plasma deposition mechanism
Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Abstract A mass spectrometric analysis of the positive ions and neutral products in a silane glow discharge has been performed. The active species, created by dissociation, disproportionation, and ion-molecule reactions are mainly SiH2, SiH3, and H. A calculation of the distribution of the SiH n + ions shows that the silane concentration monitors the abundance of SiH 3 + . The diffusional transport of radicals toward the discharge-tube walls can explain the observed deposition rates. The study of SiH4-SiD4 and SiH4-D2 plasmas emphasizes several reactions which modify the free-radical populations depending on the discharge conditions: disproportionation, termination, recombination, and abstraction. Heterogeneous reactions have also been observed: etching of the film by H atoms and direct incorporation of hydrogen in the growing film. A general scheme for the plasma deposition mechanism is proposed.
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