Defect formation during deposition of undoped a-Si:H by PECVD

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:527688

Maeda, Keiji; Umezu, Ikurou ^[1]

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1. Science Univ. of Tokyo, Noda, Chiba (Japan). Dept. of Materials Science and Technology

Dependence of the as-grown defect concentration in PECVD undoped a-Si:H on the deposition parameters, i.e., substrate temperature and precursor density in the plasma produced by H{sub 2} dilution of SiH{sub 4} gas, is investigated. It is found that the defect density behaves similarly to the concentration of SiH{sub 2} configuration in the films deposited at substrate temperatures below 300 C. The defect concentration, however, varies proportionally to about the 3rd to 4th power of the SiH{sub 2} concentration depending on the deposition condition. Based on the surface reaction mechanism proposed in the previous paper, a large enthalpy change is expected to accompany the bimolecular reaction of the adsorbed SiH{sub 3} radicals, which incorporates the SiH{sub 2} configuration into the network. Characteristics of the defect formation caused by the breaking Si-Si bond near the growing surface owing to this energy is compared with those of the Staebler-Wronski effect. Both similarity in dependence on H atom concentration and difference in annealing temperature are discussed. It is concluded that the as-grown defects are most likely formed during deposition owing to the large enthalpy change accompanying the bimolecular surface reaction.

• OSTI ID: 527688
• Report Number(s): CONF-960401--; ISBN 1-55899-323-1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL REACTIONS
CHEMICAL VAPOR DEPOSITION
EXPERIMENTAL DATA
MICROSTRUCTURE
POINT DEFECTS
PRESSURE DEPENDENCE
SILANES
SILICON
SURFACES
TEMPERATURE DEPENDENCE
THIN FILMS