ELECTRICAL-PROPERTIES OF BURIED B SI SURFACE PHASES/

Conductivity and Hall-effect measurements have been carried out at 24 K for a set of various layered structures with buried B/Si surface pha ses used as delta-doped layers. Evidence is found for hole mobility en hancement as a consequence of boron dopant ordering. The electrical me asurements reveal a basic difference in room temperature adsorption fo r boron on Si(100) and Si(111) surfaces. The characterization of the s amples containing buried B/Si(111) interfaces and extra-thin Ge layers suggests promise for improving the structure and electrical propertie s of the buried surface phases. The hole mobility in epi-Si/Ge/B/Si(11 1) structures is found to be about 2.5 times higher than in epi-Si/B/S i(111) samples. (C) 1998 American Institute of Physics. [S0021-8979(98 )04310-2].