A NOVEL TECHNIQUE FOR ULTRATHIN COSI2 LAYERS - OXIDE-MEDIATED EPITAXY

A novel technique, oxide mediated epitaxy (OME), was recently describe d for the growth of single crystal CoSi2 layers on the (100), (110); a nd (111) surfaces of silicon. Deposition of a thin layer of cobalt (1- 3 nm) onto Si surfaces covered with a thin peroxide-grown SiOx layer a nd annealing at 500-700 degrees C led to the growth of essentially uni form, epitaxial CoSix layers. The thin SiOx layer remained largely on the surface of the OME grown CoSi2 layers as a cap. Deposition of coba lt at elevated temperature onto OME grown CoSi2 layers led to a signif icant re-evaporation of cobalt from the SiOx surface. Presently, the O ME effect was demonstrated on heavily doped p(+) and n(+)-Si and on na rrow (0.22 mu m) Si lines. On all surfaces, thin (10-30nm), excellent quality CoSi2 single crystal thin films were grown by repeated growth sequences involving depositions of cobalt at room temperature and anne als at 600-700 degrees C. It was also shown that faceting at CoSi2/Si( 100) interfaces could be significantly reduced by a high temperature a nneal.