Low resistivity of highly Si-doped n-type Al_0.62Ga_0.38N layer by suppressing self-compensation

Abstract

The lowest resistivity of highly Si-doped Al0.62Ga0.38N was achieved using metalorganic vapor epitaxy. The resistivity strongly depended on the Si concentrations and reached a minimum value of 6.6 × 10−3 Ω cm at a Si concentration of 3.2 × 1019 cm−3, where the carrier concentration was close to the Si one. Above this concentration, luminescence bands around 2.4 eV originating from group-III-vacancy–Si complexes (VIII–nSi) were observed, whereas carrier concentrations and mobilities decreased. Growth conditions that avoid high temperatures and V/III ratios result in suppressed formation of VIII–nSi, playing a key role in achieving low resistivity.