Получение тонких пленок графита на диэлектрической подложке с помощью гетероэпитаксиального синтеза

The results of testing the methods of preparation of thin graphite films on a dielectric substrate by the method of annealing the structure of (0001) Al2O3/(111) Ni/ta-C are present. The method is based on catalytic decomposition of hydrocarbons on the surface of the monocrystalline film of the metal-catalyst on the surface of the dielectric substrate and subsequent diffusion and crystallization of carbon between the metal film and the substrate. After chemical etching of the metal film, a thin graphite film with low density of crystal structure defects on a dielectric substrate is obtained.

WHY CAN SMART CUT® CHANGE THE FUTURE OF MICROELECTRONICS?

Deposition techniques like chemical vapor deposition (CVD) offer to the semiconductor industry the initial flexibility to deposit thin films of key materials on many kinds of substrates. The homoepitaxy or hetroepitaxy techniques using CVD or molecular beam epitaxy (MBE) add the flexibility to get a pure monocrystalline thin film but with a major limitation: the starting substrate has to be monocrystalline. The missing technology has always been the one which allows the growth of a thin monocrystalline film on any kind of substrate. Hydrogen induced splitting (known today as Smart Cut®), discovered at the LETI laboratory in 1991, provides a unique opportunity to get crystalline layers on any kind of substrate. Therefore, a new tool is offered to the semiconductor industry, for new material developments and new structures. This technique is in use in production today on a first application: silicon-on-insulator (SOI) wafers which consist of a monocrystalline film of silicon on a thin amorphous silicon dioxide layer, on top of a silicon wafer. We will discuss the SOI application of the Smart Cut® technology and present other recently demonstrated breakthroughs in new material development, including SiC, compound semiconductor or 3D structures.

Preparation of Thin Films of some Rem Oxides and study of Their Structure, Optical, and electrical properties

ABSTRACTBy ion bombardment of yttrium and europium hot-pressed oxide targets, their amorphous polycrystalline and monocrystalline films have been obtained on the monocrystalline substrates of (111) molybdenum and (1012). (0001) sapphire. The growth direction of the monocrystalline films with respect to the material and orientation of the substrates corresponds to (011). (211) planes for Y2O3 and (011) Eu2O3.It is determined that the structural imperfection of the grown films does not influence either the square root dependence of the absorption coefficient on decreasing photon energy, the value of their specific electric resistance, or the character of its temperature dependence. The values of the forbidden zone width as well as the energy of the investigated oxide conductivity activation are calculated on the basis of experimental results.It is shown that the light absorption in the Y2O3, Eu2O3 films is mediated by the direct allowed transitions of electrons from the valence band to the conduction band whose extrema are at the same point in k-space. The conductivity of the metal-dielectric-metal structure based on a monocrystalline film of yttrium oxide is mediated by the Frenkel-Poole mechanism.

Size and Grain-Boundary Effects in the Electrical Conductivity of Thin Monocrystalline Films

By assuming that the scattering processes from other sources than grain-boundaries can be described by a single relaxation timeτ∗and then by solving a Boltzmann equation in which grain-boundary scattering is accounted for, we have obtained an analytical expression for the thin monocrystalline film conductivity in terms of the reduced thicknesskand the grain-boundary reflection coefficientr. Numerical tables are given to show the agreement of the above expression with the Mayadas-Shatzkes expression.