Optical properties and structure of amorphous silicon films prepared by CVD

Nucleation and growth of silicon by CVD

The subatmospheric pressure chemical vapour deposition (CVD) process has been used to fabricate theoretically dense, highly pure, void free and large area infrared-optical and ceramic materials such as ZnS, ZnSe, CdS, CdZnTe, Si and SiC. In this paper, an overview of a large scale CVD process is presented emphasizing the important technical and engineering issues such as control of material properties, injector heating and its effect on growth, selection of an appropriate mandrel material, grain growth, material bowing, nodular growth, and storage, transport and scrubbing of a large quantity of hazardous chemicals. Further, the flow pattern in our CVD reactors is described and its importance in achieving good control over thickness and composition uniformity over large areas is discussed.

Monolithic material fabrication by chemical vapour deposition

The kinetics of the deposition of silicon by silane pyrolysis at low temperatures and atmospheric pressure

Low-temperature (400–540 °C) crystallization of amorphous and polycrystalline Si films deposited on SiO2 and covered with an evaporated Al layer has been studied using SEM, TEM, electron diffraction, electron channeling, and MeV 4He + backscattering. Silicon deposited by evaporation and chemical vapor deposition (CVD) at 640 °C (both amorphous) was found to crystallize into islands of polycrystalline aggregates. Silicon deposited by CVD at 900 °C (polycrystalline with ~2000-A grains) produced relatively large (~10 µm) single-crystal islands. In both cases island size increased with annealing time, and the rate of crystallization increased with temperature. Crystallization rates were observed to be the same for both sources of amorphous Si, while 900 °C CVD Si was noticeably slower, consistent with the postulate that the driving force for the reaction is the free-energy difference between initial and final states. The crystallization rate for 900 °C CVD Si decreased when the Al layer thickness was reduced to a value less than the initial Si grain size. The inclusion of a native oxide layer between the deposited Si and Al layers greatly retarded the crystallization process.

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Solid‐phase crystallization of Si films in contact with Al layers

Durch Transmissionselektronenmikroskopie werden die Strukturen polykristalliner Si-Filme (die aus der Dampfphase aus Silan erhalten wurden) auf Si3N4- und SiO2-Substraten untersucht.

A. Emmanuel

Papers

Growth of Polycrystalline Silicon Films: Grain Size

Growth of polycrystalline silicon films, grain size