Ion-etch produced damage on InAs(100) studied through collective-mode electronic Raman scattering

Raman scattering and x-ray photoelectron spectroscopy are used to study the damage induced by low energy Ar+ milling on InAs(100) surfaces. Evidence f or etch-induced lattice damage is obtained even under the mildest condition s employed. Etching at 75 V creates an In-rich; surface and reduces the int ensity of scattering from the unscreened longitudinal optic (LO) phonon in the near-surface region. Etching at higher voltages creates damage states t hat increase the carrier concentration at depths at least as large as the R aman probe depth (similar to 100 Angstrom). Post etch annealing at 500 degr ees C in ultrahigh vacuum restores the LO phonon mode to its original, inte nsity, the carrier concentration to original levels, and a stoichiometric ( In:As = 1:1) surface composition. Etch-induced lattice damage in the near-s urface, region, which is subsequently removed by annealing at optimal tempe ratures, is the only mechanism consistent with all the inelastic light scat tering and composition results. (C) 2000 American Vacuum Society. [S0734-21 1X(00)10201-X].