Fermi-Level-Pinning Induced Surface Segregation of Dopants in Delta-Doped Semiconductors
17 July 1989
In delta-doped Al sib x Ga sub (1-x) As:Si strongly localized dopant distributions with diffusion lengths = 11angstroms can be achieved at low substrate temperatures of 500C during growth by molecular-beam epitaxy (MBE). However, at higher growth temperatures asymmetric dopant profiles are observed which exhibit an enhanced motion to the surface. The segregation length increases up to 420angstroms at a substrate temperature of 660C as inferred from Secondary Ion Mass Spectroscopy (SIMS).