Suppressing crosstalk in the photoelectron in-situ sensing device (PISD) by double SOI

In our previous work on silicon-on-insulator (SOI) photodetectors, we have used the deep-depletion effect in SOI substrates to construct the photoelectron in-situ sensing device (PISD). The PISD is a one-transistor active pixel sensor (1T-Aps) that is more compact than conventional CMOS sensors. In this work, we study the crosstalk between different pixels in the PISD, which is severe in a conventional SOI substrate. Through TCAD simulations, the use of a double SOI (DSOI) substrate is shown to suppress crosstalk between PISD pixels. The on extra buried oxide layer completely separates the substrate into two parts which shield the movements of charges across the adjacent cells. The impact of top Si thickness and buried oxide thickness is observed.