InP衬底上的双载流子倍增雪崩光电二极管结构设计

Structural design of dual carrier multiplication avalanche photodiodes on InP substrate

雪崩光电二极管因其具有高的倍增被广泛应用于光通信、激光雷达等各种领域,为了适应极微弱信号探测应用场合,需要器件获得更高的增益值.当前雪崩光电二极管一般采用单载流子倍增方式工作,其倍增效果有限.本文设计了一种电子和空穴同时参与倍增的InP/In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As雪崩光电二极管结构,其中吸收层采用In_(0.53)Ga_(0.47)As材料,空穴倍增层采用InP材料,电子倍增层采用In_(0.52)Al_(0.48)As材料,两个倍增层分布在吸收层的上下两侧.采用Silvaco TCAD软件对此结构以及传统单倍增层结构进行了模拟仿真,对比单InP倍增层结构和单In_(0.52)Al_(0.48)As倍增层结构,双倍增层结构在95%击穿电压下的增益值分别约为前两者的2.3倍和2倍左右,由于两种载流子在两个倍增层同时参与了倍增,所以器件具有更大的增益值,且暗电流并没有增加,有望提高系统探测的灵敏度.

Avalanche photodiodes are widely used in various fields,such as optical communication and laser radar,because of their high multiplication.In order to adapt to very weak signal detection applications,devices are required to have higher gain values.The existing avalanche photodiodes generally use single carrier multiplication mode of operation,its multiplication effect is limited.In this paper is designed an InP/In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As avalanche photodiode structure with electrons and holes jointly involved in multiplication.In this structure,In0.53Ga0.47As material is used for the absorption layer,InP material is used for the hole multiplication layer,In0.52Al0.48As is used for the electron multiplication layer,and the two multiplication layers are distributed on the upper side and lower side of the absorber layer.Under the reverse bias,the photogenerated electrons and the absorber-layer generated holes can enter into the respective multiplier layers in different directions and create the avalanche multiplication effect,so that the carriers are fully utilized.This structure and the conventional single multiplication layer structure are simulated by Silvaco TCAD software.Comparing the single InP multiplication layer structure with the single In_(0.52)Al_(0.48)As multiplication layer structure,the gain value of the double multiplication layer structure at 95%breakdown voltage is about 2.3 times and about 2 times of the former two,respectively,and the device has a larger gain value because both carriers are involved in multiplication in both multiplication layers at the same time.The structure has a dark current of 1.5 nA at 95%breakdown voltage,which does not increase in comparison with the single multiplication layer structure,owing to the effective control of the electric field inside the structure by multiple charge layers.Therefore,this structure is expected to improve the detection sensitivity of the system.