IMPROVEMENT OF THERMALLY FORMED NICKEL SILICIDE BY ION IRRADIATION.

Abstract

A significant improvement of the lateral uniformity of thermally formed Ni//2Si layers has been observed after low-dose (10**1**3 to about 3 multiplied by 10**1**4 ion/cm**2) Xe irradiation of an As-deposited Ni film. Measurements have also been made on samples that contained a thin impurity layer formed intentionally between the silicon substrate and the evaporated nickel film. The impurity layer was thick enough to prevent thermal silicide formation in unirradiated samples, but in irradiated samples, the silicide formation was not prevented. Similar results were obtained for As implantations. This effect is attributed to ion mixing of the interfacial layer. These results demonstrate that a low-dose irradiation can render the process of silicide formation by thermal annealing more tolerant to interfacial impurities. The concept is of potential significance to VLSI technology.