Passivation of dopants in ion implanted and rapid thermally annealed GaAs in H⁺ plasma environment

Abstract

It is demonstrated using RTA that the electrical activation of Si+ implanted GaAs capped with a PECVD silicon nitride (SiNx) layer requires longer annealing times compared to capless annealing. Furthermore, anomalous carrier passivation occurs during capped annealing of the Si implanted samples containing a buried-p layer. It was found using deuterated SiNx caps that 2D diffuses from the cap into the implanted region during subsequent annealing. The improvement in the electrical activation with annealing time correlated with the decreasing concentration of the 2D in the implanted region of the GaAs. It is postulated that the H atoms diffusing into GaAs during PECVD interact with implanted dopants and concomitant damage and retards the electrical activation of the dopants. The anomalous electrical effects observed in samples with a buried-p layer are also associated with the H diffusion.