Impurity Transfer in GaAs Vapor Growth and Carrier-Concentration Profiles of the Grown Films

Abstract

Doped and undoped GaAs films have been grown epitaxially on semi-insulating or heavily doped n-type (100) plane substrates by the AsCl₃/H₂ vapor transport method. Doped GaAs single crystals were used as source materials for doped films, and Ga source was used for undoped films. The carrier-concentration of films grown from Te-doped source material varies from 2 to 11 times that of the source GaAs, depending on the growth condition. The carrier-concentration of the films grown from Sn-doped source material agrees with that of the source GaAs, without depending on the temperature difference between the source and substrate. Ge is doped into films as donors, but Si is not doped at all. The carrier-concentration profiles of the films grown on heavily Te or S-doped substrates are strongly affected by autodoping from the substrates. While in the case of Si or Sn-doped substrates autodoping is not observed.