On-chip High-voltage Silicon Photovoltaic Cell Array Made by a CMOS Post-processed Device Isolation Method for Driving a MEMS Actuator in a Remote Manner

Abstract

A small autonomous device that integrates MEMS, CMOS and photovoltaic (PV) cells has various attractive applications. However, high voltage such as 100 V is often required to drive MEMS actuators, while a single silicon PV cell generates around 0.7 V at maximum. The authors propose a method to fabricate an on-chip high-voltage silicon PV cell device out of standard silicon PV cells for driving a MEMS actuator remotely. The device consists of many PV cells connected in series with suspended bridge wiring formed with a batch post-process. It is compatible with a standard CMOS process, and therefore monolithic CMOS-MEMS-PV integration can be easily achieved. In this paper, the fabrication method and the basic characteristics such as open circuit voltage (V_OC) and short circuit current (I_SC) are shown. The V_OC and I_SC are proportional to the number of cells in series and the area of a cell respectively. Then, a demonstration of remote power feed and control of a MEMS actuator with the proposed PV device is reported.