EBIC INVESTIGATION OF ALPHA-DISLOCATION AND BETA-DISLOCATION IN GAAS

Electron beam induced current (EBIC) microscopy is applied for studyin g the recombination activity of alpha and beta dislocations introduced by micro-indentation in n-type GaAs. Quantitative measurements of EBI C contrast profiles across several tens of single 60-degrees dislocati ons reveal a distinct difference between the contrast values of the tw o dislocation types. The same difference observed in various crystals and at dislocations introduced at various temperatures provides eviden ce for the recombination activity associated with the core electron st ates of dislocations. From diffusion-length measurements in a dislocat ed region the reduced minority carrier lifetime at alpha dislocations of the order of 10(-12) S is estimated.