Author(s): Sun, Jianwen; Zhan, Teng; Sokolovskij, Robert; Liu, Zewen; Sarro, Pasqualina M.; Zhang, Guoqi

Source: IEEE SENSORS JOURNAL Volume: 21 Issue: 15 Pages: 16475-16483 DOI: 10.1109/JSEN.2021.3082205 Published: AUG 1 2021

Abstract: Based on our proposed precision two-step gate recess technique, a suspended gate-recessed Pt/AlGaN/GaN heterostructure gas sensor integrated with a micro-heater is fabricated and characterized. The controllable two-step gate recess etching method, which includes O-2 plasma oxidation of nitride and wet etching, improves gas sensing performance. The sensitivity and current change of the AlGaN/GaN heterostructure to 1-200 ppm NO2/air are increased up to about 20 and 12 times compared to conventional gate device, respectively. The response time is also reduced to only about 25 % of value for conventional device. The sensor has a suspended circular membrane structure and an integrated micro-hotplate for adjusting the optimum working temperature. The sensitivity (response time) increases from 0.75% (1250 s) to 3.5% (75 s) toward 40 ppm NO2/air when temperature increase from 60 degrees C to 300 degrees C. The repeatability and cross-sensitivity of the sensor are also demonstrated. These results support the practicability of a high accuracy and fast response gas sensor based on the suspended gate recessed AlGaN/GaN heterostructure with an integrated micro-heater.

Accession Number: WOS:000679541000008

ISSN: 1530-437X

eISSN: 1558-1748

Full Text: https://ieeexplore.ieee.org/document/9436778