Growth and Properties of Intentionally Carbon‐Doped GaN Layers

Abstract

Abstract Carbon‐doping of GaN layers with thickness in the mm‐range is performed by hydride vapor phase epitaxy. Characterization by optical and electrical measurements reveals semi‐insulating behavior with a maximum of specific resistivity of 2 × 10 10 Ω cm at room temperature found for a carbon concentration of 8.8 × 10 18 cm −3 . For higher carbon levels up to 3.5 × 10 19 cm −3 , a slight increase of the conductivity is observed and related to self‐compensation and passivation of the acceptor. The acceptor can be identified as C N with an electrical activation energy of 0.94 eV and partial passivation by interstitial hydrogen. In addition, two differently oriented tri‐carbon defects, C N ‐a‐C Ga ‐a‐C N and C N ‐a‐C Ga ‐c‐C N , are identified which probably compensate about two‐thirds of the carbon which is incorporated in excess of 2 × 10 18 cm −3 .