A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is ...A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is larger than 120. By use of device simulation,the cause of NDR is that increasing collector voltage makes the ultrathin base reach through and the device transforms from a bipolar state to a bulk barrier state. In addition, the simulated cutoff frequency is about 60-80GHz.展开更多
The generation of oxide charge for 4nm pMOSFETs under hot-carrier stress is investigated by the charge pumping measurements.Firstly,the direct experimental evidences of logarithmic time dependence of hole trapping is ...The generation of oxide charge for 4nm pMOSFETs under hot-carrier stress is investigated by the charge pumping measurements.Firstly,the direct experimental evidences of logarithmic time dependence of hole trapping is observed for pMOSFETs with different channel lengths under hot-carrier stress.Thus,the relationships of oxide charge generation,including electron trapping and hole trapping effects,with different stress voltages and channel lengths are analyzed.It is also found that there is a two-step process in the generation of oxide charge for pMOSFETs.For a short stress time,electron trapping is predominant,whereas for a long stress time,hole trapping dominates the generation of oxide charge.展开更多
Stress-induced leakage current (SILC) of ultrathin gate oxide is investigated by observing the generation of interface traps for n-MOSFET and p-MOSFET under hot-carrier stress.It is found experimentally that there is ...Stress-induced leakage current (SILC) of ultrathin gate oxide is investigated by observing the generation of interface traps for n-MOSFET and p-MOSFET under hot-carrier stress.It is found experimentally that there is linear correlation between the generation of interface traps and SILC for both types of MOSFET with different channel lengths (including 1,0.5,0.275,and 0.135μm) and different gate oxide thickness (4nm and 2.5nm).These experimental evidences show that the SILC has a strong dependence on interface traps.展开更多
Based on conventional double layer device, triple layer organic light-emitting diodes (OLEDs) with two heterostructures of indium-tin oxide (ITO)/N,N'-diphenyl-N,N'-bis(1-naphthyl)(1,1'-biphenyl)-4,4'-...Based on conventional double layer device, triple layer organic light-emitting diodes (OLEDs) with two heterostructures of indium-tin oxide (ITO)/N,N'-diphenyl-N,N'-bis(1-naphthyl)(1,1'-biphenyl)-4,4'-diamine(NPB)/2,9-dimethyl-4,7-diphenyl- 1,10-phenanthroline (BCP)/ 8-Hydroxyquinoline aluminum (Alq3)/Mg:Ag using vacuum deposition method have been fabricated. The influence of different film thickness of BCP layer on the performance of OLEDs has been investigated. The results showed that when the thickness of the BCP layer film gradually varied from 0.1 nm to 4.0 nm, the electrolumines- cence (EL) spectra of the OLEDs shifted from green to greenish-blue to blue, and the BCP layer acted as the recombination region of charge carriers related to EL spectrum, enhancing the brightness and power efficiency. The power efficiency of OLEDs reached as high as 7.3 lm/W.展开更多
YBCO superconducting films were prepared by Electron Beam Coevaporation method.All the YBCO films were annealed at 760°C in humidity range of 2.3-?9.5.Microstructure of the YBCO thin films was analyzed by means o...YBCO superconducting films were prepared by Electron Beam Coevaporation method.All the YBCO films were annealed at 760°C in humidity range of 2.3-?9.5.Microstructure of the YBCO thin films was analyzed by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM).Superconducting properties of the YBCO films were measured by electromagnetic induction method.XRD results showed that c-axis-oriented grains existed in the YBCO films.Morphologies of the YBCO films showed that all the films had a smooth and crack-free surface.YBCO films prepared at 7.3% humidity condition showed Jc value of 4.6 MA cm-2 at 77 K in self-field.展开更多
文摘A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is larger than 120. By use of device simulation,the cause of NDR is that increasing collector voltage makes the ultrathin base reach through and the device transforms from a bipolar state to a bulk barrier state. In addition, the simulated cutoff frequency is about 60-80GHz.
文摘The generation of oxide charge for 4nm pMOSFETs under hot-carrier stress is investigated by the charge pumping measurements.Firstly,the direct experimental evidences of logarithmic time dependence of hole trapping is observed for pMOSFETs with different channel lengths under hot-carrier stress.Thus,the relationships of oxide charge generation,including electron trapping and hole trapping effects,with different stress voltages and channel lengths are analyzed.It is also found that there is a two-step process in the generation of oxide charge for pMOSFETs.For a short stress time,electron trapping is predominant,whereas for a long stress time,hole trapping dominates the generation of oxide charge.
文摘Stress-induced leakage current (SILC) of ultrathin gate oxide is investigated by observing the generation of interface traps for n-MOSFET and p-MOSFET under hot-carrier stress.It is found experimentally that there is linear correlation between the generation of interface traps and SILC for both types of MOSFET with different channel lengths (including 1,0.5,0.275,and 0.135μm) and different gate oxide thickness (4nm and 2.5nm).These experimental evidences show that the SILC has a strong dependence on interface traps.
基金National Natural Science Foundation of China (Grant No.60425101)Program for New Cen-tury Excellent Talents in University (Grant No.NCET-06-0812)the Young Excellence Project of UESTC (Grant No.060206.)
文摘Based on conventional double layer device, triple layer organic light-emitting diodes (OLEDs) with two heterostructures of indium-tin oxide (ITO)/N,N'-diphenyl-N,N'-bis(1-naphthyl)(1,1'-biphenyl)-4,4'-diamine(NPB)/2,9-dimethyl-4,7-diphenyl- 1,10-phenanthroline (BCP)/ 8-Hydroxyquinoline aluminum (Alq3)/Mg:Ag using vacuum deposition method have been fabricated. The influence of different film thickness of BCP layer on the performance of OLEDs has been investigated. The results showed that when the thickness of the BCP layer film gradually varied from 0.1 nm to 4.0 nm, the electrolumines- cence (EL) spectra of the OLEDs shifted from green to greenish-blue to blue, and the BCP layer acted as the recombination region of charge carriers related to EL spectrum, enhancing the brightness and power efficiency. The power efficiency of OLEDs reached as high as 7.3 lm/W.
基金supported by the National Natural Science Foundation of China (Grant Nos.10921062 and 10502051)
文摘YBCO superconducting films were prepared by Electron Beam Coevaporation method.All the YBCO films were annealed at 760°C in humidity range of 2.3-?9.5.Microstructure of the YBCO thin films was analyzed by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM).Superconducting properties of the YBCO films were measured by electromagnetic induction method.XRD results showed that c-axis-oriented grains existed in the YBCO films.Morphologies of the YBCO films showed that all the films had a smooth and crack-free surface.YBCO films prepared at 7.3% humidity condition showed Jc value of 4.6 MA cm-2 at 77 K in self-field.
