Open AccessEffect of cladding layer and subsequent heat treatment on hydrogenated amorphous silicon waveguides
Author(s) -
Shiyang Zhu,
GuoQiang Lo,
Weihong Li,
DimLee Kwong
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.023676
Subject(s) - materials science , cladding (metalworking) , annealing (glass) , thermal stability , silicon , amorphous solid , dielectric , passivation , amorphous silicon , optics , waveguide , optoelectronics , composite material , layer (electronics) , crystalline silicon , chemistry , physics , organic chemistry , quantum mechanics
Although intrinsic hydrogenated amorphous silicon (a-Si:H) wire waveguides clad with normal SiO(2) layers have low propagation loss of 2.7 ± 0.1 dB/cm for transverse electric (TE) mode in the 1550-nm range, the transparency degrades when interfaced with other dielectrics (e.g., air) and/or exposed to elevated temperatures due to degradation of surface passivation in the a-Si:H waveguides. The thermal stability of a-Si:H wire waveguides with various cladding layers is systematically investigated, showing that the a-Si:H wire waveguides are stable at annealing temperature lower than ~350°C, while they degrade quickly when annealed at a higher temperature. It indicates that the thermal stability is mainly determined by the annealing temperature rather than the annealing time, which may be attributed to quick evolution of weakly bonded hydrogen in the a-Si:H waveguides. A thin Si(3)N(4) intercladding layer between SiO(2) cladding and a-Si:H waveguide core may degrade transparency due to N-H bond absorption and is of no benefit to the thermal stability, thus its overall effect on the a-Si:H waveguides is detrimental.