Formation of ‘environmentally friendly’ semiconductor (β-FeSi 2) thin films prepared by ion beam sputter deposition (IBSD) method

Abstract

‘Environmentally friendly’ semiconductor β-FeSi 2 thin films have been prepared by the ion beam sputter deposition (IBSD) method on Si(100) substrate. The difference in crystallinity of the FeSi 2 obtained has been investigated using Fe and Fe–Si targets at various substrate temperatures. When the Fe target was used, highly (100)-oriented β-FeSi 2 films with relatively smooth surfaces were formed at 700°C. On the other hand, such films were scarcely observed when the Fe–Si target was used. Sharp edge grains were observed, which consisted of a mixture of α and β phases or α single phase. In the latter case, α-FeSi 2 is formed at T s above 600°C, which is lower than the conventional transformation temperature for the β→α phase.