We present the design consideration and fabrication of 4H-SiC trenched-and-implanted vertical junction field-effect transistors （TI-VJFETs）. Different design factors, including channel width, channel doping, and mes...We present the design consideration and fabrication of 4H-SiC trenched-and-implanted vertical junction field-effect transistors （TI-VJFETs）. Different design factors, including channel width, channel doping, and mesa height, are con- sidered and evaluated by numerical simulations. Based on the simulation result, normally-on and normally-off devices are fabricated. The fabricated device has a 12 μm thick drift layer with 8 × 10^15 cm^-3 N-type doping and 2.6 μm channel length. The normally-on device shows a 1.2 kV blocking capability with a minimum on-state resistance of 2.33 mΩ.cm2, while the normally-off device shows an on-state resistance of 3.85 mΩ.cm2. Both the on-state and the blocking performances of the device are close to the state-of-the-art values in this voltage range.展开更多
研究了寄生电感对基于常通型碳化硅(silicon carbide,SiC)结型场效应晶体管(junction field effect transistor,JFET)串联结构的中压直流固态断路器(solid state circuit breaker,SSCB)过电压的影响,并在此基础上提出了一种SSCB的过电...研究了寄生电感对基于常通型碳化硅(silicon carbide,SiC)结型场效应晶体管(junction field effect transistor,JFET)串联结构的中压直流固态断路器(solid state circuit breaker,SSCB)过电压的影响,并在此基础上提出了一种SSCB的过电压抑制方法。首先介绍了基于常通型SiC JFET器件串联结构的SSCB拓扑及工作原理,建立了考虑完整回路寄生电感的SiC JFET串联结构开关过程的数学模型。其次利用MATLAB软件对数学模型进行解析计算,揭示了SSCB开关过程中寄生电感对SiC JFET器件串联运行时过电压的影响机理,并利用PSPICE仿真结果验证了理论分析的正确性。最后设计了一种适用于SSCB过电压抑制的单栅极驱动及缓冲电路,并通过SSCB实验样机验证了所提方法的有效性。展开更多
This paper reports the experimental results for the humidity dependent properties of an organic field effect transistor.The organic field effect transistor was fabricated on thoroughly cleaned glass substrate,in which...This paper reports the experimental results for the humidity dependent properties of an organic field effect transistor.The organic field effect transistor was fabricated on thoroughly cleaned glass substrate,in which the junction between the metal gate and the organic channel plays the role of gate dielectric.Thin films of organic semiconductor copper phthalocynanine（CuPc） and semitransparent Al were deposited in sequence by vacuum thermal evaporation on the glass substrate with preliminarily deposited Ag source and drain electrodes.The output and transfer characteristics of the fabricated device were performed.The effect of humidity on the drain current,drain current-drain voltage relationship, and threshold voltage was investigated.It was observed that humidity has a strong effect on the characteristics of the organic field effect transistor.展开更多
在大深度测量时,由于传统空心线圈传感器自身空心线圈和差分放大器部分引入了噪声,致使感应式磁传感器探测灵敏度降低,无法满足地质探测深度的需要。针对此问题,通过理论分析空心线圈磁传感器中空心线圈的物理结构和前置放大电路的机理...在大深度测量时,由于传统空心线圈传感器自身空心线圈和差分放大器部分引入了噪声,致使感应式磁传感器探测灵敏度降低,无法满足地质探测深度的需要。针对此问题,通过理论分析空心线圈磁传感器中空心线圈的物理结构和前置放大电路的机理,研究引入噪声的主要来源,建立基于结型场效应晶体管(JFET)的感应式磁传感器等效模型,提出一种低噪声宽带宽空心线圈磁传感器。同时,分析该模型下差分放大器的频域特性,给出磁传感器输入噪声的仿真结果。在屏蔽室内和野外试验对所研制的磁传感器性能进行测试。研究结果表明:该磁传感器的3 d B响应带宽达到42.3 k Hz,相比于磁传感器3D-3响应带宽增加了1倍。在输入噪声水平方面,其输入噪声在频率为10 k Hz时为1.97 n V/Hz1/2,较磁传感器3D-3信噪比提高了10.04 d B,为感应式磁传感器在实际项目应用提供了可靠的性能保障。展开更多
基金supported by the National High Technology Research and Development Program of China(Grant No.2011AA050401)the National Science Fundfor Distinguished Young Scholars,China(Grant No.51225701)
文摘We present the design consideration and fabrication of 4H-SiC trenched-and-implanted vertical junction field-effect transistors （TI-VJFETs）. Different design factors, including channel width, channel doping, and mesa height, are con- sidered and evaluated by numerical simulations. Based on the simulation result, normally-on and normally-off devices are fabricated. The fabricated device has a 12 μm thick drift layer with 8 × 10^15 cm^-3 N-type doping and 2.6 μm channel length. The normally-on device shows a 1.2 kV blocking capability with a minimum on-state resistance of 2.33 mΩ.cm2, while the normally-off device shows an on-state resistance of 3.85 mΩ.cm2. Both the on-state and the blocking performances of the device are close to the state-of-the-art values in this voltage range.
文摘This paper reports the experimental results for the humidity dependent properties of an organic field effect transistor.The organic field effect transistor was fabricated on thoroughly cleaned glass substrate,in which the junction between the metal gate and the organic channel plays the role of gate dielectric.Thin films of organic semiconductor copper phthalocynanine（CuPc） and semitransparent Al were deposited in sequence by vacuum thermal evaporation on the glass substrate with preliminarily deposited Ag source and drain electrodes.The output and transfer characteristics of the fabricated device were performed.The effect of humidity on the drain current,drain current-drain voltage relationship, and threshold voltage was investigated.It was observed that humidity has a strong effect on the characteristics of the organic field effect transistor.
文摘在大深度测量时,由于传统空心线圈传感器自身空心线圈和差分放大器部分引入了噪声,致使感应式磁传感器探测灵敏度降低,无法满足地质探测深度的需要。针对此问题,通过理论分析空心线圈磁传感器中空心线圈的物理结构和前置放大电路的机理,研究引入噪声的主要来源,建立基于结型场效应晶体管(JFET)的感应式磁传感器等效模型,提出一种低噪声宽带宽空心线圈磁传感器。同时,分析该模型下差分放大器的频域特性,给出磁传感器输入噪声的仿真结果。在屏蔽室内和野外试验对所研制的磁传感器性能进行测试。研究结果表明:该磁传感器的3 d B响应带宽达到42.3 k Hz,相比于磁传感器3D-3响应带宽增加了1倍。在输入噪声水平方面,其输入噪声在频率为10 k Hz时为1.97 n V/Hz1/2,较磁传感器3D-3信噪比提高了10.04 d B,为感应式磁传感器在实际项目应用提供了可靠的性能保障。
