Novel Si surface cleaning technology with plasma hydrogenation and its application to selective CVD-W clad layer formation

We propose a new method to clean heavily-doped p/sup +/-Si surfaces by plasma hydrogenation prior to selective W CVD by using SiH/sub 4/ reduction. This cleaning technology reveals excellent characteristics: the improvement of W adhesion to p/sup +/-Si, low contact resistance, suppression of selectivity loss, and good controllability of Si consumption for p/sup +/- and n/sup +/-Si. Owing to this cleaning technology, we can obtain sufficiently low contact resistivities of 0.3 and 0.1 /spl mu//spl Omega/cm/sup 2/ for p/sup +/and n/sup +/ contacts for 1-/spl mu/m/sup 2/-W-cladding area, respectively. With the plasma hydrogenation cleaning and selective W CVD of SiH/sub 4/ reduction, Si consumption is suppressed to a low value below 14 nm for both types of silicon at 300/spl deg/C.