Effect of hydrogen on the microstructural, optical, and electronic properties of a-Si:H thin films deposited by direct current magnetron reactive sputtering

Journal Article · Mon May 01 00:00:00 EDT 1989 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.576256· OSTI ID:6182224

Pinarbasi, M; Maley, N; Kushner, M J; Myers, A; Abelson, J R; Thornton, J A

Device quality hydrogenated amorphous silicon (a-Si:H) films have been deposited under a wide range of deposition conditions using dc magnetron reactive sputtering. The total hydrogen content (C/sub H/) has been varied from 0 to /similar to/40 at. % by changing the substrate temperature (T/sub s/) or hydrogen partial pressure (P/sub =/) independent of other deposition parameters. The films that contain C/sub H/ between 10 and 28 at. % have the highest quality. The optical band gap (E/sub g/) varies linearly with C/sub H/ for all deposition conditions studied. With increasing C/sub H/ the dark conductivity at 300 K decreases from /similar to/1 x 10/sup -4/ to /similar to/1 x 10/sup -12/ (..cap omega.. cm)/sup -1/; however, the photoconductivity under AM-1 illumination, for the highest quality films, remains in the 0.8--3.5 x 10/sup -5/ (..cap omega.. cm)/sup -1/ range. The dark conductivity activation energy (E/sub a/) was measured to determine the Fermi-level (E/sub f/) position with respect to the conduction band (E/sub c/) and a linear correlation between E/sub g/ and E/sub a/ is found for high-quality films. The films having low hydrogen content (10<17 at. %) are slightly n-type and become intrinsic as C/sub H/ is increased. The subgap density of states diminishes with the increase in E/sub c/-E/sub f/ (taken to be E/sub a/ ) as the films become intrinsic. In short, the microstructural, optical, and electronic properties of these films vary monotonically with the total hydrogen content.

• Research Organization: Department of Materials Science and Engineering, and the Coordinated Science Laboratory, University of Illinois, Urbana, Illinois 61801
• OSTI ID: 6182224
• Journal Information: J. Vac. Sci. Technol., A; (United States), Vol. 7:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
HYDROGEN ADDITIONS
DEPOSITION
ELECTRICAL PROPERTIES
MICROSTRUCTURE
OPTICAL PROPERTIES
SILICON
AMORPHOUS STATE
CARRIER LIFETIME
ELECTRIC CONDUCTIVITY
ELECTRON DRIFT
ELECTRON MOBILITY
EXPERIMENTAL DATA
FERMI LEVEL
HYDROGENATION
IMPURITIES
MAGNETRONS
PARAMETRIC ANALYSIS
PHOTOCONDUCTIVITY
SPUTTERING
THIN FILMS
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DATA
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
ENERGY LEVELS
EQUIPMENT
FILMS
INFORMATION
LIFETIME
MICROWAVE EQUIPMENT
MICROWAVE TUBES
MOBILITY
NUMERICAL DATA
PARTICLE MOBILITY
PHYSICAL PROPERTIES
SEMIMETALS
360602* - Other Materials- Structure &amp; Phase Studies
360603 - Materials- Properties