High electron mobility AlGaN/GaN heterostructure on (111) Si

Room-temperature Hall mobilities exceeding 900 cm(2)/V s are obtained for A lGaN/GaN heterostructures on (111) Si by single-temperature flow modulation organometallic vapor phase epitaxy. Thin pseudomorphic AlGaN top layers ex hibit a 1.5 nm surface roughness and induces a two-dimensional electron gas sheet carrier concentration of 1.0x10(13) cm(-2). The GaN buffer layer has a background carrier concentration of 1.0x10(15) cm(-3), 130 arcsec x-ray diffraction full width at half maximum, and a low-temperature photoluminesc ence linewidth of 10 meV. An AlN nucleation layer provides static electrica l isolation between the AlGaN/GaN and the conducting Si substrate. Large cr ack-free areas of high-crystalline-quality epitaxial material are obtained and have been successfully used for transistor fabrication. (C) 2000 Americ an Institute of Physics. [S0003-6951(00)03406-9].