layersof Si were bonded to Si-faced SiC wafers, with eithera chemical or a thermal oxide interface layer. The interfacethermal oxide was successfully removed by oxygen out-diffusion for 2.5h in an Ar atmosphere at 1250 oC. XTEM micrographsshowed that an abrupt transition between Si and SiC withcomplete removal of the interlayer oxide had been obtained. Stressgenerated during the cool-down process after oxygen out-diffusion was shownto be compressive. IR imaging and an optical microscopy verifiedthat no cracks occurred during cool-down.
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| 31. |
- Li, Ling-Guang, 1982-, et al.
(författare)
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Thermal characterization of polycrystalline SiC
- 2014
-
Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 43:4, s. 1150-1153
-
Tidskriftsartikel (refereegranskat)abstract
- A study is made using fabricated thermal resistors in combination with two-dimensional (2D) electrothermal simulations to determine the thermal conductivity of polycrystalline SiC, single-crystalline SiC, and Si. The results show that the poly-SiC substrate has thermal conductivity of κ poly-SiC = 2.7 W K−1 cm−1, which is significantly lower than that of single-crystalline SiC.
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| 32. |
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| 33. |
- Martin, David, et al.
(författare)
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Buried aluminum nitride insulator for improving thermal conduction in SOI
- 2008
-
Ingår i: Proceedings of IEEE SOI Conference. ; , s. 105-106
-
Konferensbidrag (refereegranskat)abstract
- A new Si-on-AlN substrate has been fabricated and characterised both electrically and thermally. Thermal properties of the new substrate have been identified with a thermal resistance reduced by half to 47.5 K/W compared to reference SOI. Further improvements in fabrication of these new SOI substrates with regard to the alpha-Si layer, oxide layer and in AlN film quality itself would utillise the thermal conductivity of AlN even more.
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| 34. |
- Martin, David, et al.
(författare)
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Optimisation of a smooth multilayer Nickel Silicide surface for ALN growth
- 2008
-
Ingår i: Journal of Physics, Conference Series. - : IOP Publishing Ltd. - 1742-6588 .- 1742-6596. ; 100:4, s. 042014-
-
Tidskriftsartikel (refereegranskat)abstract
- For use in thin film electroacoustic (TEA) technology a few hundred nanometrethick nickel silicide (NiSi) electrode would need to be fabricated. A complete fabrication process for the formation of over 200 nm thick silicide films has been optimised for use as an electroacoustic electrode. Optimisation of silicidation temperature and identification of the mono phase of silicide is demonstrated. Thick electrodes are formed by depositing multilayers of silicon and nickel pairs onto silicon (Si) substrates before rapid thermal annealing. The numbers of multilayers and relative material thicknesses are optimized for both surface roughness and electrical resistivity. The growth of textured aluminium nitride (AlN) has been investigated on the optimised surfaces.
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| 35. |
- Martin, David, et al.
(författare)
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Thick NiSi Electrodes for AlN Electroacoustic Applications
- 2009
-
Ingår i: Electrochemical and solid-state letters. - : The Electrochemical Society. - 1099-0062 .- 1944-8775. ; 12:5, s. H182-H184
-
Tidskriftsartikel (refereegranskat)abstract
- Theuse of thick NiSi electrodes in electroacoustic resonators allows front-endintegration with integrated circuit technology. Problems are identified in theformation of thick nickel silicide (NiSi) electrodes via a singledeposition of Ni onto blank Si wafers. An alternative fabricationprocess based on the deposition and silicidation of a multilayerfilm is presented. The films were found to have lowresistivity and smooth surfaces, with the layered structure preserved evenafter silicidation. Textured piezoelectric films of (002) wurtzite AlN demonstrateda diffraction-peak width that narrows to 3.5° when deposited ona thick 10 pair NiSi film.
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| 36. |
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| 37. |
- Olsson, Jörgen, 1966-, et al.
(författare)
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A New Latch-Free LIGBT on SOI
- 2015
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Ingår i: Proceedings EUROSOI-ULIS. - 9781479969111 ; , s. 33-36
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Konferensbidrag (refereegranskat)abstract
- A new latch-free LIGBT on SOI is presented. The new device combines advantages from both LDMOS as well as LIGBT technologies; high breakdown voltage, high drive current density, low control voltages, at the same time eliminating latchup problems. Breakdown voltage of over 200 V, on-state current density over 3 A/mm and latch-free operation is demonstrated.
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| 38. |
- Olsson, Jörgen, 1966-, et al.
