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 (~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.