Very high carbon incorporation in metalorganic vapor phase epitaxy of heavily doped p-type GaAs

Abstract
Very high C incorporation (≳1020 cm−3) in GaAs was achieved by atmospheric pressure metalorganic vapor phase epitaxy (AP‐MOVPE) using CCl4 as a dopant gas. Hole densities up to p=1.2×1020 cm−3 (at least three times higher than previously reported by MOVPE) were obtained at a growth temperature of 600 °C and a V/III ratio of 2.8. The highest atomic C concentration was 1.5×1020 cm−3. The hole mobilities were ∼50% larger than previously reported. CCl4 was found to suppress the formation of gallium droplets and whisker growth which normally occur under low‐temperature, low V/III ratio growth conditions, allowing the growth of thin (p∼1×1020 cm−3 showed a lattice contraction with Δa/a=−9.3×10−4. Photoluminescence studies indicate a significant band‐gap shrinkage at high doping levels.