X-ray and Raman studies of MeV ion-bombarded GaInAs/GaAs

Abstract

We have measured elastic strains and longitudinal optical (LO) phonon shifts in MeV ion-bombarded single layers of (GaIn)As on GaAs(001). We have used He, P, and Cl ions, all in the MeV range, to bombard the samples. Unexpectedly, it is found that the elastic strains initially decrease and the LO phonon frequency initially increases with dose. At higher doses, the strain increases and phonon frequency decreases, as expected for damaged GaAs crystals. For layers with negligible lattice relaxation (i.e., with an in-plane mismatch less than 0.01%), a precipitous perpendicular strain release occurs at a high damage-energy deposition level. The in-plane mismatch for these samples, however, did not change over the same dose range. For 1 μm thick, well-relaxed layers, the ion-beam-induced strain and phonon shift behave similarly to those in ion-damaged bulk GaAs crystals. © 1989.