Effect of low temperature postannealing on the hole density of C δ‐doped GaAs and Al_0.3Ga_0.7As Available to Purchase

In C δ‐doped GaAs and Al_0.3Ga_0.7As grown by metalorganic vapor phase epitaxy using trimethylaluminium as a doping precursor, 20%–50% of the C acceptors are not electrically active due to hydrogen passivation. These hydrogen passivated C acceptors can be activated by low temperature postannealing in the N₂ ambient. The amount of activated C acceptors depends on the postannealing temperature and postannealing time. After ∼10 min postannealing at 530 °C, most of hydrogen passivated C acceptors are activated, leading to a constant hole density with a further increase in postannealing time. At a given postannealing time of 15 min, an increased temperature always activates more hydrogen passivated C acceptors. There is no measurable change in the hole density after 15 min postannealing at temperatures below 450 °C. The activated C acceptors can be re‐passivated by heating the postannealed C δ‐doped (Al,Ga)As to 480 °C in the AsH₃/H₂ ambient but not in the H₂ ambient. The as‐grown C δ‐doped GaAs with much less hydrogen passivation can be grown using the H₂ cooling ambient.