Surface segregation of Si in delta-doped In0.53Ga0.47As grown by molecular beam epitaxy

A study of Si spreading in delta-doped InGaAs grown lattice matched on InP by molecular beam epitaxy is reported. The layers were designed to distinguish between thermal diffusion and surface segregation as mechanisms for migration of the dopant atoms. Comparison of Shubnikov-de Haas data with self-consistent calculations shows that spreading occurs by surface segregation at substrate temperatures in the range 470-520 degrees C and Si densities of less than or equal to 4.0 x 10(12) cm(-2), thermal diffusion is found to be negligible. A near ideal delta-doping profile can be maintained if a delta-doped layer is capped with as little as 3 monolayers of InGaAs grown at less than or equal to 470 degrees C before subsequent material is deposited at higher temperatures, up to similar to 520 degrees C.