GaAs wafer investigation by near-infrared transmission and photoluminescence topography techniques

Two optical topographical methods for homogeneity control of GaAs wafers are presented. The first one (NIRtop) monitors the transmission of near infrared light, while the other one (PLtop) records the room temperature photoluminescence. The topograms are displayed as false colour pictures of high resolution. By comparison a remarkable resemblance for both methods is found when applied to undoped s.i. LEC material. The two methods in combination are very useful for the inspection of surface quality and of various technological processes as annealing, ion implantation, activation and epitaxial growth of thin films. (IAF