Epitaxial growth of AlGaN/GaN high-electron mobility transistor structure on diamond (111) surface

Abstract

Epitaxial growth of an AlGaN/GaN high-electron mobility trainsistor (HEMT) structure on a diamond (111) substrate was investigated. Due to the misorientation of the diamond (111) surface, the AlGaN/GaN HEMT structure showed the macro-step surface. Using diamond surfaces with two different misorientation angles (3 and 0.5°), we found that the one with the small misorientation angle is effective for obtaining a flat AlGaN/GaN HEMT surface. Threading dislocation density of the AlGaN/GaN HEMT structure grown on the diamond (111) surface was evaluated from crosssectional transmission electron microscope images. The densities of pure-screw-, pure-edge- and mixed-type threading dislocation were 0:3 × 10 9, 4:1 × 10 9, and 4:5 × 10 9 cm -2, respectively. The AlGaN/GaN HEMT eptaxially grown on the diamond (111) substrate showed the maximum drain current of 800mA/mm with little self-heating effect. © 2012 The Japan Society of Applied Physics.