Development of AlN/diamond heterojunction field effect transistors

• Published in: Diamond and related materials Vol. 24; pp. 206 - 209
• Main Authors: Imura, Masataka, Hayakawa, Ryoma, Ohsato, Hirotaka, Watanabe, Eiichiro, Tsuya, Daiju, Nagata, Takahiro, Liao, Meiyong, Koide, Yasuo, Yamamoto, Jun-ichi, Ban, Kazuhito, Iwaya, Motoaki, Amano, Hiroshi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2012; Elsevier
• Subjects: Aluminum nitride; Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Contact; Contact resistance, contact potential; Cross-disciplinary physics: materials science; rheology; Density; Devices; Diamond; Diamonds; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Electronics; Exact sciences and technology; Field effect transistor; Field effect transistors; Fullerenes and related materials; diamonds, graphite; Heterojunctions; Materials science; Nitrides; Other semiconductors; Physics; Semiconductor devices; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Specific materials; Transistors; Field effect transistor; Nitrides; Diamond; Aluminum nitride; Field effect transistors; Diamonds; Plasma assisted processing; Contact resistance; Epitaxial layers; Hole density; Aluminium nitride; Mechanical properties; Aluminium; Adhesion; Carbon; Heat treatments; III-V compound; Ammonia; p channel; MOVPE method; Growth mechanism; Heterojunctions; Heterojunction field effect transistor; Carrier density; III-V semiconductors; X-ray photoelectron spectra; Tribology
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2012.01.020

AlN/diamond heterojunction field effect transistors with p-channel and normally-on depletion mode are developed, and the device performance is improved by reducing the contact resistances at source and drain contacts reported previously. The heterojunction structure is constructed from a c-axis-oriented AlN epilayer grown on oxygen-terminated (111) diamond substrate by metal-organic vapor phase epitaxy at temperatures as high as 1250°C. Thermal treatment in the mixed hydrogen (H2) and ammonia atmosphere just before AlN growth improves the AlN adhesion to diamond surface. In addition, this treatment simultaneously produces a much larger surface hole-carrier density than that obtained by conventional H2-plasma treatment. X-ray photoelectron spectroscopy reveals the existence of carbon-nitrogen bonds at the diamond surface, and these may be responsible for such a large hole density. These results are promising in relation to new opportunities for developing diamond-based power electronic devices.