Impedance spectroscopic study of beta-Ga2O3/O-2 interaction

Impedance spectroscopy was used to study the oxygen/oxide-semiconductor int eraction mechanism using sputtered beta-Ga2O3/SiO2/Al2O3 and beta-Ga2O3/BeO thin-layer sensor structures between 578 and 850 degrees C. The total samp le resistance was composed of its bulk (R-b) and its grain boundary resista nce (R-gb). While for the beta-Ga2O3/BeO sample R-gb is dominant in the ent ire temperature range, for the beta-Ga2O3/SiO2/Al2O3 structure at higher te mperatures it roughly equals R-b The adsorption of oxygen influenced rather the grain boundary resistance than the bulk resistance. The oxygen sensiti vity of beta-Ga2O3 proved to be frequency dependent; applying a certain fre quency it exceeded the de sensitivity. (C) 1999 The Electrochemical Society . S0013-4651(95)08-014-8. All rights reserved.