Role of Interface-States in the Reverse Bias Aging of GaAs Schottky Barriers

ABSTRACTForward bias capacitance has been used to examine the Au/W/GaAs and Au/Pt/Ti/GaAs Schottky barriers present in power microwave MESFET devices to see if interface-state generation plays any role in the previously reported reverse bias barrier height aging process. If a constant carrier capture cross-section is assumed, forward bias capacitance has shown that for samples strongly susceptible to aging (i.e. the Au/W/GaAs samples in this study) interface-state generation is taking place during the aging process. The validity of the constant capture cross section assumption has been tested by examining the I–V properties. For those samples whose reverse I–V properties were not dominated by thermionic-field emission, similar increases in interface-state densities were evaluated from the I–V characteristics for the degraded samples.