Silicon Carbide (SiC) Wafers and Substrates 

Silicon Carbide Wafers for Research and Device Development

Silicon carbide (SiC) wafers are wide-bandgap semiconductor substrates used in power electronics, RF and microwave devices, epitaxial growth, sensors, radiation detectors, MEMS, thermal research, and other advanced semiconductor applications. UniversityWafer supplies SiC substrates for research, development, prototyping, and specialized device fabrication.

Available options may include 4H-SiC and 6H-SiC wafers, N-type and semi-insulating material, different wafer diameters and thicknesses, single-side or double-side polished surfaces, Si-face or C-face requirements, on-axis or off-axis orientations, and epi-ready surfaces.

Because SiC wafer requirements vary significantly between applications, researchers should specify the polytype, conductivity type, orientation, thickness, surface finish, resistivity, quantity, and intended application when requesting a quote.

150mm and 200mm Silicon Carbide Wafers

UniversityWafer supplies larger-diameter 4H silicon carbide wafers for semiconductor research and device development. These substrates are especially relevant to power electronics, electric-vehicle systems, RF devices, epitaxy, wafer-scale processing, and advanced semiconductor research.

For diameter-specific information, visit our 150mm silicon carbide wafers and 200mm silicon carbide wafers pages.

4H vs 6H Silicon Carbide Wafers

Silicon carbide can form many different crystal structures known as polytypes. Two important hexagonal polytypes used as semiconductor substrates are 4H-SiC and 6H-SiC. Their different stacking sequences produce different electronic properties, which can influence substrate selection.

What Are 4H Silicon Carbide Wafers?

4H-SiC is a hexagonal polytype of silicon carbide and one of the most important SiC materials for modern semiconductor research. Its wide bandgap, high critical electric field, thermal conductivity, and useful carrier transport properties make it attractive for high-power, high-voltage, high-frequency, and high-temperature electronic devices.

Research applications for 4H-SiC include:

• SiC MOSFETs and power transistors
• Schottky barrier diodes
• High-voltage power devices
• Electric-vehicle power electronics
• RF and microwave structures
• High-temperature sensors
• Radiation detectors
• SiC homoepitaxy
• GaN epitaxial growth

Depending on the application, researchers may require N-type conductive substrates or semi-insulating 4H-SiC.

What Are 6H Silicon Carbide Wafers?

6H-SiC is another hexagonal SiC polytype used in semiconductor, optical, thermal, sensor, and materials-science research. Although 4H-SiC is commonly selected for many modern power-device applications, 6H-SiC remains useful when its particular crystal structure and electronic or optical properties are required.

Researchers may use 6H-SiC for optoelectronic studies, spectroscopy, high-temperature research, sensors, thermal applications, and specialized semiconductor experiments. Conductive and semi-insulating material may be available depending on the required specifications.

N-Type and Semi-Insulating Silicon Carbide Wafers

The electrical behavior of the substrate is an important part of SiC wafer selection. N-type SiC is commonly produced using nitrogen doping and provides an electrically conductive substrate for electronic-device and epitaxial research.

Semi-insulating SiC wafers provide high electrical resistivity. They are useful when researchers need to reduce electrical conduction through the substrate, including RF, microwave, isolation, GaN-on-SiC, and specialized sensor applications.

Resistivity requirements should be specified when requesting semi-insulating material because the appropriate value depends on the device or experiment.

Important Silicon Carbide Wafer Specifications

Diameter alone does not determine whether a SiC wafer is appropriate for an experiment. Researchers should consider the complete substrate specification.

