Formation of a Double-Hetero Si/CoSi2/Si Structure Using Molecular Beam and Solid Phase Epitaxies

Abstract

Hetero- and homostructures of Si/silicide, Si/Si and Si/silicide/Si are formed using molecular beam epitaxy (MBE) and solid phase epitaxy (SPE). Optimum conditions for forming the double heterostructure are discussed based on such experimental results that single crystalline NiSi2, CoSi2 and Pd2Si films are formed on (111)Si substrates but not on (100) or (110)Si. From ion channeling and backscattering measurements, it has been shown that good Si films containing no Co atoms can be epitaxially grown on the Si(111)/CoSi2 structure by MBE at temperatures around 500 °C or by SPE at temperatures around 1000 °C. It has also been shown that NiSi2 is inadequate as an intermediate silicide in the double heteroepitaxy, since a large amount of Ni atoms in the Si(111)/NiSi2 structure moves to the surface during Si deposition in MBE.