4×44H-SiC紫外雪崩光电二极管阵列

4×4 4H-SiC Ultraviolet Avalanche Photodiode Arrays

碳化硅(SiC)雪崩光电二极管(APD)固态紫外(UV)探测器在很多领域具有重要的潜在应用价值。针对4H-SiC APD阵列目前面临的像元良率较低和击穿电压一致性差等问题,基于吸收电荷倍增分离结构,设计制备了一款4×4的4H-SiC APD阵列芯片,并对其紫外探测性能和阵列像元的一致性进行了测试与分析。结果显示,所制备的4×4 4H-SiC APD阵列不但具有较大的像元面积,而且具有较好的紫外探测性能、较高的像元良率和较好的击穿电压一致性。室温下,像元的雪崩增益高达10~5以上,单位增益最大外量子效率为70%,阵列中16个像元均实现雪崩硬击穿,像元良率达到100%,击穿电压保持高度一致,均为157.2 V,在95%击穿电压时像元的暗电流全部小于1 nA。4H-SiC APD阵列性能的提高将为4H-SiC APD在紫外成像领域的应用奠定基础。

Silicon carbide(SiC) avalanche photodiode(APD)-based solid-state ultraviolet(UV) detectors are of very importance in many potential applications. To solve the problems of low pixel yield and low uniformity of the breakdown voltage for 4 H-SiC APD arrays, a 4×4 4 H-SiC APD array chip was designed and fabricated based on the separate absorption charge multiplication epi-structure. In addition, the UV detection performance of the array chips and the uniformity of pixels in the array were tested and analyzed. The results show that the fabricated 4×4 4 H-SiC APD arrays with large-size pixels exhibit excellent UV detection performance, high pixel yield and high-uniformity breakdown voltage. At room temperature, high avalanche gain of over 10~5 is obtained for the pixels in the array. The unity-gain maximum external quantum efficiency(QE) is 70%. Moreover, all of the 16 pixels show hard avalanche breakdown, resulting in a pixel yield of 100%. A high-uniformity breakdown voltages are achieved at 157.2 V, and the dark currents of pixels at 95% breakdown voltage for all the pixels are below 1 nA. The improvements of 4 H-SiC APD array performances will lay the foundation for UV imaging applications of 4 H-SiC APDs.