• Polytype: 4H-SiC, 6H-SiC, or another required structure
• Diameter: specify the wafer diameter required by the process
• Thickness: standard or custom thickness depending on availability
• Conductivity: N-type, semi-insulating, or another required type
• Dopant: such as nitrogen when applicable
• Resistivity: particularly important for conductive and semi-insulating material
• Orientation: on-axis or required off-axis orientation
• Wafer face: Si-face or C-face when relevant
• Polish: SSP, DSP, CMP, or epi-ready surface
• Surface roughness: specify when critical to deposition or epitaxy
• Flatness: TTV, bow, and warp requirements
• Defect requirements: specify limits when crystal defects are critical
• Grade: research, production, mechanical, dummy, or other available grade

Silicon Carbide Wafers for Power Devices

One of the most important applications of 4H-SiC is the development of high-power and high-voltage semiconductor devices. Compared with silicon, SiC has a wider bandgap and a substantially higher critical electric field, which enables appropriately designed devices to support high voltages with comparatively thin drift regions.

SiC also offers high thermal conductivity, which helps with heat removal in high-power systems. These properties make SiC important for research involving MOSFETs, Schottky diodes, inverters, converters, power modules, renewable-energy systems, industrial motor drives, and electric vehicles.

Researchers developing power devices may require more than a bare SiC substrate. Epitaxial structures can include carefully controlled N-type and P-type layers with specific thicknesses and doping concentrations.

Research Example: 4H-SiC Heterostructures for High-Power Devices

A postdoctoral researcher working on silicon-carbide-based high-power devices requested custom 4H-SiC heterostructures containing multiple epitaxial layers. The requested structures included an N-type 4H-SiC substrate followed by alternating N-type and P-type layers with controlled thickness and carrier concentrations.

The researcher also needed evaluation of the transition between layers with significantly different doping concentrations. This illustrates why substrate type, epitaxial thickness, dopant concentration, interface design, and growth feasibility should all be considered when specifying SiC material for advanced power-device research.

Reference #240956 for specifications and pricing.

Silicon Carbide Substrates for RF and Microwave Research

Semi-insulating SiC is useful for RF and microwave semiconductor structures because high substrate resistivity can help reduce unwanted electrical conduction through the substrate.

The combination of electrical isolation and useful thermal properties also makes semi-insulating SiC an important substrate for certain high-frequency device structures and GaN epitaxy.

Researchers working in this area may also be interested in our RF semiconductor research and microwave photonics resources.

Silicon Carbide Substrates for GaN Epitaxial Growth

SiC is an important substrate platform for gallium nitride (GaN) epitaxial structures. GaN-on-SiC is particularly important in research involving RF, microwave, high-frequency, and high-power semiconductor devices.

Substrate requirements for epitaxial growth may include the SiC polytype, diameter, resistivity, crystal orientation or off-cut, Si-face or C-face, surface roughness, polishing process, and defect requirements.

Researchers should specify whether an epi-ready surface is required when requesting SiC substrates intended for epitaxial deposition.

Silicon Carbide Wafers Used as Heat Spreaders

SiC substrates can also be useful in thermal-management research because of their thermal conductivity and mechanical properties. Applications that use a wafer primarily as a heat spreader or heat sink may not require the same electrical or defect specifications as semiconductor-device-grade material.

For example, a PhD researcher requested ten 6H semi-insulating single-crystal SiC wafers for heat-spreader research with the following requirements:

• Diameter: 2 inches
• Thickness: approximately 330 µm ± 25 µm
• Double-side polished
• Surface roughness below 1 µm on both surfaces
• No specific micropipe-density requirement
• Dummy, mechanical, or rejected grade acceptable

This is a good example of how lower-cost mechanical or dummy-grade SiC may be appropriate when semiconductor-grade electrical performance is not required.

Reference #228485 for specifications and pricing.

SiC Wafers for Sensors and Harsh Environments

Silicon carbide is attractive for sensor research involving elevated temperatures, radiation, mechanical loading, or chemically demanding environments. Depending on the device design, the SiC wafer may function as an active semiconductor, an epitaxial platform, or a mechanically robust substrate.

Research areas include:

• Temperature sensors
• Pressure sensors
• Strain sensors
• MEMS structures
• Radiation detectors
• Harsh-environment electronics
• High-temperature semiconductor devices

4H-SiC for van der Pauw Sensor Research

Researchers have investigated epitaxial 4H-SiC structures for van der Pauw strain-sensor applications. In this type of research, important specifications can include substrate orientation, off-cut angle, epitaxial-layer thickness, conductivity type, dopant, and carrier concentration.

