Micro FET pressure sensor manufactured using CMOS-MEMS technique

Abstract

The fabrication of a micro field effect transistor (FET) pressure sensor using the commercial 0.35 mu m complementary metal oxide semiconductor (CMOS) process and a post-process has been investigated. The pressure sensor is composed of 16 sensing cells in parallel, and each sensing cell includes a suspended membrane and an NMOS. The suspended membrane is the movable gate of the NMOS. The pressure sensor needs a post-process to obtain the suspended membrane after the CMOS process. The post-process employs etchants, to etch the sacrificial layers to release the suspended membrane, and then a low-pressure chemical vapor deposition (LPCVD) parylene is used to seal the etching holes in the pressure sensor. The pressure sensor produces a change in current when applying a pressure to the sensing cells. Experimental results show that the pressure sensor has a sensitivity of 0.022 mu A/kPa in the pressure range of 0-500 kPa. (C) 2007 Elsevier Ltd. All rights reserved.