TY - JOUR
T1 - Optical, composition, durability and environmental properties of microwave plasma assisted sputter deposited silicon nitride
AU - Lindsay, Connor
AU - García Núñez, Carlos
AU - Fleming, Lewis
AU - Brinkley, Ian
AU - Pomfret, Jonathan
AU - Mazur, Michal
AU - Kot, Malgorzata
AU - Zhu, Wenzhong
AU - Saunders, Kirstin
AU - Reid, Stuart
AU - Herguedas, Elen
AU - Redondo-Cubero, Andres
AU - Gibson, Des
PY - 2025/9/30
Y1 - 2025/9/30
N2 - A study is presented of the optical, mechanical, composition, durability, environmental and structural properties of Silicon Nitride thin films deposited at room temperature using a vertical axis rotating drum-based microwave plasma assisted sputter system. The deposited material composition was investigated using both X-ray photoelectron spectroscopy (XPS) and Elastic Recoil Detection Analysis with Time-of-Flight (ERDA-TOF), results indicate layers present a uniform composition with thickness and despite the incorporation of impurities, the Si/N ratio remains close to stoichiometric Si3N4. The deposited material provides homogeneous low dispersion - with a refractive index of approximately 1.98 over a wide transmittance range (350 nm - 5 μm). Additionally, the single layer silicon nitride was found to be durable with a hardness, Youngs modulus and compressive stress of 31 GPa, 240 GPa and – 454 MPa respectively. The coating was subjected to and passed external surface environmental tests covered by MIL-C-48497A durability requirements (adhesion, abrasion and temperature/ humidity cycling) and MIL-C-675C (para 4.5.9) salt spray. Moreover, 10,000 wipes on the TS1888 (para 5.4.3) sand slurry abrasion test achieved with no visible signs of damage. A silicon nitride/ silica multilayer durable broadband visible anti-reflection coating is demonstrated, passing the same range of durability and environmental tests as single layer silicon nitride.
AB - A study is presented of the optical, mechanical, composition, durability, environmental and structural properties of Silicon Nitride thin films deposited at room temperature using a vertical axis rotating drum-based microwave plasma assisted sputter system. The deposited material composition was investigated using both X-ray photoelectron spectroscopy (XPS) and Elastic Recoil Detection Analysis with Time-of-Flight (ERDA-TOF), results indicate layers present a uniform composition with thickness and despite the incorporation of impurities, the Si/N ratio remains close to stoichiometric Si3N4. The deposited material provides homogeneous low dispersion - with a refractive index of approximately 1.98 over a wide transmittance range (350 nm - 5 μm). Additionally, the single layer silicon nitride was found to be durable with a hardness, Youngs modulus and compressive stress of 31 GPa, 240 GPa and – 454 MPa respectively. The coating was subjected to and passed external surface environmental tests covered by MIL-C-48497A durability requirements (adhesion, abrasion and temperature/ humidity cycling) and MIL-C-675C (para 4.5.9) salt spray. Moreover, 10,000 wipes on the TS1888 (para 5.4.3) sand slurry abrasion test achieved with no visible signs of damage. A silicon nitride/ silica multilayer durable broadband visible anti-reflection coating is demonstrated, passing the same range of durability and environmental tests as single layer silicon nitride.
KW - silicon nitride
KW - optical coatings
M3 - Article
SN - 1559-128X
JO - Applied Optics
JF - Applied Optics
ER -
