Ceramics Products
TaC 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
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 |
Comparison of Electrical Properties of SiC Wafers Grown with TaC-Coated Graphite Crucible and Conventional Graphite Crucible
| Density (gm/cm3) | Emissivity | CTE (× 10-6/K) | Hardness (HK) | Resistance (Ohm-cm) | Thermal Stability | Thickness Variation | Graphite Dimension Change | |
|---|---|---|---|---|---|---|---|---|
|
TaC |
14.3 |
0.3 |
6.3 |
2000 |
1×10-5 |
> 2200°C |
-5% |
-17 µm |
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 |
TaC vs. SiC
| Density (gm/cm3) | Emissivity | CTE (× 10-6/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 |
1×10-5 |
> 2200°C |
0.2 |
0.1 |
-5% |
|
SiC |
3.2 |
0.8 |
4.5 |
2800 |
2×10-3 |
< 1600°C |
1.5 |
1.7 |
-10% |
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
