It is found that epitaxial CeO2 layers with (100) or (110) orientation can be selectively grown on Si(100) substrates by controlling substrate bias in reactive dc magnetron sputtering. Adopting a two step growth method; ultrathin metallic Ce layer deposition at room temperature followed by a silicidation process at 800 °C, and subsequent reactive sputtering in an Ar/O2 mixture environment, the CeO2(100) layer is grown on practical Si(100) surfaces prepared by the usual wet cleaning method.

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We have systematically studied the electrical properties of heavily Si-doped GaAs grown on the (311)A GaAs surfaces by molecular beam epitaxy. It is found that the conduction type drastically changes from p type to n type with decreasing growth temperature at a critical temperature of ∼430 °C for uniform doping and ∼480 °C for the δ-doping case, with the transition temperature width as narrow as ∼50 °C for both cases. The highest hole density obtained for uniformly doped layers was 1.5×1020 cm−3, while for δ-doped layers a sheet hole density as high as 2.6×1013 cm−2 was achieved, which is the highest sheet hole density ever reported for δ-doped p-type GaAs.

PACS 73.61. Jc, 78.30.Ly, 78.66.Jg, 81.05.Gc B, P or Sb were doped into amorphous silicon films by the reactive radio-frequency co-sputtering method. The targets used were composed of silicon wafers and small about 1 mm thick chips of the respective impurity element, which were attached to the silicon wafers with silver powder cement and epoxy resins. Argon and hydrogen partial pressures used were 5 × 10 −3 and 5 × 10 −4 torr, respectively. The impurity concentration in the film was determined by secondary ion mass spectroscopy for B and P and by He backscattering spectroscopy for Sb. The substrates were kept at 200 -250 °C during deposition. Raman spectra revealed that films prepared even at 250 °C were amorphous. Heterostructures, where P-, Sb-or B-doped films were deposited on p-or n-type Si, exhibited good rectification characteristics of p -n diodes. It has been shown that the co-sputtering method can produce low-resistivity p-type (B) and n-type (P) a-Si : H films for relatively low concentrations of B and P, respectively.

We have systematically studied the dependence of the electrical properties of Si-doped (311)A GaAs on the growth conditions in molecular beam epitaxy and have established a phase diagram for the conduction type as functions of the growth temperature and the V4/III flux ratio. A sharp boundary is observed for the transition between the p- and n-type conduction, on both sides of which the activation efficiency of Si is close to unity. Furthermore, it is found that, in contrast to the case of the (111)A GaAs, the conduction-type conversion in Si-doped (311)A GaAs does not show a clear correlation with the macroscopic surface morphology, suggesting that the mechanism for the conduction-type conversion in Si-doped (311)A GaAs is different from that for the (111)A orientation.