Periodic Variation of Stress in Sputter Deposited Si/WSi2 Multilayers

摘要

A tension increment after sputter deposition of 1 nm of WSi2 onto sputteredSi was observed at low Ar gas pressures. Wafer curvature data on multilayerswere found to have a periodic variation corresponding to the multilayer period,and this permitted statistical analyses to improve the sensitivity to smallstresses. The observation of tension instead of compression in the initialstage of growth is new and a model invoking surface rearrangement is invoked.The data also bear on an unusual surface smoothing phenomena for sputtered Sisurfaces caused by the sputter deposition of WSi2 . We furthermore report thatfor low Ar pressures the Si layers are the predominant source of built-upstress.