Controlling surface shallow junction depth by a rapid thermal annealing process with low ambient pressure

We demonstrate the effect of annealing pressure on the redistribution of phosphorus dopants in silicon. The phosphorus concentration in the kink region is dependent on the annealing pressure that enhances the phosphorous transient out-diffusion. The phosphorous in-diffusion in the tail region is suppressed by this transient out-diffusion under low annealing pressure (below the atmosphere), and the surface shallow junction depth is reduced. The phenomenon of dose loss caused by the phosphorous piling-up or sublimation at the surface has an influence on the electrical characteristics and the surface roughness. Moderate annealing pressure can reduce the junction depth and only slightly increase the sheet resistance and surface roughness.