Differential thermal budget in laser processing: application to formation of titanium silicide

One of the crucial issues that must be faced when using titanium silicide in advanced IC structures is the difficulty encountered in phase transforming the silicide from the its high to its low resistivity phase. As gate dimensions are reduced there is a reduction in the number of nucleation sites available to initiate transformation on laterally and vertically confined films. In this letter, we demonstrate a novel technique, using a pulsed excimer laser, to produce thicker silicides over the gate than over the source and drain regions. This is difficult to achieve using conventional thermal processing. The increased thickness of silicide over the gate region should assist in alleviating the phase transformation problem.