Amorphous silicon

About: Amorphous silicon is a research topic. Over the lifetime, 26777 publications have been published within this topic receiving 423234 citations.

Method of forming polycrystalline silicon film in process of manufacturing LCD

Abstract: In a method of forming a polycrystalline silicon film in a process of manufacturing an LCD, a hydrogenated amorphous silicon film is formed on a glass substrate by plasam CVD throughout areas serving as the pixel portion and driver unit of the LCD. A laser beam is radiated on a selected region of the film on the area serving as the driver unit. The energy of the laser beam is set such that hydrogen in the film is discharged without crystallizing the film and damaging the film. The energy of the laser beam is gradually increased to gradually discharge hydrogen from the film. The energy of the laser beam is finally set such that the film is transformed into a polycrystalline silicon film. The amorphous silicon film can be poly-crystallized without damaging the film by the discharge of hydrogen.

Excess specific heat in evaporated amorphous silicon.

Abstract: The specific heat C of e-beam evaporated amorphous silicon (a-Si) thin films prepared at various growth temperatures T(S) and thicknesses t was measured from 2 to 300 K, along with sound velocity v, shear modulus G, density n(Si), and Raman spectra. Increasing T(S) results in a more ordered amorphous network with increases in n(Si), v, G, and a decrease in bond angle disorder. Below 20 K, an excess C is seen in films with less than full density where it is typical of an amorphous solid, with both a linear term characteristic of two-level systems (TLS) and an additional (non-Debye) T3 contribution. The excess C is found to be independent of the elastic properties but to depend strongly on density. The density dependence suggests that low energy glassy excitations can form in a-Si but only in microvoids or low density regions and are not intrinsic to the amorphous silicon network. A correlation is found between the density of TLS n0 and the excess T3 specific heat c(ex) suggesting that they have a common origin.

Electron mobility in amorphous silicon thin-film transistors under compressive strain

Abstract: We evaluated amorphous silicon thin-film transistors under uniaxial compressive strain of up to 1%. The on-current and hence the electron linear mobility decrease. The off-current, leakage current, and the threshold voltage do not change. The mobility decreases linearly with applied compressive strain. Upon the application of stress for up to 40 h the mobility drops “instantly” and then remains unchanged. We conclude that compressive strain broadens both the valence and conduction band tails of the a-Si:H channel material, and thus reduces the effective electron mobility.

Electronic transport in doped amorphous silicon.

Abstract: The temperature dependence of the dc dark conductivity of doped hydrogenated amorphous silicon is explained by the defect-compensation model of doping with the proposal that the structure is in metastable thermal equilibrium. Observed conductivity activation energies and preexponential factors can be accounted for quantitatively. When the localized state distribution is in thermal equilibrium, the conductivity preexponential factor is the Mott minimum metallic conductivity.