P- and N-Type Doping of GaN and AlGaN Epitaxial Layers Grown by Metalorganic Chemical Vapor Deposition

摘要

Mg- and Si-doped GaN and AlGaN films were grown by metalorganic chemical vapor deposition and characterized by room-temperature photoluminescence and Hall-effect measurements. We show that the p-type carrier concentration resulting from Mg incorporation in GaN:Mg films exhibits a nonlinear depen- dence both on growth temperature and growth pressure. For GaN and AlGaN, n-type doping due to Si incorporation was found to be a linear function of the silane molar flow. Mg-doped GaN layers with 300K hole concentrations p ～ 2 × 10~18 cm~-3 and Si-doped GaN films with electron concentrations n ～ 1 × 10~19 cm~-3 have been grown. N-type Al_0.10Ga_0.90N:Si films with resistivities as low as p ～ 6.6 × 10~-3 Ω-cm have been measured.