Abstract. N type as well P type top gate microcrystalline silicon thin film transistors (TFTs) are fabricated on glass substrates at a maximum temperature of 200°C. The active layer is an undoped µc-Si film, 200 nm thick, deposited by Hot-Wire Chemical Vapor. The drain and source regions are highly phosphorus (N-type TFTs) or boron (P-type TFTs) doped µc-films deposited by HW-CVD. The gate insulator is a silicon dioxide film deposited by RF sputtering. Al-SiO 2 -N type c-Si structures using this insulator present low flat-band voltage, -0.2V, and low density of states at the interface D it =6,4 x 10 10 eV -1 cm -2 . High field effect mobility, 25 cm 2 /V.s for electrons and 1.1 cm 2 /V.s for holes, is obtained. These values are very high particularly the hole mobility that it was never reached previously. .

Strain-induced metal-insulator (MI) transitions have been observed in degenerately doped Si:Sb and Ge:Sb crystals at T = 4.2 K and for extremely high uniaxial pressures up to 5 GPa. It is shown that in both Si and Ge the transition from a metallic-type to an activated conductivity is determined by strain-induced changes of the conduction band parameters. The data obtained demonstrate that the effective mass donor approach and the scaling theory of localization describe well the MI transition phenomenona observed.

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The analysis of experimental data on the pressure and temperature dependences of conductivity, the current-voltage characteristics (IVC), and the pressure dependence of the activation energy in n-Si and n-Ge crystals in the region of strain-induced metal-insulator transition (MIT) is presented. A remarkable change of the effective mass of carriers in semiconductors caused by straininduced transformation of the energy band structure is the main necessary condition for realization of this kind of metal-nonmetal transition.