选用钒掺杂浓度为0.2at%的高质量6H-SiC晶体,电阻率为7.0×10^8Ω·cm,研制出超快大功率SiC光导开关.在脉冲宽度为20ns的光源激发下,分别测试了在不同的偏置电压和光能条件下开关的电脉冲输出特性.结果表明:1mm电极间隙的SiC开关器件的性能优越,耐偏压高,光导电脉冲的上升时间快(6.8ns),脉宽〈20ns,稳定性好.负载为40Ω的电阻上输出线性电脉冲电压随开关的偏置电压和光强增大而增大,在2.5kV的偏置电压下,最大瞬时电流约为57.5A,瞬时功率高达132kW.
High-power photoconductive semiconductor switches (PCSS) were fabricated on 0.2at% vanadium-doped semi-insulating 6H-SiC (7.0× 10^8Ω·cm). V-doped 6H-SiC PCSS with lmm gap displays a fast rise time (6.8ns), short photoconductivity pulse width (less than 20ns) and high-speed photovoltaic response to 20ns laser pulse. The experimental results show that the linear peak voltage is increased with increasing bias voltage and excitation energy. The typical maximum photocurrent of the device at 2.5kV is about 57.5A, the peak electrical power delivered to a 40Ω load is 132kW.