METAL GAN SCHOTTKY BARRIERS CHARACTERIZED BY BALLISTIC-ELECTRON-EMISSION MICROSCOPY AND SPECTROSCOPY/

Ballistic-electron-emission microscopy (BEEM) and spectroscopy have be en used to characterize the Pd/GaN and Au/GaN interfaces. BEEM spectra yield a Schottky barrier height for Au/GaN of similar to 1.05 eV that agrees well with the highest values measured by conventional methods. For both Pd and An, a second threshold is observed in the spectra at about 0.2-0.3 V above the first threshold. Imaging of these metal/GaN interfaces reveals transmission in nearly all areas, although the magn itude is small and spatially varies. Attempts to perform BEEM measurem ents on other GaN material have resulted in no detectable transmission in any areas, even at voltages as high as 3.5 V. (C) 1998 American Va cuum Society.