Ceramics Products

Carbide Coatings

Extreme thermal stability and chemical resistance

Momentive Technologies’ unique carbide coatings provide exceptional protection for graphite in harsh semiconductor and compound semiconductor material processing. The results are extending graphite component life, maintaining reaction stoichiometry and suppressing impurity migration into epitaxy and crystal growth applications to provide improved yield and quality benefits.

Features and Benefits

  • Temperature stability over 2000°C enables ultra-high temperature operation
  • Resistance to H2, NH3, SiH4, and Si provides protection in harsh chemical environments
  • Resistance to thermal shock accelerates operation cycles
  • Strong adhesion to graphite ensures long life without coating delamination
  • Ultra-high purity eliminates unwanted impurities or contaminations
  • Conformal coating coverage achieves tight dimension tolerance

Our Tantalum Carbide (TaC) and Niobium Carbide (NbC) coatings guard key furnace and reactor components at elevated temperatures (up to 2200°C) against hot ammonia, hydrogen and silicon vapors and molten metals. Momentive Technologies can provide our coating either as a toll-coating or on a full-service basis thanks to our extensive graphite machining and measurement capabilities to handle your customized requirements, and our team of expert engineers is always here to help you design the right solutions for you and your specific applications.

Carbide Coatings

Comparison of Tac Coating and Purified Research-Grade Graphite

B N O Si S Cl Nb
TaC
<0.01
15
40
<0.01
<0.01
14
14
Graphite
1
480
260
2
5
2
<0.01
Typical values.

Comparison of Electrical Properties of SiC Wafers Grown with TaC-Coated Graphite Crucible and Conventional Graphite Crucible

Density (gm/cm3) Emissivity CTE (xl0-6/K) Hardness (HK) Resistance (Ohm-cm) Thermal Stability Thickness Variation Graphite Dimension Change
TaC
14.3
0.3
6.3
2000
1x10-5
>2200°C
-5%
-17µm
Typical values.

Typical Physical Properties of Tac Coating

Bulk Concentration Bulk Resistivity Mobility
TaC
8 x 1015/cm
4.5 ohm-cm
237 cm2/Vs
Graphite
5 x 1017/cm
0.1 ohm-cm
151 cm2/Vs
Typical values.

TaC vs. SiC

Density (gm/cm3) Emissivity CTE (xl0-6/K) Hardness (HK) Resistance (Ohm-cm) Thermal Stability Etch Rate in NH3(µm/hr) Etch Rate in H2(µm/hr) Thickness Variation
TaC
14.3
0.3
6.3
2000
1x10-5
>2200°C
0.2
0.1
-5%
SiC
3.2
0.8
4.5
2800
2x10-3
<1600°C
1.5
1.7
-10%
Typical values.

The information provided in these charts is for informational purposes only. It is not a product or material recommendation and it is shared with you on the express condition that you will use your own expertise and professional judgment in applying any information to a specific use case or need. This is general information only, the validity of which may be affected by individual factors that are unknown to Momentive Technologies. It is the responsibility of those using this information to ensure appropriate interpretation and application is undertaken with regards to any specific situation.

Potential Applications

  • GaN and SiC Epitaxial CVD reactor components, including wafer carriers, satellite disks, showerheads, ceilings and susceptors
  • SiC, GaN and AlN crystal growth components, including crucibles, seed holders, guide rings and filters
  • Industrial components, including resistive heating elements, injection nozzles, masking rings, and brazing fixtures

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Carbide Coatings

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