LIGO Document G1500194-v2
- Chemical Vapor Deposition (CVD) method is well-established in silicon IC industry. Deposition of silica(SiO2) , silicon-nitride(SiNx) and amorphous silicon(α-Si) films on 16” (40cm) silicon wafer is a common practice nowaday. All-CVD process for depositing quarter-wave (QW) stacks for dielectric mirror that consists of high index layer, e.g. α-Si and SiNx, and low index layer, e.g. SiO2 and SiNx, has advantages for LIGO application and yet not been realized. In this poster, we present results of optical and mechanical properties of un-annealed SiO2 film deposited by Plasma-enhanced Chemical Vapor Deposition (PECVD) on silicon substrate. Refractive index of the film was 1.45 and extinction coefficient was less than detection limit (~10-3 for ellipsometry) at 1550nm wavelength. Young’s modulus and stress of the film are 83.8±1.3GPa and -158.2±6.0MPa respectively. Un-annealed mechanical loss was (4.76±1.16)*10-4 , this value is close to that of the SiO2 film deposited by ion beam sputter in our laboratory. Annealing effect will be explored.
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