分析并比较了4H-SiC p-i-n紫外光电探测器的电容-电压(C-V)特性 随温度和偏置电压的变化情况,观测到4H-SiC p-i-n结构中的深能级缺陷。结果表明：由于近零偏压时探测器i型层已处于 耗尽状态,其高频(1 MHz) C-V特性几乎不随反向偏压变化。随着温度升高,被热离化的自由载流子数量增多导 致高频结电容随之增大；探测器的低频(100 kHz)结电容比高频结电容具有更强的电压和温度依赖性,原因在于被深能级缺陷俘获的载流 子随反向偏压增大或随温度升高而被离化,从而对结电容产生影响。

The capacitance-voltage (C-V) characteristics of 4H-SiC p-i-n ultraviolet(UV) photodetector with temperature and bias voltage are analyzed and compared. The deep-level defects in 4H-SiC p-i-n structure are observed. Results show that the high-frequency (1 MHz) C-V characteristics almost do not change with reverse bias due to the fact that i-layer of detector is in depletion state under near zero bias. The high-frequency junction capacitances increase as the result of the number increasing of thermally ionized free carriers with the increasing of temperature. Low-frequency (100 kHz) junction capacitances of the detector have a stronger voltage and temperature dependence than that of high-frequency junction capacitance, and the reason is that the carriers trapped by the deep-level defects are ionized with increasing of reverse bias or temperature, which affects the junction capacitance.