Electrical properties of Si(100) films doped with low-energy (≤150 eV) Sb ions during growth by molecular beam epitaxy

A low-energy ultrahigh-vacuum compatible ion gun with single-grid optics was used to provide accelerated Sb ion doping during the growth of Si(100) by molecular beam epitaxy (MBE). The incorporation probability of accelerated Sb in MBE Si films grown at 800 °C with an ion acceleration potential of 150 eV was near unity, more than four orders of magnitude higher than for thermal Sb. The films exhibited complete dopant substitutionality and temperature-dependent electron mobilities were equal to the best reported bulk Si values for Sb concentrations up to 2×10¹⁹ cm^-3, more than an order of magnitude higher than obtainable by thermal Sb doping during Si MBE. Transmission electron microscopy examination of all films showed no evidence of dislocations or other extended defects.