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Title: Properties of reactively-deposited SiC and GeC alloys

Conference ·
OSTI ID:6952020

Thin-film silicon carbide (Si{sub x}C{sub 1-x}) and germanium carbon (Ge{sub x}C{sub 1-x}) alloy coatings with low infrared optical absorption have been fabricated by dc- and rf-reactive magnetron sputtering. The optical and mechanical properties of the coatings depend on composition determined by deposition conditions. The refractive index and optical absorption coefficient of Si{sub x}C{sub 1-x} alloys were varied from those of amorphous SI to those near diamond-like carbon (DLC) by increasing C content. The band edge shifted below 1.2 eV with C content as high as 0.8. The useful range of the Si{sub x}C{sub 1-x} coatings was extended to wavelengths as low as 1 {mu}m. The useful transparency range of Ge{sub x}C{sub 1-x} coatings is from 3 to 12 {mu}m. The refractive index of Ge{sub x}C{sub 1-x} coatings was varied from 4.2 of amorphous Ge to near 3.4 by increasing x from 0 to 0.5. The optical absorption coefficient was a complex function of composition and C-H, Ge-H, and Ge-C bonding. Mechanical stress in both materials was generally moderate, and increased with increasing C content for the GeC alloys and decreased with increasing C or the SiC alloys. The wide range of optical properties obtainable for both coating types makes them useful in many types of multilayer designs. Abrasion-resistant infrared (IR) multispectral antireflection coatings on zinc sulfide (ZnS) were demonstrated using Ge{sub 0.9}C{sub 0.1} and DLC layers. 6 refs., 6 figs., 2 tabs.

Research Organization:
Pacific Northwest Lab., Richland, WA (USA)
Sponsoring Organization:
USDOD; DOE/NE
DOE Contract Number:
AC06-76RL01830
OSTI ID:
6952020
Report Number(s):
PNL-SA-17876; CONF-900756-35; ON: DE90016363
Resource Relation:
Conference: SPIE's international symposium on optical and optoelectronic applied science and engineering exhibit, San Diego, CA (USA), 8-13 Jul 1990
Country of Publication:
United States
Language:
English