The role of compound formation and heteroepitaxy in indium‐based ohmic contacts to GaAs

摘要

Ohmic contacts to n‐GaAs formed by the heat treatment of In films have been investigated. The widely‐accepted model for ohmic contact formation, involving the establishment of a heavily‐doped layer, fails in this case because In is not a n‐type dopant in GaAs. It is shown that the heat treatment results in the formation of a graded InxGa1-xAs (0≤x≪1) heterojunction. This heterojunction is responsible for the ohmic behavior.