Interfacial reaction and adhesion between SiC and thin sputtered nickel films

Abstract

Thin sputtered nickel films grown on SiC were annealed in an Ar/4 vol % H2 atmosphere at temperatures between 550 to 1450 °C for various times. The reactivity and the reaction-product morphology were characterized using optical microscopy, surface profilometry, X-ray diffraction, scanning electron microscopy and electron probe microanalysis. The reaction with the formation of silicides and carbon was observed to first occur above 650 °C. Above 750 °C, as the reaction proceeded, the initially formed Ni3Si2 layer was converted to Ni2Si and carbon precipitates were observed within this zone. The thin nickel film reacted completely with SiC after annealing at 950 °C for 2 h. The thermodynamically stable Ni2Si is the only observed silicide in the reaction zone up to 1050 °C. Above 1250 °C, carbon precipitated preferentially on the outer surface of the reaction zone and crystallized as graphite. The relative adhesive strength of the reaction layers was qualitatively compared using the scratch test method. At temperatures between 850 to 1050 °C the relatively higher critical load values of 20–33 N for SiC/Ni couples are formed.