An Acetone Microsensor with a Ring Oscillator Circuit Fabricated Using the Commercial 0.18 μm CMOS Process

Sensors

Ming-Zhi Yang¹  Ching-Liang Dai¹ 

[1] Department of Mechanical Engineering, National Chung Hsing University, Taichung 402, Taiwan; E-Mail:

关键词: acetone microsensor;    α-Fe₂O₃;    ring oscillator circuit;   

DOI  :  10.3390/s140712735

来源: mdpi

【 摘 要 】

This study investigates the fabrication and characterization of an acetone microsensor with a ring oscillator circuit using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The acetone microsensor contains a sensitive material, interdigitated electrodes and a polysilicon heater. The sensitive material is α-Fe₂O₃ synthesized by the hydrothermal method. The sensor requires a post-process to remove the sacrificial oxide layer between the interdigitated electrodes and to coat the α-Fe₂O₃ on the electrodes. When the sensitive material adsorbs acetone vapor, the sensor produces a change in capacitance. The ring oscillator circuit converts the capacitance of the sensor into the oscillation frequency output. The experimental results show that the output frequency of the acetone sensor changes from 128 to 100 MHz as the acetone concentration increases 1 to 70 ppm.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.