中文摘要：

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（1MHz）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（100kHz）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。

英文摘要：

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.