一种应用于可见光通信系统的高带宽CMOS APD

A High Bandwidth CMOS APD for Visible Light Communication Systems

摘要:

采用标准的0.18μm CMOS工艺,设计了一种新型的应用于可见光通信系统的雪崩光电二极管(APD)。相较于传统的CMOS APD,该器件在深n阱/p衬底的结构基础上增加一层p阱,再在其上分别离子注入一层n⁺/p⁺层作为器件的雪崩击穿层,并且采用STI结构来防止器件边缘过早击穿。仿真结果表明,器件的雪崩击穿电压为9.9V,暗电流为1×10-12A,3dB带宽为5.9GHz,响应度为1.2A/W。由于STI保护环和短接深n阱/p衬底的结构设计,器件暗电流较传统结构CMOS APD降低了2个量级,且带宽提高了约10%。

Abstract:

A new kind of avalanche photodiode (APD) device applied in the visible light communication system was designed by using standard 0.18μm CMOS process. Compared to regular CMOS APD devices,the designed device adds a p-well layer to the deep n-well/p substrate structure, and an n⁺/p⁺ layer is deposited upon it. The n⁺/p⁺ layer acts as an avalanche breakdown layer of the device and an STI structure is used to prevent the edge breaks prematurely. The simulation results show that, the avalanche breakdown voltage is as low as 9.9V, the dark current is 1×10-12A, the 3dB bandwidth is 5.9GHz, and the responsibility is 1.2A/W. Due to the specific structure design of STI protection ring and short-circuit connection of deep n-well/p substrate, the dark current is reduced by about 2 orders of magnitude, and the bandwidth is improved by about 10% compared to that of regular CMOS APD.