Bulk acceptor compensation produced in p-type silicon at near-ambient temperatures by a H2O plasma

Abstract

We report the neutralization of the shallow acceptors boron and gallium in p‐type silicon to a depth >1 μm after exposure to a H₂O plasma for 3 h at temperatures as low as 80 °C. The fact that uncompensated n‐type silicon is unaffected by the plasma treatment means that donor formation is excluded. Exposure to either O₂ or H₂ plasmas does not lead to acceptor removal; however, sequential treatment in an O₂ plasma followed by a H₂ plasma produces the same effect as the H₂O plasma while the inverse sequence has no effect. Our observations can be explained with a model considering rapidly diffusing atomic oxygen and hydrogen which recombine on acceptor sites forming neutral A⁻OH⁺ complexes. The model shows that acceptor compensation kinetics is dominated by the diffusion of atomic hydrogen.