Effects of oxygen-inserted layers and oxide capping layer on dopant activation for the formation of ultrashallow p-n junctions in silicon

The effects of oxygen-inserted (OI) layers and a low-temperature-deposited oxide (LTO) capping layer on rapid thermal activation of ultrashallow implanted boron, phosphorus, and arsenic atoms in silicon (Si) are investigated using sheet resistance ( R sh ) measurements, secondary ion mass spectrometry analyses, and technology computer-aided design simulations. The experimental findings suggest that the electrical activation of dopants in Si is not significantly affected by the presence of OI layers so that they can be effective for achieving lower R sh along with shallower junction depth, thanks to reduced dopant loss and diffusion during thermal annealing. On the other hand, an LTO capping layer is found to result in larger R sh associated with the lower peak active dopant concentration as a result of dopant segregation and/or reduced uphill diffusion. The presence of OI layers is found to mitigate these detrimental effects.