| 1. |
- 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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| 2. |
- 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. ; 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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| 3. |
- 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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| 4. |
- 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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| 5. |
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| 6. |
- Wen, Chenyu, et al.
(författare)
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Assessing kinetics of surface adsorption-desorption of gas molecules via electrical measurements
- 2016
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 223, s. 791-798
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Tidskriftsartikel (refereegranskat)abstract
- Gas sensing represents a grand research and application field. Owing to their unique structure of single-atom/molecule thickness, the emerging two-dimensional (2D) semiconductors are anticipated to display ultrahigh sensitivity capable of detecting minute changes in surface charge. To support the vast variety of gas sensing applications for domestic gases and environmental control, rapid and reliable quantitative analysis of measurement results based on established sensing mechanism and kinetics is essential. The present work uses graphene-based 2D sensors as a model system to establish the analytical capability for assessing the adsorption-desorption kinetics of gas molecules via electrical characterization. By linking the electrical current in graphene to the surface coverage of gas molecules and by incorporating the non-steady-state initial conditions for adsorption and desorption, an analytical model is established. Important kinetic parameters including activation energy, equilibrium coverage and adsorption-desorption time constants are obtained. The model can also facilitate real-world applications in gas sensing.
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| 7. |
- Xu, Peng, et al.
(författare)
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Investigation of resistivity dependent microwave annealing on Si substrates
- 2015
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Konferensbidrag (refereegranskat)abstract
- Heating of silicon substrates featuring different resistivity values by microwave annealing is investigated. The absorption of microwave energy for silicon wafers is found to be consistent with ohmic conduction loss theory. The strongest absorption occurs when the resistivity was around 10 Ω·cm. As the carrier concentration and the conductivity of silicon increase with temperature, the absorption of microwave energy also varies during the annealing processes. Furthermore, it is found that the electric field density around the annealed silicon wafer is stronger for higher conductive silicon substrates at fixed microwave power.
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| 8. |
- Yang, Hui, et al.
(författare)
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Improving Electrical Performance of Few-Layer MoS2 FETs via Microwave Annealing
- 2019
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 40:7, s. 1116-1119
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Tidskriftsartikel (refereegranskat)abstract
- A few-layer molybdenum disulfide (MoS2) has attracted great attention because of its novel electrical and optoelectrical properties for devices. In this letter, we perform a systematic study on the evolution of the electrical performance of the few-layer MoS2 field-effect transistors (FETs) under microwave annealing. As a result, obvious improvements on electrical properties are achieved for the sample annealed in N-2 ambience between 420 and 840 W. The on/off current ratio of similar to 8.34 x 10(8) and the hysteresis of 2.1 V, which are similar to 150 times higher and similar to 2.1 times smaller compared with that of fabricated MoS2 FET, respectively. The proposed technique provides a new method to approach high-performance few-layer MoS2 FETs with minimized parasitic resistances.
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| 9. |
- Ye, Qiangqiang, et al.
(författare)
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Ultra-Sensitive and Responsive Capacitive Humidity Sensor Based on Graphene Oxide
- 2015
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Ingår i: Proceedings of 2015 ieee 11th international conference on ASIC (ASICON). - : IEEE. - 9781479984855
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Konferensbidrag (refereegranskat)abstract
- Humidity sensors have attracted extensive attentions due to their various applications in environment monitoring, health care and internet of things. Graphene oxide has recently been exploited as a humidity sensing material because of its good hydrophilicity and excellent sensitivity. Here we report an ultra-sensitive and responsive capacitive humidity sensor using graphene oxide as sensing material. A capacitance change of ten times is observed when the relative humidity changes from 50% to 90%. The response and recovery time of the sensor are measured to be 0.066 and 0.154 s, respectively, which are several orders of magnitude shorter than conventional humidity sensors. Furthermore, its responses to flow rate, temperature and other vapors are also characterized.
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| 10. |
- Yue, Lei, et al.
(författare)
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Microwave annealing as a low thermal budget technique for ZnO thin-film transistors fabricated using atomic layer deposition
- 2017
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 38, s. 1390-1393
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Tidskriftsartikel (refereegranskat)abstract
- Microwave annealing (MWA) and furnace annealing are compared for their low thermal budget capability to improve the characteristics of ZnO-based thin-film transistors (TFTs). Both the ZnO channel and the Al2O3 gate dielectric are fabricated using atomic layer deposition. Using Si-wafer-susceptor assisted MWA with a substantial reduction of both annealing temperature and duration, significant improvements of the characteristics of the ZnO TFTs can be attained. A multi-step MWA process is found to further improve the characteristics of the TFTs. For the same microwave power and total duration, the field-effect mobility of the multi-step MWA TFT is 42% greater than that of the one-step MWA TFT with a similar sub-threshold swing. The multi-step MWA process can serve the purpose at temperatures as low as 220 degrees C.
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