Ion beam induced epitaxial crystallisation of silicon

It is shown that epitaxial crystallisation of amorphous silicon layers can be induced by irradiating samples with energetic light ions at temperatures in the range 673-723 K. This epitaxial process is shown not to be a consequence of macroscopic beam heating. Under certain irradiation conditions Rutherford backscattering/channeling analysis suggests that the regrown silicon is nearly perfect single crystal but TEM analysis, while confirming epitaxial growth, reveals the presence of extended defects which result from the elevated temperature helium bombardment. Evidence is presented to support the view that ion beam induced epitaxy is a consequence of mobile, ion irradiation induced defects created at, or near, the crystal-amorphous interface.