Properties of amorphous hydrogenated silicon-tin alloys prepared by radio frequency sputtering

Journal Article · Sun Apr 15 04:00:00 EST 1984 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.333320· OSTI ID:5222703

Williamson, D L; Kerns, R C; Deb, S K

Amorphous Si/sub 1-x/Sn/sub x/ and Si/sub 1-x/Sn/sub x/ :H (0< or =x< or =0.3) alloy films have been prepared by radio frequency sputtering from composite Si--Sn targets in Ar or Ar-10% H/sub 2/ mixtures at dynamic pressures of 4 or 20 mTorr. The structural characteristics of the alloys have been probed with /sup 119/Sn conversion electron Moessbauer spectroscopy, x-ray diffraction, and infrared absorption. Most of the tin goes into tetrahedral substitutional Si sites at 4 mTorr whereas significant fractions of crystalline ..beta..-Sn are produced at 20 mTorr. The substitutional Sn Moessbauer resonance is systematically characterized with a Lorentzian doublet line shape. Oxygen contamination increases with increasing Sn content in the 20-mTorr films but is attributed to postdeposition oxidation. No evidence is found for Sn--H bonds or interstitial (nonbonded) Sn. The optical band-gap decreases at a rate of -0.056 eV/at. % Sn for alloys containing little or no ..beta..-Sn and for x up to 0.13. Both the optical band gap and the Moessbauer isomer shift extrapolate to ..cap alpha..-Sn (grey tin) behavior at xapprox. =0.3--0.4. The electrical conductivity increases with x at a rate which is not consistent with the measured reduction in band gap and a fixed relative Fermi level. This and the temperature dependence of the conductivity suggest a transition from extended state free-carrier conduction to localized state hopping conduction.

• Research Organization: Physics Department, Colorado School of Mines, Golden, Colorado 80401
• DOE Contract Number: AC02-77CH00178
• OSTI ID: 5222703
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 55:8; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation &amp; Manufacture
360602 -- Other Materials-- Structure &amp; Phase Studies
360603 -- Materials-- Properties
ABSORPTION SPECTRA
ALLOYS
AMORPHOUS STATE
ANNEALING
CHEMICAL REACTIONS
COHERENT SCATTERING
DAYS LIVING RADIOISOTOPES
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EVEN-ODD NUCLEI
FILMS
HEAT TREATMENTS
HYDROGENATION
INFRARED SPECTRA
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MOESSBAUER EFFECT
NUCLEI
PHYSICAL PROPERTIES
RADIOISOTOPES
RF SYSTEMS
SCATTERING
SILICON ALLOYS
SPECTRA
SPUTTERING
STABLE ISOTOPES
THIN FILMS
TIN 119
TIN ALLOYS
TIN ISOTOPES
VISIBLE SPECTRA
X-RAY DIFFRACTION