Surface gettering of background impurities and defects in GaAs wafers

The first data on surface gettering of background impurities and defects fr om the bulk of single-crystal undoped GaAs(111) wafers are reported. The wa fers were 1.6 mm thick, with an initial electron density of (1-3) x 10(15) cm(-3) and a mobility of 1500-2000 cm(2)/(V s) at room temperature. The waf ers were cut from single crystals grown by the Czochralski method from a no nstoichiometric As-enriched Ga-As melt. Gettering was carried out during th ermal treatment of the wafers in hydrogen at 400-850 degreesC, with the pre liminary deposited layer of Y or SiO2 1000 Angstrom thick. As a result of g ettering, the charge carrier density decreased to 10(8)-10(10) cm(-3), whil e the mobility increased to 7000 cm(2)/(V s). (C) 2001 MAIK "Nauka/Interper iodica".