(författare)
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A New Latch-Free LIGBT on SOI with Very High Current Density and Low Drive Voltage
- 2016
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 115, s. 179-184
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Tidskriftsartikel (refereegranskat)abstract
- A new latch-free LIGBT on SOI is presented. The new device combines advantages from both LDMOS as well as LIGBT technologies; high breakdown voltage, high drive current density, low control voltages, at the same time eliminating latch-up problems. The new LIGBT has the unique property of independent scaling of the input control device, i.e. LDMOS, and the output part of the device, i.e. the p-n-p part. This allows for additional freedom in designing and optimizing the device properties. Breakdown voltage of over 200 V, on-state current density over 3 A/mm, specific on-resistance below 190 mWmm2, and latch-free operation is demonstrated.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
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| 44. |
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| 45. |
- Pearson, Patrick
(författare)
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Electrical Characterisation of (Ag,Cu)(In,Ga)Se2 Thin Film Solar Cells To Investigate Stability
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This licentiate thesis gives a summary of electrical characterisation techniques, detailing their use to investigate and understand stability and meta-stability in thin-film solar cells, with a focus on the chalcopyrite material system. Experimental data is used to illustrate the information that can be extracted with these measurements, highlighting the deeper insights that can be drawn from complementary measurements. For example, short-circuit current losses in (Ag,Cu)(In,Ga)Se2 after prolonged storage and annealing are attributed to changes in the net doping, as are significant open-circuit voltage losses observed after lightsoaking. Characterisation is also shown to suggest that the amount of Ag in the alloy plays a significant role in its stability, with a similar significance indicated for Ga.
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| 46. |
- Qiu, Zhijun, et al.
(författare)
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Role of Si implantation in control of underlap length in Schottky-barrier source/drain MOSFETs on ultrathin body SOI
- 2008
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Ingår i: Proceedings of ULIS. - NEW YORK : IEEE. ; , s. 175-178, s. 175-178
-
Konferensbidrag (refereegranskat)abstract
- This works demonstrates a novel approach using Si implantation prior to Pt deposition and PtSi formation to control the underlap length between the PtSi source/drain regions to the gate in Schottky-Barrier (SB-) MOSFETs. Dopant segregation at the PtSi/Si interface is used to enhance device performance. With the lon /Ioff current ratio as an indicator, optimized Si implant doses are found for both n- and p-channel SB-MOSFETs. Through an effective barrier width, the underlap length has direct implication on the leakage current.
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| 47. |
- Szaniawski, Piotr, et al.
(författare)
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A Systematic Study of Light-On-Bias Behavior in Cu(In,Ga)Se2 Solar Cells With Varying Absorber Compositions
- 2017
-
Ingår i: IEEE Journal of Photovoltaics. - 2156-3381 .- 2156-3403. ; 7:3, s. 882-891
-
Tidskriftsartikel (refereegranskat)abstract
- Light-on-bias effects were investigated in multiple Cu(In, Ga)Se2 solar cells with varying absorber layer compositions. A strong link between deformations caused by red-on-bias treatments in current-voltage (IV ) and capacitance-voltage (CV) characteristics was demonstrated. Similarly to red-on-bias, blue-on-bias leads to a local increase in static negative charge, but in samples with CdS buffers this increase is shifted away from the interface and has no impact on device performance. IV characteristics of samples with Cd-free buffers are not affected by any light-on-bias treatments, suggesting that CdS plays a vital role in the decreased performance after red-on-bias. A statistical approach was used to search for compositional trends in red-on-bias behavior. Deformation factors were defined for IV and CV characteristics before and after the treatment. While there is a strong relationship between the deformations observed in both types of measurements, the degree to which red-on-bias affects IV and CV curves can vary dramatically. These variations cannot be attributed to changes in composition, since no clear compositional trends were found. Rather, other factors related to sample manufacturing and to the buffer layer seem to have major impact on red-on-bias behavior.
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| 48. |
- Szaniawski, Piotr, et al.
(författare)
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Advancing the understanding of reverse breakdown in Cu(In,Ga)Se2 solar cells
- 2017
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Ingår i: IEEE Journal of Photovoltaics. - 2156-3381 .- 2156-3403. ; 7:4, s. 1136-1142
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Tidskriftsartikel (refereegranskat)abstract
- Reverse breakdown is investigated in multiple Cu(In,Ga)Se-2 solar cells with varying buffer layer thicknesses. A method to extract transition voltage, which marks the change of conduction mechanism that leads to electrical breakdown, is described as an alternative to the often less-meaningful breakdown voltage. Transition voltages for samples with CdS and ZnxSn1-xOy buffers are extracted from breakdown measurements performed in darkness and under illumination. The electric field is calculated for ZTO-based samples measured in darkness, and its implications for the energy band structure are examined. Fowler-Nordheim tunneling and Poole-Frenkel conduction are considered as candidates for the main breakdown mechanism in darkness. A model combining the two conduction mechanisms is proposed, and fits for experimental data are presented and discussed. Involvement of defects is debated, and defect-andbreakdown- related phenomena are showcased.
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| 49. |
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| 50. |
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