Acceptor and Donor Doping of AI↓(x)Ga↓(1- x)N Thin Film Alloys Grown on 6H-SiC(0001) Substrates via Metalorganic Vapor Phase Epitaxy

摘要

Thin films of Si-doped Al↓(Χ)Ga↓(1-Χ)N (0.03≤ x ≤ 0.58) having smooth surfaces and strong near-band edge cathodoluminescence were deposited at 0.35-0.5μm/h on on-axis 6H-SiC(0001) substrates at 1100℃using a 0.1 μm A1N buffer layer for electrical isolation. Alloy films having the compositions of A1↓(0.08)Ga↓(0.92)N and A1↓(0.48)Ga↓(0.52)N exhibited mobilities of 110 and 14 cm↑(2)／V.s at carrier concentrations of 9.6 × 10↑(18) and 5.0 × 10↑(17)cm↑(-3), respectively. This marked change was due primarily to charge scattering as a result of the increasing Al concentration in these random alloys. Comparably doped GaN films grown under similar conditions had mobilities between 170 and -350 cm↑(2)／V.s. Acceptor doping of Al↓(Χ)Ga↓(1-Χ)N for x ≤ 0.13 was achieved for films deposited at 1100℃. No correlation between the O concentration and p-type electrical behavior was observed.