Indirect Avalanche Event Detection of Single Photon Avalanche Diode Implemented in CMOS FDSOI Technology

Abstract In this letter, a novel indirect avalanche event detection is proposed and demonstrated for Single Photon Avalanche Diodes (SPADs) implemented in CMOS 28 nm Fully Depleted Silicon-On-Insulator (FDSOI) technology. This approach is based on the capacitive coupling between the P-well, i.e. SPAD anode, and the transistor channel, separated by the ultra-thin buried oxide. The associated body-biasing effect is used to dynamically modulate the output of a simple voltage divider synchronously with the SPAD activity. A test-chip has been designed, fabricated and characterized to validate the proposed approach. This novel architecture opens the way for innovative SPAD processing circuitry implemented in 3D native CMOS FDSOI.