INVESTIGATION OF STABILITY OF GAAS METAL ELECTRON SEMICONDUCTOR FIELD-EFFECT TRANSISTOR GATE CONTACTS BY HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY ANALYSIS

The structure of GaAs metal/electron/semiconductor field effect transi stor (MESFET) gate contacts has been investigated by high resolution t ransmission electron microscopy (TEM). A specific technique has been u sed successfully to prepare thin and proper cross-sections of specific regions within GaAs devices. A significant defect has been observed a t the periphery of the recessed gate, which indicates the presence of a non-passivated region of the active layer surface. The presence of a n amorphous layer at the gate metallization-GaAs interface has been re vealed by a high resolution observation. These structural anomalies ha ve been correlated with parasitic effects of the I-V Schottky gate con tact characteristics.