SAGCM雪崩式光偵測二極體增益分析與提前崩潰改善之模擬

Abstract

本論文透過量測SAGCM雪崩式光電二極體的光暗電流，分析其崩潰電壓與增益行為，研究不同的元件設計參數是否能改善因擴散邊緣強電場導致的提前崩潰，以及改善的能力，並透過這兩項參數將元件分為四類：發散型A、發散型B、過渡型、線性型，其中發散型的表現比對照組更差，實務設計上應避免，線性型則擁有較高崩潰電壓與線性分佈的增益，不僅可以削弱邊緣強電場在高偏壓時的主導性，還擁有更高的可預測性。基於某些設計的FGR確實可以提升元件崩潰電壓，我們利用TCAD模擬了更多結構來釐清提前崩潰被進一步改善的可能性，其中更提出了擁有第二AGR的雙重AGR結構，該結構利用一個擴散深度更淺的第二AGR來分散第一AGR邊緣的電場，特定的第二AGR深度可以使得崩潰電壓提升2.1V，並且崩潰時的中央區電場也更加提升。

This paper investigates the improvement of premature breakdown caused by strong electric fields near the diffusion edge and its associated gain behavior by measuring the photocurrent and darkcurrent of actual components. Different design of FGR’s parameters are analyzed to determine whether they can enhance the performance and mitigation of premature breakdown. Based on two key parameters, breakdown voltage and gain behavior, the components are classified into four categories: Divergent Type A, Divergent Type B, Transitional Type, and Linear Type. Divergent Types exhibit inferior performance compared to the control group and should be avoided in practical designs, while Linear Types show higher breakdown voltage and linear gain distribution, which not only mitigates the dominance of edge electric fields at high bias voltages but also provides improved predictability. Through certain FGR designs, it is indeed possible to increase the component's breakdown voltage. To explore the potential for further mitigation in premature breakdown, additional structures are simulated using TCAD (Technology Computer-Aided Design). Among them, a dual AGR structure with a secondary AGR is proposed. This structure employs a shallower second AGR to disperse the electric field near the first AGR edge. By adjusting the depth of the second AGR, the breakdown voltage can be increased by 2.1V, while also further enhancing the electric field in the central region during breakdown.