CRYSTAL-GROWTH AND ELECTRONIC-PROPERTIES OF ULTRAHIGH-VACUUM ION-BEAM SPUTTER-DEPOSITED SB-DOPED SI(001)2X1

High-quality homoepitaxial Sb-doped Si(001)2x1 films have been grown on p-type Si(001) substrates by ultrahigh vacuum ion-beam sputter deposition (IBSD) at temperatures T(s) between 450 and 750-degrees-C. The load-locked multichamber system is equipped with in situ reflection high-energy electron diffraction. Sputter deposition was carried out using a 1 keV Kr+ ion beam generated by a modified Kaufman-type ion source with post-extraction electrostatic ion optics. All films were 1 mum thick and deposited at a rate of 0.35 mum h-1. Results of plan-view, cross-sectional, and convergent-beam transmission electron microscopy analyses showed that as-deposited films are highly perfect with no visible defects. Sb incorporation probabilities sigma(Sb) ranged from -0.1 at T(s) = 750-degrees-C to congruent-to 1 for T(s) less-than-or-equal-to 550-degrees-C with no indication by secondary-ion mass spectrometry (SIMS) of Sb surface segregation. These sigma(Sb) values are one to three orders of magnitude larger than for coevaporative Sb doping during molecular beam epitaxy where extensive Sb surface segregation is observed. A comparison of calibrated SIMS and Hall-effect measurements established that the incorporated Sb exhibited complete electrical activity. SIMS analyses also showed no detectable Kr (detection limit congruent-to 5 x 10(17) cm-3). Temperature-dependent (15-300 K) electron mobilities were equal to the best reported bulk Si values.