Monolithic integration of a silicon micromotor in combination with the CMOS drive circuit on one chip

Abstract

Since the first working micromotor on silicon was presented 1989, several other research groups demonstrated similar built micromotors, but these were always stand-alone devices without CMOS electronics or other components on the same chip. In this paper we will present a completely CMOS-compatible integrated surface micromachined micromotor, which is monolithically integrated together with the necessary CMOS drive circuit, containing an oscillator, a frequency divider, a divide-by-three counter, and DMOS transistors for the drive circuit on one silicon chip. The fabrication process to generate micromotors and CMOS circuits monolithically on one silicon chip is exactly explained. The process is easily transferable to any other CMOS process line and uses only standard process steps. It can be used as basis for several other MEMS applications for intelligent sensor and actuator systems.