High-Performance Lateral Avalanche Photodiode Based on Silicon-on-Insulator Structure

In this work, a silicon-on-insulator (SOI)-based lateral avalanche photodiode (APD) is proposed and fabricated. The device features lateral separate-absorption-multiplication (SAM) and electron-only injection. The bandwidth is optimized with the effective blocking of the deep photogenerated carriers by SOI structure. The device stability is also improved by additional shallow P-well region near the N+-region which can eliminate the edge breakdown induced by the curvature effect. Simulation results demonstrate that avalanche region (high electric field zone) is confined at the lateral PN+ junction. Experimental fabrication and characterizations are further realized, and this SOI-based lateral APD device exhibits high responsivity (1.92 A/W at 7.8 V for 300 nm), low dark current (below 5 V), large bandwidth (12.4 GHz at 8.2 V), and low breakdown voltage (similar to 7.8 V). The demonstrated device performance as well as the simple structure and good process compatibility can be attractive in future photo-detecting and advanced sensing applications.