SiC Material – Characteristics and Benefits
SiC Material outperforms other semiconductor materials such as Silicon or Gallium Nitride in several areas:
- Higher band-gap energy
- Higher breakdown electric field
- Higher thermal conductivity
- Higher saturation electron drift velocity
- Higher radiation tolerance
SiC Material based electronic devices therefore provide the advantage of:
- Higher breakdown voltage
- Higher current density
- Higher operating temperature
- Higher switching frequency
- Higher energy efficiency or lower power losses
Electronic Systems which are designed by using SiC based devices outperform traditional Systems with:
- Larger power capacity
- Higher power efficiency
- Higher reliability and lifetime
- Less complex and less expensive cooling requirements
- Lower amount of passive components
- Smaller system size
- Lower Life-cycle costs
Norstel SiC Production Process – Crystal growth
Growth of SiC is the core of Norstel’s technology. For crystal growth, Norstel uses and develops two techniques:
- the High Temperature Chemical Vapor Deposition (HTCVD) technique
- the seeded sublimation technique
Norstel SiC Production Process – HTCVD
The patented HTCVD concept was conceived in 1995 and has since then been a focus of our R&D efforts. HTCVD crystals are directly grown from purified gases at temperatures above 2000 degrees. In particular, the HTCVD technique has intrinsic advantages to grow high purity crystals for producing semi-insulating wafers and gemstones.
We believe that by mastering HTCVD, we can produce high-quality large-diameter SiC crystals in a very cost-efficient way, thereby opening new markets and applications. For example, by using doping techniques similar to epitaxy, HTCVD has demonstrated p-type wafers.
Norstel SiC Production Process – Sublimation
In the well-established seeded sublimation technique (also known as Physical Vapor Transport), SiC crystals are grown at temperatures above 2000 degrees from a polycrystalline powder source. Norstel uses and develops this technique to produce n-type wafers for power devices.
Norstel SiC Production Process – Epitaxy
SiC devices require growth of one or several SiC epitaxial layers onto the substrate. These layers are grown in a hot-wall CVD system at ca. 1600C. Norstel uses both multi-wafer and single wafer systems. The typical thickness ranges from 5 to 30 micrometers and the doping can be either n- or p-type. On customer request thicker layers are possible as well. Multiple layers with different doping levels and conductivity types can also be grown for advanced device designs. In addition to the thickness and electrical properties, the defect density in the epitaxial layer is critical to make high performance devices at a high yield.