High-Voltage Generation in CMOS Photovoltaic Devices by Localized Substrate Removal

This letter reports a localized substrate removal (LSR) process for on-chip electrical isolation to promote the generation of high voltages by backside-illuminated complementary metal-oxide-semiconductor (CMOS) photovoltaic (PV) devices. The proposed four-cell-cascaded CMOS PV module provides an open-circuit voltage of 2.05 V, a short-circuit current of 2.6 mA, and a conversion efficiency of 11% under 40-mW input laser intensity. The proposed LSR approach can also be used for the stacking of additional on-chip PV cells to generate even more voltage without the need for additional processing steps and without compromising device performance. High-voltage CMOS PV modules could be used in voltage-driven microelectronic circuits (>1.8 V) or current-driven light sources (>1 mA) for a variety of applications.