Light emission and burnout characteristics of GaAs power MESFET´s

In order to obtain information on the field distributions and weak places of GaAs power MESFET´s, the light emission and pulse burnout characteristics were investigated. Their dependence on the drain structure was also studied. The light emission occurs at the drain edge of the active region when the gate bias is zero volt, slightly changing its place depending on the drain structure. The drain edge of the epitaxial layer was also damaged by the pulse burnout experiments at zero gate bias. When the gate bias is increased, the light emission at the drain edge decreases rapidly until the gate Schottky breaks down and begins to give the light emission at the gate edge. The pulse burnout experiments suggest that the burnout initiates inside of the active or buffer epitaxial layer when the gate bias is near the pinchoff voltage.