Aluminium Nitride Layers for III-V Nitride Epitaxy and High Frequency Applications
Available AlN templates on SiC:
| Substrate |
4H-SiC or 6H-SiC |
| Substrate Orientation |
On axis (0001) Si face - electrically conducting |
| Substrate Diameter |
2", 3" and 4" |
| AlN Thickness Range |
0.2 to 20µm |
Two types of templates are available:
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Benefits
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AlN on SiC
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Template Properties
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Images
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User benefits to use AlN templates
- Start growth on native AlN surface
- Simplify nucleation process (no buffer layer is needed)
- Reduce defect density in device structure
- Improve device parameters
- Increase epi productivity on existing growth equipment
- Reduce epi cost via throughput and yield increase
- Reduce maintenance cost
- Avoid possible patent contest issues related to buffer layer
Thick crack free AlN on SiC template
Applications: semi-insulating substrate for:
- Power AlGaN/GaN-based High Electron Mobility Transistors ( HEMT)
- Power blue and UV LEDs, and Laser Diodes
Properties:
- High electrical resistivity and thermal conductivity
- Close lattice and thermal match with GaN and AlGaN layers
- Low defect density in device structures
- Thickness of AlN is sufficient to provide reliable insulation and low current leakage
- Fraction of price of semi-insulating SiC
- Positively tested at customers enabling dramatic cost reduction of final HEMT devices
Typical template properties for 10-µm thick AlN layer on 2-inch SiC substrate:
| AlN Thickness |
10µm |
| Thickness variation |
<4% std. deviation |
| Thickness uniformity |
<2% std deviation |
| Dislocation Density (cm-2) |
5 to 9 x 108 |
| FWHM of X-ray w-scan (00.2), arcsec |
<450 |
| Surface Morphology |
As grown or polished (typical av. RMS <0.5nm) |
| Doping |
Undoped |
| Electrical Resistivity (W-cm) |
>1010 (@300k) and >107 (@500k) |
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AlN (20 µm) on 4-inch SiC |
Electrical Resistivity of AlN Layer |