A new Pd-oxide-Al/0.3/Ga/0.7/As MOS hydrogen sensor

• Published in: IEEE electron device letters 2003-06, Vol.24 (6), p.390-392
• Main Authors: Lu, Chun-Tsen, Lin, Kun-Wei, Chen, Huey-Ing, Chuang, Hung-Ming, Chen, Chun-Yuan, Liu, Wen-Chau
• Format: Article
• Language: English
• ISSN: 0741-3106
• DOI: 10.1109/LED.2003.813354

A new and interesting Pd-oxide-Al/0.3/Ga/0.7/As MOS hydrogen sensor has been fabricated and studied. The steady-state and transient responses with different hydrogen concentrations has been measured at various temperatures. Based on the large Schottky barrier height and presence of oxide layer, the studied device exhibits a high hydrogen detection sensitivity and wide temperature operating regime. The studied device exhibits the low-leakage current and obvious current changes when exposed to hydrogen-contained gas. Even at room temperature, a very high hydrogen detection sensitivity of 155.9 is obtained when a 9090 ppm H(2)/air gas is introduced. Furthermore, when exposed to hydrogen-contained gas at 95 deg C, both the forward and reverse currents are substantially increased with increased hydrogen concentration. In other words, the studied device can be used as a hydrogen sensor under the applied bidirectional bias. Under the applied voltage of 0.35 V and 9090 ppm H(2)/air hydrogen ambient, a fast adsorption response time about 10 s is found. The transient and steady-state characteristics of hydrogen adsorption are also investigated.