Vapor Deposition Of Silicon Films Research Articles

Electrical properties of highly boron-implanted polycrystalline silicon after rapid or conventional thermal annealing

Conductivity and Hall measurements were carried out on highly boron-implanted (5×1015 cm−2) low-pressure chemical vapor deposited silicon films. Polycrystalline films were annealed using a rapid thermal annealing (RTA 10 and 20 s) at 950, 1050, and 1150 °C, or standard furnace annealing [conventional thermal annealing (CTA) 950 °C, 30 min]. The Hall mobility and carrier density of the RTA films were higher than those of CTA films. Moreover, the temperature dependence of the mobility in RTA films showed a very striking behavior at high temperatures, i.e., the mobility decreased with increasing temperature, whereas CTA films showed thermally activated mobility. These results are analyzed in terms of the electrical activity of grain boundaries.

Structural and technological properties of heavily in situ phosphorus-doped low pressure chemically vapour deposited silicon films

Films of 100–200 nm thickness doped with 1021 P cm−3 were isothermally deposited at temperatures ranging from 520 to 620°C from an SiH4-PH3-H2 gas mixture. The structure (as deduced from transmission electron microscopy observations of sample plane views and cross-sections) and electronic properties (ultraviolet reflectance, resistivity, wet etching and oxidation rate) of the films showed specific features which are associated with nucleation and crystal growth mechanisms occurring at the gas-film interface during the deposition of the films.

Mechanical stresses in low pressure chemically vapour deposited silicon films

Stresses vs. deposition temperature and annealing time have been studied in silicon films 0.15 and 0.30 μm thick. The films were deposited onto oxidized silicon wafers by low pressure chemical vapour deposition from a gas mixture containing 5% SiH 4 and 95% Ar in a horizontal-type reactor at temperatures of 793–853 K. The films were annealed during 0.25–1.0 h flowing argon at 1223 K. Stresses have been found to increase from about 300 to about 500 MPa as the deposition temperature increases from 833 to 853 K. This is due to oxidation of film crystallites during deposition and a change in the condensation mechanism with temperature. The validity of a model allowing for crystallization of the amorphous phase during deposition has been confirmed by X-ray diffraction, reflection high energy electron diffraction and scanning electron microscopy. It is shown that a decrease in compressive stresses in the films containing a considerable fraction of amorphous phase is caused by crystallization and dynamic recrystallization of the films owing to annealing. A general equation has been derived which describes changes in the film elastic energy during crystallization taking into account plastic deformation. By using the deformation mechanism map it is shown that the stress reduction during annealing of polycrystalline films is caused by low temperature dislocation (power law) creep.

The Analysis of Plasma‐Enhanced Chemical Vapor Deposition of Silicon Films: A Comparison of Predictions with Measurements

A general mathematical representation has been developed for plasma‐assisted CVD systems. In this formulation, allowance is made for fluid flow, slip at the interface, and for both the thermal and plasma‐assisted decomposition of the reactant gas. The use of the model is illustrated with a specific example: the decomposition of silane to give a silicon film. The theoretical predictions were found to be in reasonable agreement with the measurements.

Chemical Vapor Deposition of Silicon Films by Pulsed CO2 Laser Irradiaton of Silane

ABSTRACTSilane molecules have been irradiated by a pulsed CO2 laser operating at 10.59 μm. The threshold of silicon formation by homogeneous dissociation of silane has been investigated as a function of laser fluence (0.1–3.5 J/cm2) and silane pressure (1–100 Torr). Silicon films have been deposited on quartz substrates using the laser beam either perpendicular or parallel to the substrate surface. The crystallographic structure and deposition rate of these silicon films are found to be dependent on the incident angle of the laser beam, silane pressure, substrate temperature and laser fluence. The growth mechanism of these films is discussed.

Chemical vapour deposition of silicon films in capillary layers

A simple experimental method for the direct derivation in chemical vapour deposition (CVD) of the decomposition probability of a reactant molecule per surface collision is described. The method is based on the analysis of the thickness profile of a thin film deposited onto the internal walls of a two-dimensional capillary cavity. It is shown that for a unimolecular decomposition reaction the thickness profile decays exponentially with the depth in the cavity. From the decay constant and from the time it takes to reach a given thickness profile, both the decomposition probability and the diffusion coefficient of the reactant molecules are obtained. The method is demonstrated for the CVD of silicon from silane diluted in helium at atmospheric pressure. At 600°C a decomposition probability of 2×10 -6 is obtained.

Chemical vapour deposition of silicon films in capillary layers

Chemical vapour deposition of silicon films in capillary layers