Design and Fabrication of Silicon PiezoMOS Transistors for Applications on MEMS

This article describes the project, manufacturing and characterization of silicon piezoMOS transistors made entirely in Brazil. PMOS transistors were designed observing some rules to maximize the piezoMOS effect. A back-side bulk micromachining post-process based on KOH etching was used to make a membrane which was aligned with the piezo transistors on the front side. Experimental results show that the drain current variation amounts for 8% due to a differential pressure of 25 psi applied on opposite sides of the silicon membrane. PiezoMOS transistors can be widely used in MEMS as a low-power alternative comparing to piezo resistors.