One research configuration used a 4H-SiC substrate with an epitaxial P-type layer and an N-type buffer layer. This type of application demonstrates why researchers should provide the complete device-layer structure rather than requesting only a generic SiC wafer.

SiC Substrates for Surface Acoustic Wave Devices

Silicon carbide can also serve as a substrate in surface acoustic wave (SAW) device research. One researcher requested a SiC substrate with an aluminum nitride (AlN) thin film for the fabrication of interdigital transducer electrodes.

The requested research structure included:

• High-purity semi-insulating SiC substrate
• Approximately 350 µm substrate thickness
• Double-side polished SiC
• Approximately 2 µm AlN thin film
• Subsequent photolithography
• IDT electrode deposition
• Final device dicing

Multilayer structures such as AlN-on-SiC are investigated for resonators, filters, pressure sensors, and other acoustic devices where substrate thermal and mechanical properties can influence device performance.

Reference #265045 for specifications and pricing.

Silicon Carbide Wafers for Radiation Detector Research

SiC is studied for radiation-detection applications because wide-bandgap semiconductor properties can support low leakage current, high-temperature operation, and operation in radiation-intensive environments. 4H-SiC epitaxial structures have been investigated for particle, neutron, X-ray, and other radiation-detector concepts.

Detector performance depends on much more than the bulk substrate. Researchers may need to specify epitaxial-layer thickness and doping, contact structure, active-area geometry, defect density, and electrical properties in addition to the underlying SiC wafer.

SiC radiation-device research is therefore best approached by specifying the complete intended detector structure rather than selecting material based only on wafer diameter.

Example 6H Semi-Insulating SiC Wafer Specifications

A university researcher interested in the optoelectronic properties of 6H-SiC requested a high-resistivity, double-side polished substrate. An example specification for this type of research included:

• Material: High-purity single-crystal silicon carbide
• Polytype: 6H-SiC
• Orientation: On-axis <0001>
• Diameter: Approximately 50.8 mm (2 inch)
• Thickness: Approximately 330 or 430 µm, depending on availability
• Conductivity: Semi-insulating
• Resistivity: High-resistivity material
• Si-face: CMP / epi-ready polished
• C-face: Optical polish or other available finish
• Polish: SSP or DSP depending on research requirements

Specifications and availability can vary, so researchers should provide their required tolerances rather than assuming that every SiC wafer follows the same specification.

Silicon Carbide Benefits Compared with Silicon

Silicon carbide and silicon serve different semiconductor requirements. Silicon remains the dominant substrate for integrated circuits, MEMS, sensors, photovoltaics, and many other semiconductor technologies. SiC becomes especially attractive when a device requires wide-bandgap behavior, high electric-field capability, thermal performance, or operation under demanding conditions.

Important SiC material characteristics include:

• Wider bandgap than silicon
• Higher critical electric field
• High thermal conductivity
• Potential for high-temperature electronic operation
• Useful properties for high-voltage power devices
• Suitability for harsh-environment semiconductor research

These properties can enable power devices with lower losses, higher operating voltages, or different thermal-management requirements than comparable silicon-based device architectures. However, the actual advantage depends on the device design, voltage class, fabrication process, packaging, cooling, and system requirements.

Learn more about silicon wafers for semiconductor research.

Silicon Carbide Wafers for Electric Vehicle Power Electronics

SiC power devices are widely researched for electric-vehicle traction inverters, onboard chargers, DC-DC converters, charging systems, and other high-power conversion applications.

The high critical electric field of SiC is particularly valuable in high-voltage device structures, while its thermal conductivity can assist thermal management. Faster switching capability can also enable designers to use higher switching frequencies in suitable power-conversion systems.

The SiC wafer itself is the starting substrate. Final system performance also depends on epitaxial design, device architecture, contacts, gate structures, packaging, thermal interfaces, and power-electronics design.

