USE OF ZINC DIFFUSION INTO GAAS FOR DETERMINING PROPERTIES OF GALLIUMINTERSTITIALS

The fast diffusion of Zn into GaAs has recently been attributed to a m inor fraction of Zn interstitials changing over to Ga sites thereby pr oducing interstitial Ga (I-Ga). This kick-out reaction provides the po ssibility to determine I-Ga transport properties from Zn diffusion exp eriments in virtually perfect GaAs but previous attempts were frustrat ed by diffusion-induced generation of microstructural defects acting a s I-Ga sinks. The present study prevents such defect formation by util izing Zn-doped GaAs powder as diffusion source. Measured two-stage pro files show that under these conditions Zn diffusion at 906 degrees C i s controlled by I-Ga(3+) in addition to I-Ga(2+). Analysis of the prof iles yield quantitative data on Ga- and Zn-related diffusivities, conc entrations of I-Ga as well as the corresponding electronic transition energy.