Optical techniques for characterizing SI GaAs

Abstract

A number of optical techniques that can be used for the nondestructive characterization of semi-insulating GaAs are described. These techniques include regular photoluminescence, photoluminescence excitation spectroscopy, selective donor–acceptorpair luminescence, electronic Raman scattering, and local vibrational mode absorption for the identification and concentration determination of acceptors. For donors, magneto-photoluminescence can determine the chemical identity and relative concentration of the shallow donors, while for the important deep donor EL2, absorption and bleaching experiments determine the neutral EL2 concentration. The utility of these techniques for routine and reliable characterization of production and developmental GaAs wafers is discussed. The possible extension of these techniques to spatially resolved 2D mapping of GaAs wafers is also discussed.