Method for selective deposition of refractory metal and device formed thereby

摘要

A method and the device produced by the method of selective refractory metal growth/deposition on exposed silicon, but not on the field oxide is disclosed. The method includes preconditioning a wafer in a DHF dip followed by the steps of 1) selectively depositing a refractory metal on the exposed surfaces of the silicon substrate by reacting a refractory metal halide with the exposed surfaces of said silicon substrate; 2) limiting silicon substrate consumption by reacting the refractory metal halide with a silicon containing gas; and 3) further increasing the refractory metal thickness by reacting the refractory metal halide with hydrogen. Through an adequate pretreatment and selection of the parameters of 1) temperature; 2) pressure; 3) time; 4) flow and 5) flow ratio during each of the deposition steps, this invention adequately addresses the difficulties of uneven n+ versus p+ (source/drain) growth, deep consumption/encroachment by the refractory metal into silicon regions (e.g., worm holes), poor adhesion, uncontrolled selectivity and uneven morphology.