Raman probing of thermal damage depth profile in annealed GaAs

Raman scattering has been used to get information on the depth profile of both lattice damage and solid arsenic formation in gallium arsenide annealed at different temperatures. Measurements of Raman peak intensity ratio of GaAs transverse to longitudinal optical phonons as a function of exciting wavelength with a different penetration depth of the light gave information on the depth profile of the chemical and structural disorder in the gallium arsenide lattice. Moreover, measurements of the arsenic A(1g) and E-g phonon mode frequencies as a function of temperature showed that the arsenic formed in the vicinity of the surface is crystalline and submitted to very high temperature-dependent tensile stresses, with values ranging from 1.5 GPa at 300 K until 2.8 GPa at 10 K. On the other hand, the analysis of selection rules, phonon frequency, and linewidth indicates a strain-free and misoriented GaAs matrix. (C) 1998 American Institute of Physics. [S0021-8979(98)07124-2].