Journal of Materials Research


An investigation of hardness and adhesion of sputter-deposited aluminum on silicon by utilizing a continuous indentation test

D. Stonea1, W. R. LaFontainea1, P. Alexopoulosa2, T. -W. Wua2 and Che-Yu Lia3

a1 Cornell University, Ithaca, New York 14853

a2 IBM Almaden Research Center, San Jose, California 95192

a3 Cornell University, Ithaca, New York 14853


The hardness of aluminum films on silicon are measured as functions of depth of the indenter. The films have thicknesses of 0.25,0.5, and 1.0μm. The adhesion between one film and the substrate has been reduced through the prior deposition of a 10 nm layer of carbon. In each case the hardness is found to increase as the indenter approaches the film-substrate interface, but the rate of increase is greater for a film with good adhesion than for one with poor adhesion. It is suggested that this increase results from the constraint on deformation of the film by the substrate. A physical model is proposed whereby the yield stress of the film, σo, and an average effective shear strength τ of the indenter-film and film-substrate interfaces, may be determined from the data.

(Received March 27 1987)

(Accepted September 21 1987)