A novel p-type implantation using a co-implant of phosphorus and beryllium to produce a shallow p+ surface layer is reported. The results from electrical measurement show an excellent control of the carrier profile. There is no Be in-diffusion observed and an improvement of the electrical activation also resulted.

Be is implanted into an n-InGaAs epitaxial layer. Both electrical and atomic profiles indicate that Be in-diffusion occurs during annealing, resulting in a p layer thicker than that desired. A co-implant of P or As with Be significantly reduces this Be in-diffusion resulting in shallow (2000 Å) p+-n junctions with 4×1018 cm−3 surface hole concentration and 70% electrical efficiency.