Comparison of the self-cleaning effects and electrical characteristics of BeO and Al2O3 deposited as an interface passivation layer on GaAs MOS devices

Abstract

Beryllium oxide (BeO) is a promising dielectric because of its high energy bandgap (10.6 eV) and short Be and O atom bonds and its excellent electrical insulating characteristics and high thermal stability. In a previous study, the authors showed that BeO grown by atomic layer deposition (ALD) as a gate dielectric on Si and GaAs substrates has excellent electrical and physical characteristics. In this work, we used monochromatic x-ray photoelectron spectroscopy (XPS) and electrical analysis to compare the ability of ALD BeO and Al2O3 to reduce the surface oxide on GaAs substrates. High resolution XPS shows that the BeO reduced surface oxide more efficiently than Al2O3 and that the capacitance-voltage characteristics correspond with the XPS results. In addition, ALD BeO exhibits less interfacial oxide growth after post-deposition annealing and a more efficient suppression of the leakage current.