通过商用半导体模拟器MEDICI对700 V 4H-SiC晶闸管开通特性进行了模拟研究。模拟结果表明阳极电压小于100 V时,开通过程符合扩散模型,电压更高时,开通时间随阳极电压升高而迅速下降,符合场开通机制。不同于Si及GaAs晶闸管,SiC晶闸管p型耐压层中浅能级杂质Al使得其开通时间随温度的升高而降低。较厚的基区使得电导调制效应只发生在发射区与基区边界一个范围之内,随着温度的升高,其余部分的载流子数目指数增加,压降指数减小。开通时间随着门极触发电流的加大而逐渐缩短,减小到一定程度时,减小速度明显变缓。
An optically controlled SiC/SiCGe lateral power transistor based on superjunction structure has been proposed, in which n-SiCGe/p-SiC superjunction structure is employed to improve device figure of merit.Performance of the novel optically controlled power transistor was simulated using Silvaco Atlas tools,which has shown that the device has a very good response to the visible light and the near infrared light.The optoelectronic responsivities of the device at 0.5μm and 0.7μm are 330 mA/W and 76.2 mA/W at 2 V based voltage,respectively.
In this paper,a 4H-SiC semi-superjunction (SJ) Schottky barrier diode is analysed and simulated.The semi-SJ structure has an optimized design and a specific on-resistance lower than that of conventional SJ structures,which can be achieved without increasing the process difficulty.The simulation results show that the specific on-resistance and the softness factor depend on the aspect and thickness ratios,and that by using the semi-SJ structure,specific on-resistance can be reduced without decreasing the softness factor.It is observed that a trade-off exists between the specific on-resistance and the softness of the diode.
A novel optically controlled SiCGe/SiC heterojunction transistor with charge-compensation technique has been simulated by using commercial simulator.This paper discusses the electric field distribution,spectral response and transient response of the device.Due to utilizing p-SiCGe charge-compensation layer,the responsivity increases nearly two times and breakdown voltage increases 33%.The switching characteristic illustrates that the device is latch-free and its fall time is much longer than the rise time.With an increase of the light power density and wavelength,the rise time and fall time will become shorter and longer,respectively.In terms of carrier lifetime,a compromise should be made between the responsivity and switching speed,the ratio of them reaches maximum value when the minority carrier lifetime equals 90 ns.
