TEXTURE ANALYSIS OF COGE2 ALLOY-FILMS GROWN HETEROEPITAXIALLY ON GAAS(100) USING PARTIALLY-IONIZED BEAM DEPOSITION

Reflection x-ray pole figure analysis techniques were used to study th e heteroepitaxial relationships of the cobalt germanide CoGe2 to GaAs( 100). The alloy films were grown using the partially ionized beam depo sition technique, in which low energy Ge+ ions are employed to alter t he heteroepitaxial orientation of the CoGe2 deposits. The CoGe2[001](1 00)\\GaAs[100](001) orientation, which has the smallest lattice mismat ch, was found to occur for depositions performed at a substrate temper ature around 280 degrees C and with similar to 1200 eV Ge+ ions. Lower ing the substrate temperature or reducing the Ge+ ion energy leads ro CoGe2)100) orientation domination with CoGe2[100](010)\\GaAs[100](001) and CoGe2[100](001)\\GaAs[100](001). Substrate temperature alone was seen to produce only the CoGe2(100) orientation. For CoGe2(001) films, additional energy was required from Ge+ ions in the evaporant stream. (C) 1997 American Institute of Physics.