Modeling and Electrical Simulations of Thin-Film Gated SOI Lateral PIN Photodetectors for High Sensitivity and Speed Performances

Thin-film gated SOI lateral PIN (LPIN) photodetectors was proposed, with ITO deposited on topside as transparent gate electrode. This paper investigates performances of the photodetectors versus the P-doping level in the intrinsic region (I-region), with gate voltage applied. We present analytical model and two-dimensional Atlas simulations of the current characteristics, sensitivity and speed performance. At a 400 nm wavelength, the output photocurrent approximately reaches the available photocurrent, the internal quantum efficiencies yield over 90%, even nearly 100% with various dopings. In terms of speed performances, the total -3dB frequencies of the photodetectors are up to a few tens of MHz with the intrinsic length of 8 um. And dark currents as low as 10− 14 A can give a high ratio of more than 107 between illuminated to dark currents under low-voltage operation. With such advantageous electrical characteristics, thin-film gated SOI LPIN photodetectros appear highly suitable for optical storage systems and blue DVD applications.