High sensitive hydrogen sensor by Pd/oxide/InGaP MOS structure

摘要

Experimental formation of LPO (liquid phase oxidation)-grown InCaP native oxide near room temperature (similar to 60 degrees C) is demonstrated. A high oxidation rate is obtained and checked by SEM and AES. The native oxide is determined to be composed of InPO4 and Ga2O3, analyzed by the results of XPS measurement. Due to the presence of the excellent quality of InGaP native oxide, high hydrogen (H-2) sensitivity in output current of a Pd/oxide/InCaP MOS Schottky diode is observed. Under the applied voltage of -1 V and 50 ppm H-2/air, a high sensitivity of 1090 is obtained. An obvious variation of output current and a short response time due to the exposure to different H2 concentration are also achieved. For example, the adsorption (tau(a)) and desorption (tau(b)) time constants under 50 ppm H-2/air are 2.3 s and 2.7 s, respectively.