Interpretation of interfacial structure for ultra thin Ni film on SiC using synchrotron radiation photoemission spectroscopy

The changes in atomic bonding state at the interface of ultra thin Ni film (25 A) with SiC were investigated as a function of annealing temperature using synchrotron radiation photoemission spectroscopy (SRPES). From these, the early stage in the reaction to form Ni silicide was examined. It was found that Ni2Si began to form below 600 degree C. However, at 300 degree C Ni atoms migrated on the surface of SiC, leading to the formation of Ni islands and the substrate is partially exposed, prior to the formation of Ni silicide. When Ni2Si was formed, the binding energy of SiC bond was not changed, but work function of the contact layer was increased. This provides the evidence that Schottky barrier height was increased with increased with the formation of Ni silicide via the increase in work function of contact layer