Lateral PIN Photodiode with Germanium and Silicon Layer on SOI Wafers

Abstract

Here, it has been verified through numerical simulations calibrated to experimental data the changes that the insertion of a germanium layer can bring to the electrical power generation of a silicon solar cell. The studied device is a lateral PIN photodiode embedded in a wafer with SOI (Silicon-On-Insulator) technology as part of a CMOS (Complementary Metal Oxide Semiconductor) circuit. The insertion of a germanium layer on top or below a silicon PIN diode has been considered. Results showed that different semiconductor characteristics (bandgap, mobility, and absorption coefficients) result in a general improvement in the solar cell performance, therefore allowing a better understanding of the phenomena that occur in the photogeneration of a cell with a heterojunction between germanium and silicon.