Carbon‐doped p‐type (0001) plane AlGaN (Al = 6–55%) with high hole density

Abstract

AbstractIn this paper, promising experimental results for the p‐type electrical properties of carbon‐doped (C‐doped) AlGaN are discussed. P‐type conductivity was experimentally achieved in C‐doped (0001) plane AlGaN layers with from a small amount to 55% solid Al composition, but not in (0001) plane GaN. The maximum free hole density (determined by van der Pauw geometry‐Hall effect measurement) achieved for an AlGaN layer with 10% solid Al composition was p = 3.2 × 1018 cm−3. The maximum net ionized acceptor densities (NIAD), $N_{{\rm A}}^{- } - N_{{\rm D}}^{ + } $, which were determined by capacitance–voltage measurement, for AlGaN with 6, 10, 27, and 55% solid Al compositions, were all in the range of (6–7) × 1018 cm−3. Moreover, the electrical activity of the carbon acceptors was estimated to be 55–71% from the NIAD and secondary‐ion microprobe mass spectrometry analysis data on the carbon concentration. A p–n junction was also fabricated using the C‐doped p‐type AlGaN.