Synthesis of Powders and Thin Films by Laser Induced Gas Phase Reactions

ABSTRACTA novel method for preparing photoconductive Si thin films termed “Spontaneous Chemical Deposition”, is proposed, in which silane is decomposed spontaneously by gas phase reactions with fluorine at reduced pressure. With the external parameters in the gas phase reaction such as a gas flow ratio of SiH4 to F2 and the reaction pressure and temperature, the Si-network structure of the films can be controlled intentionally, resulting in a reduction of the hydrogen content, CH and a variety of the films from “amorphous” to “microcrystalline”.

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Deposition of Si Thin Films by Reactive CVD

MRS Proceedings ◽

10.1557/proc-377-105 ◽

1995 ◽

Vol 377 ◽

Cited By ~ 11

Author(s):

Jun-Ichi Hanna

Keyword(s):

Thin Films ◽

Low Temperature ◽

Gas Phase ◽

Film Growth ◽

Chemical Deposition ◽

Gas Phase Reactions ◽

Temperature Growth ◽

Low Temperature Growth ◽

Thermal Cvd

ABSTRACTA new concept of Reactive CVD is proposed for the low-temperature growth of thin films by CVD and discussed in terms of general features of such film growth. One demonstrated example of the reactive CVD, called Spontaneous Chemical Deposition, features gas phase reactions of silane with fluorine is outlined in terms of the general characteristics of the film growth and properties.In addition, a second example of reactive CVD, called Reactive Thermal CVD and involving thermal CVD of poly-SiGe from germanium fluoride and disilane, is discussed and low-temperature growth using this method is reviewed.

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Growth of Amorphous and Crystalline Silicon by HR-CVD (Hydrogen Radical Enhanced CVD)

MRS Proceedings ◽

10.1557/proc-95-225 ◽

1987 ◽

Vol 95 ◽

Cited By ~ 49

Author(s):

N. Shibata ◽

K. Fukuda ◽

H. Ohtoshi ◽

J. Hanna ◽

S. Oda ◽

...

Keyword(s):

Thin Films ◽

Gas Phase ◽

Marked Improvement ◽

Crystalline Silicon ◽

Three Dimensional ◽

Active Species ◽

Hole Transport ◽

Gas Phase Reactions ◽

Hydrogen Radical ◽

Si Films

AbstractSystematic studies have been made on preparation of Si thin films from SiF4 under control over the flow of atomic hydrogens. The gas phase reactions taking place in the mixture of fragments (SiFn) resulting from plasma-induced dissociation and atomic hydrogens were widely investigated by a mass spectroscopy. Chemically active species,i.e., SiF2H and SiH2F were found as those related to the growth of films. The growth in the vicinity of substrates involves either endothermic or radical-enhanced reaction for the propagation of the three dimensional Si networks, accompaning release of terminators such as H and F. Accordingly, Si thin films with structures from amorphous to crystalline were obtained by controlling the flow of atomic hydrogen. A marked improvement in the hole-transport was established in the Si films containing hydrogen less than 5–6 at % due to the reduction in the tail states near the valence band.

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