钒补偿度对SiC光导开关特性影响的研究

利用半导体器件仿真软件研究了钒掺杂半绝缘碳化硅(SiC)光导开关(PCSS)在电容放电电路中的瞬态特性。在非故意掺杂氮浓度为1×1014 cm-3、硼浓度为1×1011 cm-3和电容初始电压为1000 V的条件下,当钒浓度为1×1012 cm-3时,电路在初始阶段有一个完整的振荡脉冲电流,随后存在较大的泄露电流,当光导开关受到波长为532 nm、功率为2400 W/cm2激光的激发时,电容放电形成幅值约为88 A的陡峭脉冲电流,激光结束后电路还有较大的拖尾电流。随着钒浓度增加到1×1014 cm-3,初始阶段的振荡电流消失,漏电流和拖尾电流均减小,受到激光激发时所形成的脉冲电流幅值约为8 A,而钒浓度增加到1×1017 cm-3时,幅值减小到2.5 A。

Simulation of Vanadium Doped Concentration on the Effect of Characteristics of SiC Photoconducting Switches

SiC photoconducting switches (PCSS) have lots of advantages over conventional switches. By means of device simulator, a two dimension (2D) model of SiC PCSS was set up, and the effect of Vanadium doped concentration on the characteristics of SiC PCSS was explored in a capacitor discharging circuit. In the model, the concentrations of unintentional impurities nitrogen and boron were set to 1×1014 and 1×1011 cm-3 respectively, the wavelength and power of laser were set to 532 nm and 2400 W/cm2, and the initial voltage of the circuit was 1 000 V. When the vanadium doped concentration was 1×1012 cm-3, the circuit generated an unbroken current wave in the initial stage followed by a high leakage current. As soon as the switch was triggered by laser, a peak current of 88 A was formed. After laser triggering, a higher tail current was observed in the circuit. As the vanadium doped concentration was increased to 1×1014 cm-3, the leakage current and tail current both decreased, and the peak current was 8 A. Furthermore, when the vanadium doped concentration was 1×1017cm-3, the peak current reduced to 2.5 A.