Structural Characteristics of CoGe2 Alloy Films Grown Heteroepitaxially on GaAs(100) Substrates Using the Partially Ionized Beam Deposition Technique

The Partially ionized beam (PIB) deposition technique was used to deposit CoGe2 thin films heteroepitaxially on GaAs(100) substrates in a conventional vacuum. For the CoGe2(001)/GaAs(100) system, which leads to an Ohmic contact, a substrate temperature of 280°C and ∼1200 eV Ge+ ions are required. Reducing the ion energy or lowering the substrate temperature both produce a different orientation in the films. Films deposited at 280°C with a zero accelerating potential for the ions, and those deposited at 200°C with -1200 eV Ge+ ions result in a CoGe2(100)//GaAs(100) type orientation domination, leading to rectifying behavior.