Silicon Carbide MOSFET Research

SiC MOSFETs are an important area of wide-bandgap power semiconductor research. Most modern SiC power MOSFET research uses 4H-SiC because of its combination of electronic properties and established substrate and epitaxial technology.

Researchers studying SiC MOSFETs may need N-type substrates with specific resistivity, off-axis orientation, surface preparation, and epitaxial layers engineered for the intended voltage and device structure.

Visit our MOSFET research page for additional semiconductor-device information.

What Is 3C Silicon Carbide?

3C-SiC, also called cubic silicon carbide, differs structurally from the hexagonal 4H and 6H polytypes. It is of research interest for MEMS, sensors, electronics, photonics, and SiC-on-silicon structures.

One reason 3C-SiC is particularly interesting is that epitaxial 3C-SiC can be grown on silicon, offering potential integration with established silicon processing. However, lattice and thermal-expansion mismatch between 3C-SiC and silicon can introduce defects and stress, making material quality an important research challenge.

3C-SiC should therefore be treated separately from bulk 4H-SiC and 6H-SiC substrate selection. Researchers requesting 3C-SiC should specify whether they require a bulk substrate, epitaxial film, or SiC-on-silicon structure.

How Are Silicon Carbide Wafers Made?

Bulk single-crystal SiC used for semiconductor wafers is commonly grown by physical vapor transport (PVT), also known as sublimation growth. At high temperature, SiC source material generates vapor species that are transported through the growth environment and crystallize on a SiC seed.

Controlling temperature, growth conditions, seed orientation, and material purity is important because crystal defects introduced during boule growth can influence the quality of the final wafer.

After the SiC crystal boule is grown, wafer manufacturing generally includes:

1. Slicing the boule into individual wafers
2. Grinding and edge processing
3. Lapping or other planarization steps
4. Surface polishing
5. Chemical-mechanical polishing when an epi-ready surface is required
6. Cleaning and inspection
7. Final characterization and packaging

SiC is mechanically hard, so wafer slicing and polishing present different manufacturing challenges from conventional silicon-wafer processing.

SiC Epi-Ready Surfaces

Researchers planning epitaxial growth should pay particular attention to surface preparation. An epi-ready SiC wafer is processed to provide a surface suitable for subsequent epitaxial deposition.

Relevant specifications may include surface roughness, polishing method, wafer face, crystal orientation, off-cut angle, surface damage, cleanliness, and defect requirements. These parameters can influence subsequent epitaxial growth and device fabrication.

Custom Silicon Carbide Wafers for University Research

Not every research project requires a standard production-grade SiC wafer. University researchers frequently request unusual combinations of diameter, thickness, orientation, resistivity, polishing, epitaxial layers, or mechanical grade.

Applications that use SiC primarily as a mechanical or thermal substrate may be able to use dummy or mechanical-grade material, while semiconductor-device and epitaxial research may require substantially tighter surface, electrical, and crystal-quality specifications.

Providing the intended application with your request can help identify whether a standard inventory wafer, custom substrate, epitaxial wafer, or lower-cost mechanical-grade option is appropriate.

How to Specify Silicon Carbide Wafers for a Quote

To help us identify an appropriate SiC substrate, include as much of the following information as possible:

• 4H-SiC, 6H-SiC, 3C-SiC, or required polytype
• Wafer diameter
• Thickness and tolerance
• N-type, semi-insulating, or other conductivity requirement
• Dopant
• Resistivity or carrier concentration
• Crystal orientation
• On-axis or off-axis requirement
• Si-face or C-face
• Single-side or double-side polish
• CMP or epi-ready surface requirements
• Surface roughness
• TTV, bow, and warp requirements
• Defect requirements
• Epitaxial-layer requirements, if applicable
• Quantity
• Intended research or device application

Related Silicon Carbide Resources

• 150mm Silicon Carbide Wafers
• 200mm Silicon Carbide Wafers
• Gallium Nitride Substrates
• MOSFET Research
• RF Semiconductor Research
• Microwave Photonics
• Silicon Wafers