Impact of residual carbon on two-dimensional electron gas properties in AlxGa1-xN/GaN heterostructure

Abstract

High tuneability of residual carbon doping is developed in a hot-wall metalorganic chemical vapor deposition reactor. Two orders of temperature-tuned carbon concentration, from ∼2 × 1018 cm-3 down to ∼1 × 1016 cm-3, can be effectively controlled in the growth of the GaN buffer layer. Excellent uniformity of two-dimensional electron gas (2DEG) properties in AlxGa1-xN/AlN/GaN heterostructure with very high average carrier density and mobility, 1.1 × 1013 cm-2 and 2035 cm2/V·s, respectively, over 3" semi-insulating SiC substrate is realized with the temperature-tuned carbon doping scheme. Reduction of carbon concentration is evidenced as a key to achieve high 2DEG carrier density and mobility. © 2013 AIP Publishing LLC.