CARRIER PASSIVATION IN HEAVILY-DOPED GAAS-BE BY HYDROGEN PLASMA

The electrical property around the surface of a heavily Be-doped p(+) GaAs layer exposed to hydrogen plasma has been investigated. The resis tance around the surface has been made over six orders of magnitude la rger by a 150 W and 10 min plasma exposure. Sheet carrier measurement with step etching has shown that the depth of the passivated front pro ceeds by diffusion. The time dependence of carrier removal has been fo und to have three distinct regions including a plateau. These regions have been explained by a 50 nm thick highly resistive layer which is f ormed within the first 1 minute during the plasma treatment prior to p assivation due to hydrogen diffusion.