Investigation of weak damage in Al0.25Ga0.75As/GaAs by using RBS/C and Raman spectroscopy

The weak damage induced by 0.8 MeV Si ion implantation in the Al0.25Ga0.75A s films epitaxially grown on GaAs substrates was studied by using Rutherfor d backscattering spectrometry/channeling (RBS/C) and Raman spectroscopy. RB S/C spectra measured from the implanted samples showed rather low damage le vel induced by the ion implantation with ion dose from 1 x 10(14) to 5 x 10 (15) cm(-2). The Raman spectra were measured on these samples. Two kinds of phonon modes, GaAs-like and AlAs-like, are observed, which indicate the ex istence of multiple phonon vibrational modes in the epitaxial Al0.25Ga0.75A s films on the GaAs substrate. Compared with the unimplanted sample, the Ra man photon peaks for the implanted sample shift gradually to lower energy w ith the increase of the implantation dose. The strains induced in the impla nted layer were also evaluated from the Raman spectra. The result from high resolution double crystal X-ray diffractometry (HRXRD) also verified the e volution of the strains in the implanted layers. (C) 2001 Elsevier Science B.V. All rights reserved.