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The dielectric and structural properties of LaAlO3 make it an attractive epitaxial gate oxide for nanometer-scale field effect transistors. However, the growth of epitaxial LaAlO3 directly on Si has not been possible to date. In order to achieve LaAlO3 epitaxy, we use a SrTiO3 template layer whose thickness minimizes elastic strain and atomic-level buckling at the interface. We find that LaAlO3 grown on this template layer is crystalline and initially strained, but relaxes to its bulk lattice constant within 7 unit cells. Cross-sectional transmission electron microscopy and inelastic electron tunneling spectroscopy studies of the LaAlO3/SrTiO3/Si structure show no evidence of an amorphous SiO2 layer. Capacitance-voltage measurements on thin films of epitaxial LaAlO3/SrTiO3/Si with LaAlO3 thicknesses between 13 and 110 nm show a dielectric constant for the LaAlO3 layer of 24, the same value as for the bulk. After a post-deposition low temperature anneal, these oxide heterostructures show no Fermi level pinning and an interface state density of ∼8×1010 cm−2 eV−1.

We describe the fabrication and operation of a polysilicon room-temperature memory device. The source-drain current-voltage (I -V ) characteristics of this device, with floating gate, demonstrate periodic current steps as well as hysteresis generic for a memory device. Electron micrographs show that the channel consists of 3-5 nm silicon grains. A model of single charge trapping controlled conduction through the device channel is suggested.

A study of epitaxial growth of YBa2Cu3O7−δ films on oxidized Si with yttria- and zirconia-based buffer layers is reported. Using substrates with either SiO2 free or naturally oxidized (100) surfaces of Si it was found that a thin SiO2 layer on top of the Si favors high-quality superconducting film formation. Compared to yttria-stabilized ZrO2 (YSZ) single layers, YSZ\Y2O3 double and YSZ/Y2O3\YSZ triple layers allows the deposition of thin YBa2Cu3O7−δ films with improved properties including reduced aging effects. In epitaxial YBa2Cu3O7−δ films grown on the double buffer layers a critical temperature Tc(R=0)=89.5 K and critical current densities of 3.5×106 A/cm2 at 77 K and 1×107 A/cm2 at 66 K were reached.

The effect of substrate temperature on the growth rate, crystal grain size, and SiO 2 mask stability in the selective epitaxial growth of silicon carbide deposited from SiH 4 , C 2 H 4 , and HCl 1 on silicon dioxide masked silicon ͑100͒ was examined. Depositing at atmospheric pressure and a Cl/Si input ratio of 50 to achieve good selectivity, increasing the substrate temperature from 950 to 1000°C increased the growth rate and the crystal size, and improved the film's surface morphology, but also enhanced the SiO 2 mask degradation rate, causing a loss of selectivity for long deposition times. For prolonged deposition times at 1000°C, SiC nucleation occurred at both voids formed in the mask from its reaction with the silicon substrate and on the SiO 2 mask itself-a consequence of increasing oxide surface roughness. ͓S0021-8979͑98͒00213-8͔