With the rapid advancement of third-generation semiconductor technologies, Silicon Carbide (SiC) has emerged as a key material due to its wide bandgap, high thermal conductivity, high breakdown electric field, and excellent chemical stability. These properties make SiC an ideal choice for extreme environments involving high voltage, high frequency, and high temperature. One of the most important parameters that determine SiC substrate performance is doping type. This article provides an in-depth overview of common doping methods and their application scenarios, serving as a guide for device design and material selection.

What is Doping?

Doping refers to the intentional introduction of trace impurities into the semiconductor crystal during growth to regulate its conductivity and resistivity. By doping, SiC materials can be tailored to exhibit N-type or P-type conductivity, or to become semi-insulating, depending on the electrical requirements of the device.

Common Doping Types and Characteristics

1. N-type SiC

Doping elements: Nitrogen (N) or Phosphorus (P)

Conductivity: Electrons as majority carriers

Resistivity: Typically 0.015–0.03 Ω·cm (for 4H-SiC)

Features: High conductivity and electron mobility; ideal for high-frequency, high-voltage power devices

Applications: SiC MOSFETs, Schottky Barrier Diodes (SBD), IGBTs, JFETs

N-type SiC is created by doping with nitrogen or phosphorus to generate free electrons. Its high conductivity and low resistivity make it ideal for power electronic components requiring fast switching and high efficiency.

2. P-type SiC

Doping elements: Aluminum (Al) or Boron (B)

Conductivity: Holes as majority carriers

Resistivity: Varies with doping concentration

Features: Lower hole mobility than electrons; typically used in epitaxial layers

Applications: P-N junctions, P-type epitaxial structures, high-temperature electronics

P-type SiC is doped with aluminum or boron to create hole carriers. It is crucial for forming P-N junctions and is commonly used in high-temperature and complementary device structures.

3. Semi-insulating SiC

Doping elements: Vanadium (V) or defect engineering

Conductivity: Very high resistivity (>10⁶ Ω·cm)

Features: Suppresses free carrier concentration; offers excellent electrical isolation

Applications: RF devices, microwave power amplifiers, isolation layers

Semi-insulating SiC is achieved by doping with vanadium or by controlling intrinsic defects to reduce conductivity. These substrates provide the electrical isolation needed in high-frequency and RF applications.

4. Undoped SiC

Doping elements: None (pure crystal growth)

Conductivity: May exhibit weak conductivity depending on impurities

Features: Suitable for research and high-temperature sensing

Applications: R&D, high-temperature sensors, custom epitaxial structure development

Undoped SiC is grown without intentional doping, offering a neutral electrical baseline. It's useful in specialized applications like high-temperature sensing and material studies.

Application Reference Table

Selection Guide & JXT Technical Support

When choosing a SiC substrate, it is essential to evaluate the electrical requirements of the end device, including voltage levels, frequency response, and thermal management. High-power applications often favor N-type conductive substrates, while RF and communication fields typically require semi-insulating materials.

JXT Technology offers high-quality SiC substrates ranging from 2 to 8 inches, with customizable doping types, resistivity levels, crystal orientations (4H/6H), and thicknesses. Our experienced technical team supports material selection, technical consultation, and sample testing to assist you in developing next-generation high-performance devices.