Surface effects on breakdown characteristics of GaAs bulk diodes

Effects of peripheral-surface damages on breakdown characteristics of epitaxial GaAs bulk diodes were investigated experimentally. Critical voltages for switching from a high-voltage saturating-current state to a high-current low-voltage state were measured on a number of mechanically diced cubic-type elements and on chemically etched mesa-type elements. It was found that the switching voltages of the mesa-type diodes were much higher and more uniform than those of the cubic type. The difference in the switching voltages between the two types is ascribed to the peripheral-surface damages produced on the cubic-type elements during wire saw cutting. It was concluded that the elimination of the peripheral surface damages is important to obtain GaAs bulk diodes of high reliability.