We have developed an apparatus for producing high-density hydrogen plasma. The atomic hydrogen density was 3.0 × 1021 m?3 at a pressure of 30 Pa, a microwave power of 1000 W, and a hydrogen gas flow rate of 5 scc...We have developed an apparatus for producing high-density hydrogen plasma. The atomic hydrogen density was 3.0 × 1021 m?3 at a pressure of 30 Pa, a microwave power of 1000 W, and a hydrogen gas flow rate of 5 sccm. We confirmed that the temperatures of tungsten films increased to above 1000?C within 5 s when they were exposed to hydrogen plasma formed using the apparatus. We applied this phenomenon to the selective heat treatment of tungsten films deposited on amorphous silicon films on glass substrates and formed polycrystalline silicon films. To utilize this method, we can perform the crystalline process only on device regions. TFTs were fabricated on the polycrystalline silicon films and the electron mobilities of 60 cm2/Vs were obtained.展开更多
The negative gate bias stress(NBS)reliability of n-type polycrystalline silicon(poly-Si)thin-film transistors(TFTs)with a distinct defective grain boundary(GB)in the channel is investigated.Results show that conventio...The negative gate bias stress(NBS)reliability of n-type polycrystalline silicon(poly-Si)thin-film transistors(TFTs)with a distinct defective grain boundary(GB)in the channel is investigated.Results show that conventional NBS degradation with negative shift of the transfer curves is absent.The on-state current is decreased,but the subthreshold characteristics are not affected.The gate bias dependence of the drain leakage current at V_(ds)of 5.0 V is suppressed,whereas the drain leakage current at V_(ds)of 0.1 V exhibits obvious gate bias dependence.As confirmed via TCAD simulation,the corresponding mechanisms are proposed to be trap state generation in the GB region,positive-charge local formation in the gate oxide near the source and drain,and trap state introduction in the gate oxide.展开更多
A novel approach of two-step laser crystallization for the growth of poly-Si thin film on glass substrate is investigated. Using this approach, we fabricated poly-Si thin film transistors with electron mobility of 103...A novel approach of two-step laser crystallization for the growth of poly-Si thin film on glass substrate is investigated. Using this approach, we fabricated poly-Si thin film transistors with electron mobility of 103 cm2/V·s and on/off current ratio of 1×10~7.They are better than those of the poly-Si TFTs fabricated by conventional single-step excimer laser crystallization. We also analyzed the structure of the laser crystallized poly-Si thin film by spectroscopic ellipsometry, and proposed the models to simulate the poly-Si thin film and calculated the ellipsometric spectra. The calculated results are in good agreement with the measured results.展开更多
Based on Al induced crystallization (AIC) method, influences of different material structures on formation and characteristics of ploy-silicon thin films were studied and optimized. Al-Si films on glass with different...Based on Al induced crystallization (AIC) method, influences of different material structures on formation and characteristics of ploy-silicon thin films were studied and optimized. Al-Si films on glass with different structures (Si/Al/Glass, Al/Si/Glass, Si/Al/.../Si/Al/Glass) were deposited on glass substrates by sputtering method. All samples were annealed for MIC with varied time processes under 500°C N<SUB>2</SUB> environment. X-ray diffraction test and scanning electron microscope were adopted to characterize crystallization performance and surface topography of AIC poly-silicon samples after removing residual aluminum. The electrical properties were also characterized by Hall test method. Quick process and high performance of AIC ploy-silicon thin film can be both obtained by use of periodic structure samples.展开更多
Polycrystalline silicon thin films were prepared by RTCVD (rapid thermal chemica l vapor deposition) method on several substrates such as SSP (silicon sheet from powder) ribbon, poly-Si wafer and mono-Si wafer. Intra-...Polycrystalline silicon thin films were prepared by RTCVD (rapid thermal chemica l vapor deposition) method on several substrates such as SSP (silicon sheet from powder) ribbon, poly-Si wafer and mono-Si wafer. Intra-granular defects such as stacking faults, twins and microstructure defects were investigated on thin fil ms by scan electron microscopy (SEM) technique.展开更多
文摘We have developed an apparatus for producing high-density hydrogen plasma. The atomic hydrogen density was 3.0 × 1021 m?3 at a pressure of 30 Pa, a microwave power of 1000 W, and a hydrogen gas flow rate of 5 sccm. We confirmed that the temperatures of tungsten films increased to above 1000?C within 5 s when they were exposed to hydrogen plasma formed using the apparatus. We applied this phenomenon to the selective heat treatment of tungsten films deposited on amorphous silicon films on glass substrates and formed polycrystalline silicon films. To utilize this method, we can perform the crystalline process only on device regions. TFTs were fabricated on the polycrystalline silicon films and the electron mobilities of 60 cm2/Vs were obtained.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61971299 and 61974101)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20201201)+1 种基金the Fund from Suzhou Science and Technology Bureau(Grant No.SYG201933)the Fund from the State Key Laboratory of ASIC and System,Fudan University(Grant No.2021KF005)
文摘The negative gate bias stress(NBS)reliability of n-type polycrystalline silicon(poly-Si)thin-film transistors(TFTs)with a distinct defective grain boundary(GB)in the channel is investigated.Results show that conventional NBS degradation with negative shift of the transfer curves is absent.The on-state current is decreased,but the subthreshold characteristics are not affected.The gate bias dependence of the drain leakage current at V_(ds)of 5.0 V is suppressed,whereas the drain leakage current at V_(ds)of 0.1 V exhibits obvious gate bias dependence.As confirmed via TCAD simulation,the corresponding mechanisms are proposed to be trap state generation in the GB region,positive-charge local formation in the gate oxide near the source and drain,and trap state introduction in the gate oxide.
文摘A novel approach of two-step laser crystallization for the growth of poly-Si thin film on glass substrate is investigated. Using this approach, we fabricated poly-Si thin film transistors with electron mobility of 103 cm2/V·s and on/off current ratio of 1×10~7.They are better than those of the poly-Si TFTs fabricated by conventional single-step excimer laser crystallization. We also analyzed the structure of the laser crystallized poly-Si thin film by spectroscopic ellipsometry, and proposed the models to simulate the poly-Si thin film and calculated the ellipsometric spectra. The calculated results are in good agreement with the measured results.
文摘Based on Al induced crystallization (AIC) method, influences of different material structures on formation and characteristics of ploy-silicon thin films were studied and optimized. Al-Si films on glass with different structures (Si/Al/Glass, Al/Si/Glass, Si/Al/.../Si/Al/Glass) were deposited on glass substrates by sputtering method. All samples were annealed for MIC with varied time processes under 500°C N<SUB>2</SUB> environment. X-ray diffraction test and scanning electron microscope were adopted to characterize crystallization performance and surface topography of AIC poly-silicon samples after removing residual aluminum. The electrical properties were also characterized by Hall test method. Quick process and high performance of AIC ploy-silicon thin film can be both obtained by use of periodic structure samples.
基金This work was supported by the Chinese Academy of Sciences within"The Hundred Talent Projecr"(99-019-122288)National High Technical Research and Development Programme of China(No.2001AA513060)+1 种基金the 10th Five-Year Plan of Guangdong Province(A1100501)the National Natural Science Fundation of China(No.50376067).
文摘Polycrystalline silicon thin films were prepared by RTCVD (rapid thermal chemica l vapor deposition) method on several substrates such as SSP (silicon sheet from powder) ribbon, poly-Si wafer and mono-Si wafer. Intra-granular defects such as stacking faults, twins and microstructure defects were investigated on thin fil ms by scan electron microscopy (SEM) technique.
