CHEMICAL BEAM EPITAXY OF COGA ON GAAS USING GAET3 AND CPCO(CO)(2) AS DUAL ORGANOMETALLIC SOURCES

Low temperature epitaxial growth of beta-CoGa thin films was carried o ut on (100)GaAs by chemical beam epitaxy using CpCo(CO)(2) and GaEt3 a s separate metalorganic sources. The film composition and the lattice mismatch on (100)GaAs may be adjusted by controlling the molecular bea m pressure ratio. Typically, the epitaxial relationship [100](001)CoGa / /[100](001)GaAs was observed at 633 K for a ratio CpCo(CO)(2):GaEt3 = 3:1. Annealing experiments have shown that CBE CoGa/GaAs interfaces are thermally stable until ca. 873 K and start to react with the subst rate only from this temperature to form CoAs. This work demonstrates t hat CoGa is a good candidate for stable metal contacts on GaAs and emp hasizes the promising suitability of CBE for the production of metal/I II-V heterostructures.