ZECOAT CORPORATION 23510 Telo Ave. #3 Torrance, CA 90505

Advanced Vacuum Coating Solutions               Aerospace, Defense & Astronomy

Silicon Cladding for Lightweight Mirrors



ZeCoat manufactures an amorphous silicon cladding based on a pulsed ionization process. In this low temperature process (<100°C), silicon is heated by an electron beam and evaporated. The evaporating silicon is bombarded periodically by a flux of argon ions. The argon ions compact the silicon layer rendering the layer compressively stressed. Silicon films made without ion bombardment are stressed in tension. By balancing the tensile and compressive properties of the films, a thick silicon layer (>100-microns) may be deposited with little net-coating stress. The resulting silicon layer is also highly polishable. 

Specifications:

Stress = < 85-MPa (low-stress)

Polishable = < 2-angstroms RMS (highly polishable)

Process Temperature = < 100°C (suitable for low temperature plastics)

Substrate Size =  up to 1.15-meters in diameter currently. Process is scaleable to mirrors 2+ meters in diameter

Applications: 

A future lightweight segmented space telescope with polished silicon carbide segments represents one potential application for the technology. Other potential applications include: graphite composite RF reflectors, lightweight plastic mirrors, thin film solar cells, and x-ray mirror structures. 
Measuring stress of silicon cladding coating is calculated by measuring the change in curvature of a coated optical flat
Wave= -0.49673 to +0.49673
Measured stress of the silicon cladding coating is calculated by measuring the change in curvature of a coated optical flat.
samples coated at ZeCoat Corporation with 25-microns of silicon cladding
Samples coated at ZeCoat Corporation with 25-microns of silicon cladding.
Artist rendition of a future lightweight segmented space telescope
A future lightweight segmented space telescope with polished silicon carbide  segments represents one potential application for the technology.