Origin of nonradiative recombination centers in AlGaInP grown by metalorganic vapor phase epitaxy

We report the first concrete evidence that oxygen causes nonradiative deep levels in (Al_x Ga_1–x)_0.5In_0.5P grown by metalorganic vapor phase epitaxy. We doped AlGaInP with O₂ and investigated the oxygen and deep level concentrations by secondary ion mass spectroscopy and isothermal capacitance transient spectroscopy. We confirmed that oxygen causes the D3 (thermal activation energy: E_T ? 1.0 e V for x = 0.7, nonradiative recombination center) and D2 (E_T ? 0.46 e V) levels, which we previously found in undoped AlGaInP. We demonstrate that the oxygen and nonradiative deep level concentrations are significantly reduced at higher growth temperatures, higher PH3 partial pressures, and substrate offset from (100) toward [011].