Boron segregation in As-implanted Si caused by electric field and transient enhanced diffusion

Boron segregation in an implanted arsenic profile in Si during annealing was investigated under various annealing conditions. It was found that both the implant damage created by arsenic implantation and arsenic deactivation enhance the diffusion of the embedded boron layer toward the shallow As implanted profile. The segregation phenomenon was observed in both 650 °C furnace annealed (FA) and 1000 °C rapid thermally annealed (RTA) samples. For the 650 °C FA sample, the boron segregation peak was located at the junction formed by implanted As, where residual dislocation loops at the original amorphous/crystalline (a/c) interface were also observed. However, no a/c interface dislocation loops were found to be present for the RTA samples. Additional anomalous boron segregation was observed for the 1000 °C RTA+750 °C FA samples. The additional boron segregation is not correlated with defect layers. It is, therefore, concluded that the anomalous boron segregation is caused by the electric field resulting from the formation of a p-n junction.