Silicon Nitride (SiN) on Silicon Wafers 

What Is Silicon Nitride (SiN) on Silicon?

Silicon nitride (commonly SiN or Si3N4) is a durable dielectric thin film deposited onto silicon wafers to provide electrical insulation, chemical resistance, and mechanical strength. In microfabrication, SiN is frequently selected as a robust masking layer for wet etching and as a structural film for MEMS devices where controlled stress matters.

LPCVD vs PECVD Silicon Nitride

LPCVD nitride is typically chosen for dense, high-quality films with strong repeatability—especially when thermal budgets allow higher processing temperatures. PECVD nitride is often used when lower temperature processing is required. If you’re not sure which deposition route fits your process flow, send your constraints (max temperature, target stress, thickness, and side coating) and we’ll guide the best option.

Stoichiometric LPCVD Nitride

Stoichiometric LPCVD nitride can be a very effective insulator and works well as a KOH etch mask, particularly when deposited over thermal oxide. It’s also commonly used in MEMS and in defining active regions during field oxidation.

Stoichiometric LPCVD Nitride Specifications

• Thickness range: 100Å – 4500Å
• Sides processed: both
• Refractive index: 2.00 ± 0.05 @ 632nm
• Film stress: >800 MPa tensile
• Wafer size: 2"–8"
• Temperature: ~800°C
• Gases: dichlorosilane, ammonia

Low Stress LPCVD Nitride

Low stress nitride is popular for membranes, cantilever beams, and other mechanical structures in MEMS, while still being effective as a KOH mask. This option is often chosen when you want strong nitride functionality but need reduced risk of wafer bowing or cracking at higher thickness.

Low Stress Nitride Specifications

• Thickness range: 50Å – 2µm
• Thickness tolerance: ±5%
• Within-wafer uniformity: ±5% or better
• Wafer-to-wafer uniformity: ±5% or better
• Sides processed: both
• Refractive index: 2.20 ± 0.02
• Film stress: <250 MPa tensile
• Wafer size: 50mm–200mm
• Wafer thickness: 100µm–2000µm
• Wafer material: Silicon, SOI, Quartz
• Temperature: ~820°C
• Gases: dichlorosilane, ammonia

Super Low Stress LPCVD Nitride

Super low stress nitride is engineered for applications requiring extremely low film stress and thicker depositions. This option can be used when conventional nitride films risk cracking or peeling as thickness increases.

Super Low Stress Nitride Specifications

• Thickness range: 50Å – 2µm (custom thicker options may be available)
• Thickness tolerance: ±5%
• Within-wafer uniformity: ±5% or better
• Wafer-to-wafer uniformity: ±5% or better
• Sides processed: both
• Refractive index: 2.30 ± 0.05
• Film stress: <100 MPa tensile
• Wafer size: 50mm–200mm
• Wafer thickness: 100µm–2000µm
• Wafer material: Silicon, SOI, Quartz
• Temperature: ~820°C
• Gases: dichlorosilane, ammonia

Targeted-Stress LPCVD Nitride

If your device requires a specific stress window, targeted-stress LPCVD nitride uses controlled gas ratios and stable process settings to dial in film stress to your application. This is a strong option for repeat builds where mechanical behavior and wafer flatness are critical.

Targeted-Stress Nitride Specifications

• Thickness range: 50Å – 4µm
• Thickness tolerance: ±5%
• Within-wafer uniformity: ±5% or better
• Wafer-to-wafer uniformity: ±5% or better
• Sides processed: both
• Refractive index: 2.05 – 2.35
• Film stress: your target ±50 MPa tensile
• Wafer size: 50mm–200mm
• Wafer thickness: 100µm–2000µm
• Wafer material: Silicon, SOI, Quartz
• Temperature: ~800–820°C
• Gases: dichlorosilane, ammonia

Related Silicon Nitride Resources

• Silicon Nitride LPCVD & PECVD Wafer Deposition
• Stoichiometric Silicon Nitride LPCVD Wafers
• Low Stress Nitride on Silicon Wafers
• Super Low Stress Silicon Nitride Wafers
• Thermal Oxide Deposition on Silicon Wafers
• Silicon Wafers