Epitaxial CoSi2 formation using an oxynitride buffer layer

Abstract

We investigated the epitaxial growth of CoSi2 (100) on an Si (100) substrate using a modified oxide mediated epitaxy (OME) method to overcome the disadvantages of the OME method. These disadvantages are sensitivity of Co films to contamination by oxygen and the need for reiterating the film growth process to obtain thicker films. To solve these problems, nitrogen atoms were incorporated into chemically grown oxide (SiOx) by NH3 plasma treatment prior to the deposition of a Co film on the oxynitride buffer layer using the metal organic chemical vapor deposition (MOCVD) method. Subsequently, ex situ rapid thermal annealing was performed to grow Co-silicide at a temperature between 400 °C and 700 °C for 1 min. The results show that the diffusion of Co was effectively controlled by the oxynitride buffer layer without the formation of additional SiOx in between Co and Si. Our findings indicate that by using an oxynitride buffer layer, CoSi2 films can be grown epitaxially despite the fact that the initial Co film was exposed to oxygen.