LOCAL STRESS MEASUREMENTS IN LATERALLY OXIDIZED GAAS ALXGA1-XAS HETEROSTRUCTURES BY MICRO-RAMAN SPECTROSCOPY/

Lattice deformation induced in surface GaAs layers by the selective la teral oxidation of buried AlxGa1-xAs layers was determined from the en ergy shift of the GaAs phonon line in Raman spectra excited with a foc used laser beam. The procedure included a correction for the laser bea m induced heating effects, The surface GaAs laver was found under smal l tensile stress in the oxidized regions of our samples with respect t o the unoxidized regions. The deformation is 8 x 10(-4) and is the sam e, within experimental error, for heterostructures incorporating pure AlAs layers or Al0.98Ga0.02As. Strong differences in Raman efficiency, as well as in photoluminescence efficiency, were observed for differe nt samples, which are discussed in terms of the GaAs/oxide interface n onradiative recombination efficiency. (C) 1997 American Institute of P hysics. [S0003-6951(97)04043-6].