Epitaxial growth of CoSi2 layer on a Si(100) substrate using a CoNx interlayer deposited by reactive sputtering

Abstract

A new method for growing an epitaxial CoSi2 layer has been studied. In the proposed approach, CoNx film is used as an interlayer. From the Co/CoNx/Si structure, a uniform CoSi2 layer was epitaxially grown on a Si (100) substrate. The CoNx films were deposited by reactive sputtering in Ar + N-2 gas. Two amorphous layers were found at the CoNx/Si interface, where the top layer has a Si-N bonding state and the bottom layer has a Co-Si intermixing state. The amorphous layer with the Si-N bonding state appears to suppress the diffusion of Co into the Si substrate, enabling the growth of the CoSi2 epitaxial layer. The new CoNx interlayer, which can be easily removed by chemical etching, can be easily adapted to existing ultralarge-scale integrated technologies. (c) 2006 The Electrochemical Society.