Impedance spectroscopic and secondary ion mass spectrometric studies of beta-Ga2O3/O-2 interaction

In the present work the impedance spectroscopy and secondary ion mass spect rometry (SIMS) were used to study the oxygen/beta -Ga2O3 interaction betwee n 578 and 835 degreesC. The overall resistance of the beta -Ga2O3 is compos ed of the bulk resistance and the grain boundary resistance. If oxygen is p resent, dominantly the characteristics of the space charge region - formed at the grain boundaries - change. The mechanism of the bulk conduction is u nchanged between 578 and 835 degreesC, however, the processes determining t he grain boundary resistance are different above and below similar to 700 d egreesC. At low temperatures the formation and adsorption of O-2(-) ions is probable, while at higher temperatures the presence of O- ions is dominant on the grain boundaries. (C) 2001 Elsevier Science B.V. All rights reserve d.