Scanning Photovoltage Technique for High Resolution Non-Destructive Characterization of Semiconductor Wafers

摘要

Near-surface defects in semiconductor wafers have a primary influence upon device properties, both, the yield and radiation hardness. In phase I of this program, a scanning photovoltage (SPV) technique was experimentally evaluated for the high-resolution, non-destructive identification and mapping of near-surface defects in wafers. The SPV technique shows promise of being useful for this purpose in semi-insulating materials such as GaAs, silicon-on-sapphire and InP. All the goals in the Phase I program were met; experimental apparatus was developed and the differential SPV signal correlated with surface dislocation networks in GaAs wafers. The results strongly support the development and further evaluation of the SPV techniques. The apparatus utilizes an Ar-ion scanning laser system with a programmable x-y table and a focussed laser beam. A photovoltage signal is measured due to the modulated laser beam. (Author)