不同钝化膜对InSb光伏探测器性能影响研究

Influence of Different Passivation Films on the Performance of InSb Photovoltaic Detector

采用3种不同钝化膜制备InSb探测器,测试不同周长/面积比二极管芯片的I-V特性曲线,通过对偏置电压为-0.1 V时的暗电流密度进行比较,分析了表面漏电流对InSb探测器性能的影响。实验结果表明SiO2+SiNx复合膜能大幅度降低器件表面暗电流,C-V测试结果也表明复合钝化膜能大幅度降低了界面固定电荷。将复合钝化膜应用到128×12815μm InSb焦平面探测器上,探测器芯片优值因子R0A≥5×10^4Ω·cm^2,较之前(R0A≈5×10^3Ω·cm^2)得到了极大改善。

Three different passivation films were used to prepare InSb detectors for testing the current –voltage(I-V) characteristic curves of chips with different perimeter–area ratios. The influence of surface leakage current on the performance of an InSb detector was analyzed by comparing the dark-current density at a bias voltage of-0.1 V. The test results indicated that SiO2+SiNx passivation could significantly reduce the surface dark current. The capacitance–voltage(C-V) test results also demonstrated that the composite passivation film could significantly reduce the interface fixed charge. A composite passivation-film process was applied for the preparation of a 128×128 15-μm InSb focal plane detector. The optimal value factor of the detector chip was R0 A ≥5×10^4Ω·cm^2, which was much higher than that before the test(R0 A≈5×103Ω·cm2).