Metal-insulator-semiconductor Schottky barrier structures fabricated usinginterfacial BN layers grown on GaN and SiC for optoelectronic device applications

Metal-insulator-semiconductor Schottky barrier structures on GaN and 6H-SiC using highly stable interfacial BN layers have been investigated. As repor ted earlier, such structures fabricated with Ti contacts are capable of wit hstanding up to 350 and 600 degrees C when based on 6H-SiC and GaN, respect ively. In this work we fabricated diode structures using interfacial BN lay ers and optically transparent Au contacts. Visible-blind photosensitive str uctures on GaN and 6H-SiC and prebreakdown light-emitting diode (LED) struc tures on 6H-SiC have been characterized. The radiant and spectral sensitivi ties of the photosensitive structures were measured in the range of 200-400 nm. The potential barrier heights determined from photoresponse measuremen ts were 2.7 and 2.88 eV for GaN- and SiC-based samples, respectively. The s pectrum of 6H-SiC and p-GaN-based prebreakdown LED structures measured thro ugh transparent Au electrodes extended to the ultraviolet region. The optic al emission power of the 6H-SiC-based LED structures measured in the range 200-1100 nm saturated to about 10(-8) W at current densities close to 200 A /cm(2). Prospects for applications of the diode structures described in adv anced visible-blind optoelectronic sensors are discussed. (C) 1999 American Vacuum Society. [S0734-2101(99)15804-4].