Combined positron lifetime measurements and Doppler broadening spectroscopy, using slow positrons, were combined in order to investigate the open-volume defects which were created by cutting wafers from ingots by using a diamond saw cutter. It was found, using step-by-step polishing, that the depth distribution had a wedge-like profile. The depths and concentrations of the defects which were introduced by the saw depended upon the advance of the saw blade. Isochronal annealing was used to study the thermal stability of the observed defects. The positron lifetime of the predominant open-volume defect was estimated to be greater than 330ps. It was concluded that vacancy aggregates which consisted of at least 2 vacancies were created by the sawing.

Determination of the defect depth profile after saw-cutting of GaAs wafers measured by positron annihilation F.Börner, S.Eichler, A.Polity, R.Krause-Rehberg, R.Hammer, M.Jurisch: Journal of Applied Physics, 1998, 84[4], 2255-62