采用电流-电压曲线研究近红外铟镓砷(InGaAs)光敏芯片的暗电流, 并分析了InGaAs光敏芯片暗电流与InGaAs焦平面组件暗信号的关系。结果表明, 温度下降到273 K时, 反向偏压-100 mV时, 扩散电流是光敏芯片暗电流的主要机制, 反向偏压-400 mV时, 产生-复合电流是光敏芯片暗电流的主要机制, 偏压较小时, 界面电流对光敏芯片暗电流贡献增加。光敏芯片各元的暗电流是产生焦平面暗信号的主要原因, 反向偏压3 mV时InGaAs光敏芯片的最小暗电流0.92 pA, 积分时间为50 ms情况下在读出电路输出端上产生了2.87×105电子数, 焦平面对应元的动态范围最大56 dB。同时读出电路CTIA反馈端元与元之间固有差异导致探测器上实际加载上不同的偏压, 也增加了暗信号输出的非均匀。实验表明进一步降低光敏芯片暗电流是提高InGaAs焦平面组件动态范围的重要途径之一。

The dark currents of near-infrared InGaAs detectors were studied by I-V curves, the relations between the dark currents of InGaAs detectors and the dark signals of InGaAs FPA were analyzed. The result shows that the dark current is dominated by diffusion current at -100 mV reverse bias down to about 273 K, the dark current is dominated by generation-recombination current at -400 mV reverse bias down to about 273 K, the effect of interface current on the dark current increase at the smaller bias voltage.The dark currents of InGaAs linear detectors is the major reason of the dark signal output of InGaAs FPA, the smallest dark current among InGaAs linear detectors is about 0.92 pA at -3 mV reverse bias, which cause the corresponding electrons of 2.87×105 in FPA and the corresponding dynamic range of 56 dB. Pixel-to-pixel variations of CTIA in ROIC result in variation of the actual bias voltages applied to the diodes which increase non-uniformity of the dark signal output of InGaAs FPA. The result shows that the further decrease of the dark current of InGaAs detectors is an improvet approach to improving the dynamic range of InGaAs FPA.