Dopant behaviour and damage annealing in silicon implanted with 1 kev arsenic

The level of activation in ultra-shallow As doped Si as a function of the anneal condition has been investigated with spreading resistance profiling (SRP), four point probe (FPP) and Van der Pauw (VDP) methods. Double alignment medium energy ion scattering (MEIS) and low energy secondary ion mass spectrometry (SIMS) have been used to assess the damage annealing and dopant behaviour in the near surface regions. An inactive dopant solid solution was formed in Si following re-growth of the amorphous layer. When annealing in an oxidising ambient, although a high fraction of the implanted dose remains trapped in the oxide layer, a higher level of electrical activation is observed than compared to the non-oxidising anneal. Evidence of dopant out diffusion is observed during high temperature annealing in a non-oxidising gas ambient. The processes that occur during the anneal in the near surface regions of the sample have been discussed and related to the level of dopant activation achieved.