US 12,422,605 B2
Near infrared optical interference filters with improved transmission
Robert Sprague, Acton, MA (US); and Shengyuan Bai, Shanghai (CN)
Assigned to MATERION CORPORATION, Mayfield Heights, OH (US)
Filed by Materion Corporation, Mayfield Heights, OH (US)
Filed on Jun. 8, 2022, as Appl. No. 17/835,495.
Application 17/835,495 is a continuation of application No. 16/357,698, filed on Mar. 19, 2019, granted, now 11,372,144.
Application 16/357,698 is a continuation of application No. 15/046,889, filed on Feb. 18, 2016, abandoned.
Claims priority of provisional application 62/117,598, filed on Feb. 18, 2015.
Prior Publication US 2022/0299688 A1, Sep. 22, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 5/28 (2006.01); C23C 14/06 (2006.01); C23C 14/10 (2006.01); C23C 14/14 (2006.01); C23C 14/34 (2006.01); G02B 1/10 (2015.01)
CPC G02B 5/281 (2013.01) [C23C 14/06 (2013.01); C23C 14/0652 (2013.01); C23C 14/10 (2013.01); C23C 14/14 (2013.01); C23C 14/3414 (2013.01); C23C 14/3457 (2013.01); G02B 1/10 (2013.01); G02B 5/285 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method of manufacturing an interference filter comprising alternating amorphous hydrogenated silicon with added nitrogen (a-Si:H,N) and silicon-based dielectric layers, the method comprising:
sputtering silicon from a silicon target onto a filter substrate; and
during the sputtering, alternating between:
(i) a process gas including hydrogen and nitrogen to deposit a-Si:H,N having a refractive index in the range 3.3 to 3.5 inclusive to form each a-Si:H,N layer; and
(ii) at least one of a process gas including oxygen to deposit silicon suboxide (SiOx), a process gas including oxygen and nitrogen to deposit silicon oxynitride (SiOxNy), or a process gas including nitrogen to deposit silicon nitride (Si3N4) to form each silicon-based dielectric layer;
wherein the a-Si:H,N layers have an atomic concentration of hydrogen between 4% and 8% and an atomic concentration of nitrogen between 2% and 12%;
wherein the silicon-based dielectric layers have a refractive index lower than a refractive index of the a-Si:H,N, and wherein at least one of the silicon-based dielectric layers has a refractive index in the range 1.9 to 2.7 inclusive.