正对电极结构型碳化硅光导开关的制备与性能研究

采用钒掺杂半绝缘6H-SiC衬底,以Ni/Au为接触电极制备了一系列正对电极结构型光导开关,对SiC光导开关进行了不同外加电压、激发光强、激发光波长条件下的测试,着重研究了SiC光导开关的光电吸收效应和光电响应性能.实验结果表明,532 nm的激光激发的脉冲信号宽度远小于1064 nm的激光激发的脉冲信号宽度,半绝缘6H-SiC衬底对532 nm激光的吸收系数在0.601～0.692 mm–1之间;采用532 nm的激光激发光导开关,获得了纳秒量级的响应信号;流经开关的瞬态电流随着外加电压和激发光能量的增加而增大,随着衬底厚度的增加而减小.

Preparation and Properties of Lateral Contact Structure SiC Photoconductive Semiconductor Switches

A series of lateral structural photoconductive semiconductor switches(PCSS) were fabricated on V-doped semi-insulating 6H-SiC substrate with the Ni/Au contacts.These PCSS were measured with different bias voltages, excitation energies and excitation wavelengths.The photoelectric absorption effect and photoelectric response of SiC PCSS were investigated.It is found that the absorption coefficient is between 0.601 and 0.692 mm–1 for semi-insulating 6H-SiC substrate when it is excited by 532 nm laser,and the corresponding pulse signal is much smaller than that excited by 1064 nm laser.Nanosecond-pulse signal is obtained for 6H-SiC PCSS excited by 532 nm laser.The peak current flowing through the switch is increased with increasing the bias voltage and excitation energy, while it is decreased with the increase in substrate thickness.