Infrared Localized-Vibrational-Mode Absorption of Ion-Implanted Aluminum and Phosphorous in Gallium Arsenide

Abstract

The localized‐vibrational‐mode absorption of ion‐implanted Al and P in GaAs is observed. The implants were done at room temperature with a flux of ∼3×10¹² ion/cm² sec and fluences of 2.0×10¹⁶, 2.8×10¹⁶, and 3.7×10¹⁶/cm² at 1 MeV. The Δn=1 transition of Al substitutional on the Ga sublattice and P substitutional on the As sublattice are observed, and liquid‐nitrogen‐temperature absorption measurements are made for isochronal anneals from 200 to 900°C. The Al‐implanted GaAs shows an Al_Ga local mode near 362 cm⁻¹ and GaAs implanted with P shows a band near 355 cm⁻¹ similar to melt‐doped crystals, but with increased linewidths. From the integrated absorption, it is estimated that nearly all of the Al and P is Al_Ga and P_As after 900°C anneal, and the site symmetry is approximately tetrahedral.