Study of deposition conditions and hydrogen motion in r. f. sputtered hydrogenated amorphous silicon
Three series of a-Si:H films were prepared by r.f. sputtering in He/H/sub 2/, Ar/H/sub 2/, and Xe/H/sub 2/ atmospheres. The r.f. power used for deposition was varied from 0.27 W/cm/sup 2/ to 3.3 W/cm/sup 2/ for each of these three series. The films were characterized using mechanical thickness, optical transmission, infrared, and electron spin resonance measurements. The deposition rates of these films were found to vary linearly with depositions rates predicted from known sputtering yields. The total hydrogen concentration of the films as a function of deposition rate was found to agree with the predictions of a kinematic model for hydrogen incorporation. The concentration of silicon atoms bonded to more than one hydrogen atom was found to agree with a random statistical model, although, there were fluctuations away from this model's predictions when high r.f. powers were used for deposition. The density of weak Si-Si bonds and the value of the Urbach edge coefficient were used to judge the quality of the films. It was found that samples prepared in an Ar/H/sub 2/ atmosphere at high r.f. powers (>2.2 W/cm/sup 2/) were of the highest quality. These experiments also indicated that silicon-hydrogen bonds in r.f. sputtered a-Si:H are stronger than silicon-hydrogen bonds in glow-discharge-produced a-Si:H.
- Research Organization:
- Iowa State Univ. of Science and Technology, Ames (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 5852865
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMORPHOUS STATE
ATMOSPHERES
CHEMICAL BONDS
CHEMICAL REACTIONS
CONTROLLED ATMOSPHERES
DEPOSITION
ELEMENTS
FILMS
HYDROGENATION
SEMIMETALS
SILICON
SILICON COMPOUNDS
SPUTTERING
THIN FILMS