Capacitive Micro Pressure Sensor Integrated with a Ring Oscillator Circuit on Chip

Sensors

Ching-Liang Dai¹  Po-Wei Lu¹  Chienliu Chang² 

[1] Department of Mechanical Engineering, National Chung Hsing University, Taichung, 402, Taiwan; E-Mail:;Corporate R&D Headquarter, Canon Inc., Tokyo 146-8501, Japan; E-Mail:

关键词: micro pressure sensors;    ring oscillators;    CMOS-MEMS;   

DOI  :  10.3390/s91210158

来源: mdpi

【 摘 要 】

The study investigates a capacitive micro pressure sensor integrated with a ring oscillator circuit on a chip. The integrated capacitive pressure sensor is fabricated using the commercial CMOS (complementary metal oxide semiconductor) process and a post-process. The ring oscillator is employed to convert the capacitance of the pressure sensor into the frequency output. The pressure sensor consists of 16 sensing cells in parallel. Each sensing cell contains a top electrode and a lower electrode, and the top electrode is a sandwich membrane. The pressure sensor needs a post-CMOS process to release the membranes after completion of the CMOS process. The post-process uses etchants to etch the sacrificial layers, and to release the membranes. The advantages of the post-process include easy execution and low cost. Experimental results reveal that the pressure sensor has a high sensitivity of 7 Hz/Pa in the pressure range of 0–300 kPa.

【 授权许可】

CC BY   
© 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.