Common structure in amorphised compound semiconductors

Extended X-ray absorption fine structure has been utilised to determine the structural parameters of the amorphous III-V semiconductors GaP, GaAs, InP and InAs. The amorphous phase was formed by ion implantation to inhibit preparation-specific artefacts associated with the alternative fabrication techniques of sputtering and evaporation. Relative to crystalline standards, increases in bond length and Debye-Waller factor were apparent for all materials with a slight reduction in coordination number (3.8-4 atoms). Similarly, homopolar bonding in the amorphous phase was measurable for all materials. For example, In-In bonding in amorphous InP comprised similar to18% of the total In bonds and demonstrated the necessity of a ring distribution containing both even and odd members. (C) 2002 Elsevier Science B.V. All rights reserved.