Optical reflectance: a sensitive nondestructive method for detecting surface damage in crystalline GaAs and other semiconductors

Optical reflectance has been demonstrated to be a very sensitive nondestructive method to determine the degree of surface damage for crystalline germanium and silicon semiconductors. Application of this method to measure the surface quality of gallium arsenide (GaAs) is reported here. For GaAs, the optical reflectance at 5.1 eV can be used to determine the degree of surface damage, i.e., the surface quality. For a series of GaAs substrates polished with selected abrasives, the reflectance is shown to decrease with increasing size of the abrasive. As an independent method of determining the degree of surface damage, the photoluminescence spectrum of GaAs has been measured and correlated with the optical reflectance. Overall, the optical reflectance is shown to be a nondestructive, simple, fast, and sensitive measurement, which is readily adaptable to quality control inspection of GaAs and other III-V semiconductor surfaces.