THERMAL-STABILITY OF SI COSI2 MULTIPLE LAYER SYSTEMS/

Multiple layer systems consisting of two silicon layers and two CoSi2 layers on Si [111] were formed by ion implantation and subsequent anne aling. The parameters of the layer systems (layer thicknesses. crystal line orientation etc.) were varied by the implantation and annealing c onditions. High temperature thermal annealing of the layer systems pro ved that the thin silicide layers are less stable than thicker ones. T hese layers dissolve and the deeper lying layers grow by consuming the Co released from the thin layers. The Co redistribution is a reaction controlled process and appears to be independent of the crystalline o rientation of the silicide. Noncontinuous silicide layers are less sta ble than continuous ones. The activation energy for the dissolution of a noncontinuous layer was determined to be (1.4 +/- 0.3) eV.