Atomic layer deposited solid sources for doping of high aspect ratio semiconductor structures

Plasma-assisted atomic layer deposition (PALD) was carried out for growing thin oxide films containing dopants for silicon, germanium, and SiGe onto flat and high-aspect ratio substrates. The applicability of these films as dopant sources for shallow doping using different rapid thermal annealing (RTP) methods, such as conventional RTP and flash lamp anneal (FLA), was investigated. Remote CCP and ICP sources were applied for generating oxygen radicals in the PALD processes. Oxides containing boron, phosphorus or antimony were grown and investigated for the doping experiments. Conformal growth of such films could be obtained on silicon trench structures up to ~15:1 aspect ratio with pitch below 50 nm. Shallow boron and phosphorus doping of silicon could be obtained using the respective oxide films as dopant sources. Controlled doping of 3-D nanostructured devices by pre-deposition with ALD source layers should be feasible by this method.