Abstract

Our computerized Hall effect and Deep Level Transient Spectroscopy (DLTS) set-ups permitted the systematic analysis of the interactions of the vacancies or defects in GaAs. The generally accepted model of EL2 antisite complex in As-rich GaAs was modified by the introduction of a deep lying off-stoichiometry introduced acceptor level. This modification was invoked by our analysis of a large number of experimentally observed data using the multilevel impurity model. It is of interest to mention here that the quantitative interpretation of the measured transport properties of semiconducting and semi-insulating arsenic-rich GaAs crystals requires a phase-extent induced Ga vacancy concentration of V_Ga = 3 × 10¹⁷ cm^–3. This is the value deduced for Gallium defects in Silicon-doped GaAs from Positron lifetime measurements. Thus, multilevel impurity model based on the Shockley curves seems to be supported.

© 1994 IEEE