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Title: Diagnostics of a glow discharge used to produce hydrogenated amorphous silicon films. Final report, February 15, 1980-April 14, 1981

Technical Report ·
OSTI ID:6487661

The glow-discharge deposition apparatus, with mass spectrometer sampling, was constructed and tested with Ar and SiH/sub 4/ gas. It successfully achieved the desired high vacuum (approx. 10/sup -8/ Torr), gas flow rates (200 sccm), and mass spectrometer sensitivities (approx. 1 ppM). Ion and neutral species were measured from the end and side of a dc discharge in SiH/sub 4/, finding major changes with sampling position, gas pressure, and discharge power. These observations were explained qualitatively with a discharge model, based on known electrical characteristics of dc discharges combined with available information and some assumptions regarding silane reaction rates. The ion species from a dc-proximity discharge, and from the end and sides of an rf discharge in SiH/sub 4/ were studied. Qualitative comparisons have been made to the dc discharge results and to approximate models for the fields and charge distributions in rf discharges. Impurity concentrations were studied in the vacuum system and silane gases, with sensitivities of less than or equal to 1 ppM outside of mass regions overlain by SiH/sub 4/ ion spectra. The impurity levels attained in the apparatus appear to be entirely due to impurities in the SiH/sub 4/ gas, and are typically at the 1 to 100 ppM level.

Research Organization:
Colorado Univ., Boulder (USA)
DOE Contract Number:
AC02-77CH00178
OSTI ID:
6487661
Report Number(s):
SERI/TR-9053-1-T3
Country of Publication:
United States
Language:
English