| 1. |
- Chen, Si, et al.
(författare)
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A graphene field-effect capacitor sensor in electrolyte
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:15, s. 154106-
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Tidskriftsartikel (refereegranskat)abstract
- The unique electronic properties of graphene are exploited for field-effect sensing in both capacitor and transistor modes when operating the sensor device in electrolyte. The device is fabricated using large-area graphene thin films prepared by means of layer-by-layer stacking. Although essentially the same device, its operation in the capacitor mode is found to yield more information than in the transistor mode. The capacitor sensor can simultaneously detect the variations of surface potential and electrical-double-layer capacitance at the graphene/electrolyte interface when altering the ion concentration. The capacitor-mode operation further facilitates studies of the molecular binding-adsorption kinetics by monitoring the capacitance transient
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| 2. |
- Fu, Chaochao, et al.
(författare)
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Crystallization of amorphous silicon on glass substrate by microwave annealing for thin-film-transistor applications
- 2015
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Konferensbidrag (refereegranskat)abstract
- There is a rising demand for low temperature polysilicon TFT these years due to the rapidly increasing market of high resolution display panels. In this paper, both low temperature microwave annealing and laser annealing were used to crystallize amorphous silicon film on glass substrate. It is found that both methods had successfully transferred the amorphous silicon into polysilicon according to Raman spectra results. The microwave crystallized polysilicon had smaller grain size and lower tensile stress than the laser crystallized one. After implantation and activation of BF2 and P, sheet resistance values of the BF2-implanted microwave crystallized samples were similar to that of laser crystallized ones. However, for the P implanted samples, the microwave crystallized samples had two to three magnitude higher sheet resistance compared with the laser crystallized ones.
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| 3. |
- Fu, Chaochao, et al.
(författare)
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Schottky Barrier Height Tuning via the Dopant Segregation Technique through Low-Temperature Microwave Annealing
- 2016
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Ingår i: Materials. - : MDPI AG. - 1996-1944 .- 1996-1944. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- The Schottky junction source/drain structure has great potential to replace the traditional p/n junction source/drain structure of the future ultra-scaled metal-oxide-semiconductor field effect transistors (MOSFETs), as it can form ultimately shallow junctions. However, the effective Schottky barrier height (SBH) of the Schottky junction needs to be tuned to be lower than 100 meV in order to obtain a high driving current. In this paper, microwave annealing is employed to modify the effective SBH of NiSi on Si via boron or arsenic dopant segregation. The barrier height decreased from 0.4–0.7 eV to 0.2–0.1 eV for both conduction polarities by annealing below 400 °C. Compared with the required temperature in traditional rapid thermal annealing, the temperature demanded in microwave annealing is ~60 °C lower, and the mechanisms of this observation are briefly discussed. Microwave annealing is hence of high interest to future semiconductor processing owing to its unique capability of forming the metal/semiconductor contact at a remarkably lower temperature.
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| 4. |
- Fu, Chaochao, et al.
(författare)
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Understanding the microwave annealing of silicon
- 2017
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Ingår i: AIP Advances. - : AMER INST PHYSICS. - 2158-3226. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- Though microwave annealing appears to be very appealing due to its unique features, lacking an in-depth understanding and accurate model hinder its application in semiconductor processing. In this paper, the physics-based model and accurate calculation for the microwave annealing of silicon are presented. Both thermal effects, including ohmic conduction loss and dielectric polarization loss, and non-thermal effects are thoroughly analyzed. We designed unique experiments to verify the mechanism and extract relevant parameters. We also explicitly illustrate the dynamic interaction processes of the microwave annealing of silicon. This work provides an in-depth understanding that can expedite the application of microwave annealing in semiconductor processing and open the door to implementing microwave annealing for future research and applications.
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| 5. |
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| 6. |
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| 7. |
- Hu, Cheng, et al.
(författare)
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Characterization of Ni(Si,Ge) films on epitaxial SiGe(100) formed by microwave annealing
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:9, s. 092101-
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Tidskriftsartikel (refereegranskat)abstract
- Microwave annealing (MWA) is investigated as an alternative technique to rapid thermal processing with halogen lamp heating (RTP) for low-temperature silicide formation on epitaxially grown Si0.81Ge0.19 layers. Phase formation, resistivity mapping, morphology analysis, and composition evaluation indicate that the formation of low-resistivity NiSi1-xGex by means of MWA occurs at temperatures about 100 degrees C lower than by RTP. Under similar annealing conditions, more severe strain relaxation and defect generation are therefore found in the remaining Si0.81Ge0.19 layers treated by MWA. Although silicidation by microwave heating is in essence also due to thermal effects, details in heating mechanisms differ from RTP.
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| 8. |
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| 9. |
- Li, Chen, et al.
(författare)
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Rapid Four-Point Sweeping Method to Investigate Hysteresis of MoS2 FET
- 2020
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Ingår i: IEEE Electron Device Letters. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0741-3106 .- 1558-0563. ; 41:9, s. 1356-1359
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Tidskriftsartikel (refereegranskat)abstract
- Hysteresis is a frequently observed phenomenon in the transfer characteristics of thin film transistors. Charge trapping/de-trapping processes of gate oxide and gate-channel interface are commonly known to be the origin of hysteresis and correlated to low frequency noise (LFN) properties of the devices. In this letter, a rapid four-point sweeping method (RFSM) is proposed to reveal the dependence of hysteresis, as well as the distribution of effective trap density on sweeping rate and gate bias range. Based on the RFSM, the hysteresis properties of four-layer MoS2 FETs are studied in detail. The experimental results demonstrate that the hysteresis and trap density at different frequencies and gate voltages, which could further roughly map the traps with different time constants and energy depths, can be obtained by the simple RFSM. Trap density estimated by RFSM shows a comparable range with that extracted from LFN, indicating that the traps inducing the hysteresis may also cause LFN.
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| 10. |
- Li, Hui, et al.
(författare)
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Accelerating Gas Adsorption on 3D Percolating Carbon Nanotubes
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- In the field of electronic gas sensing, low-dimensional semiconductors such as single-walled carbon nanotubes (SWCNTs) can offer high detection sensitivity owing to their unprecedentedly large surface-to-volume ratio. The sensitivity and responsivity can further improve by increasing their areal density. Here, an accelerated gas adsorption is demonstrated by exploiting volumetric effects via dispersion of SWCNTs into a percolating three-dimensional (3D) network in a semiconducting polymer. The resultant semiconducting composite film is evaluated as a sensing membrane in field effect transistor (FET) sensors. In order to attain reproducible characteristics of the FET sensors, a pulsed-gate-bias measurement technique is adopted to eliminate current hysteresis and drift of sensing baseline. The rate of gas adsorption follows the Langmuir-type isotherm as a function of gas concentration and scales with film thickness. This rate is up to 5 times higher in the composite than only with an SWCNT network in the transistor channel, which in turn results in a 7-fold shorter time constant of adsorption with the composite. The description of gas adsorption developed in the present work is generic for all semiconductors and the demonstrated composite with 3D percolating SWCNTs dispersed in functional polymer represents a promising new type of material for advanced gas sensors.
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