A one step annealing for dopants activation, silicide resistivity lowering and glass flow by rapid thermal processing

A method to achieve titanium silicide resistivity lowering, dopants activation, and glass reflow in a one-step rapid thermal annealing (RTA) was developed with the objective of minimizing the thermal degradation of the silicide layer. It is found that the resistivity of TiSi/sub 2/ after high-temperature RTA essentially depends on whether or not the surface layer, which is formed during the first RTA in nitrogen ambient, was selectively removed before PSG deposition and reflow. With this protection film, a sheet resistance lower than 2 Omega /square. On the gate and diffusion areas was obtained. Without it, a considerable resistivity increase is observed. The barrier effect of this nitride layer is believed to be primarily responsible for this better stability. The efficiency of the method is demonstrated in a 1.5- mu m polycide process.<>