Abstract:

Smooth, continuous, relaxed, and high quality Ge ®lms have been grown on Si(111) using surfactant-mediated epitaxy (SME). Using high temperature SME we have reduced the Sb surfactant doping level by more than three orders of magnitude below the solid solubility. This enhanced surfactant segregation is attributed to the formation of an ordered (2 £ 1)-Sb reconstruction on the Ge(111) growthfront. With increasing growth temperature the Sb incorporation decreases to 1 £ 1016cm23 at 7008C. This low Sb doping concentration has been determined by electrical characterization. The electron Hall mobility varies strongly with the doping concentration. Record values of 3159 cm2/Vs at 300 K suggest interesting potential of SME grown Ge ®lms for future device applications. Capacitance voltage measurements on vertical p1n diodes show a uniform doping pro®le and are in good agreement with Hall measurements. q1998 Elsevier Science S.A. All rights reserved