New Technique for Forming Continuous, Smooth, and Uniform Ultrathin (3 nm) PtSi Layers

An interfacial intermixed layer formed during sputtering at room temperature, and a subsequent selective etch step are found to be the keys for formation of continuous and uniform ultrathin layers. The etching, performed after the metal deposition, removes at very fast rates. The etch rate is slowed when the interfacial layer is reached and an oxide is formed on top of the intermixed layer, which prevents further etching. During this process, a short‐range diffusion mechanism is believed to transform the intermixed layer into a thick continuous film. A subsequent annealing results in a more uniform grain size distributing without changing the other characteristics of the film. Moreover, the silicide formed is insensitive to sputter conditions such as sputter power and time.