Hydrogen sensing properties of a Pt-oxide-Al0.24Ga0.76As high-electron-mobility transistor -: art. no. 112103

The interesting hydrogen sensing performances of a Pt-oxide-AlGaAs (MOS) high electron mobility transistor (HEMT) are studied and demonstrated. The effects of hydrogen adsorption on device performances such as the threshold voltage shift Delta V-th, drain saturation current variation Delta I-DS, and transient response are presented. Delta V-th and Delta I-DS decreased with increasing operating temperature. This suggests that, at higher temperature, less hydrogen atoms diffuse through the Pt bulk and reach the interface between the Pt metal and oxide layer resulting from the relatively faster formation rate of hydroxyl on the Pt surface. The response curves of the studied Pt-AlGaAs MOS HEMT show various profiles at different temperatures. The influences of hydrogen concentration and temperature on the interface sites occupied by adsorbed atoms are also studied. (C) 2005 American Institute of Physics.