Among third-generation semiconductor materials, silicon carbide (SiC) has become a core material for high-voltage and high-power electronic devices due to its excellent electrical, thermal, and mechanical properties. Currently, Chemical Vapor Deposition (CVD) is the most widely used and mature technique for SiC epitaxial wafer fabrication. This article provides a systematic overview of mainstream SiC epitaxial growth methods, a technical comparison of different processes, and future development trends.
 

1. Importance of Epitaxial Growth in SiC Devices

 
In SiC power device manufacturing, nearly all process steps are based on 4H-SiC homoepitaxial layers. The substrate primarily serves as mechanical support and a conduction pathway. The epitaxial layer must be precisely engineered in terms of thickness, doping concentration, and doping type (N-type or P-type) to meet the specific requirements of devices such as MOSFETs, Schottky barrier diodes (SBDs), and junction barrier Schottky (JBS) diodes.
 

Currently, the primary techniques for growing SiC epitaxial layers include:

Chemical Vapor Deposition (CVD)
Molecular Beam Epitaxy (MBE)
Liquid Phase Epitaxy (LPE)
Pulsed Laser Deposition (PLD)
 
Among these, CVD stands out as the dominant choice for industrial-scale production due to its superior process controllability and scalability.
 

2. Chemical Vapor Deposition (CVD) Technology

 
CVD is the mainstream method for 4H-SiC epitaxial growth. In this process, at elevated temperatures (typically 1500–1650°C), silicon-containing gases (e.g., SiH₄, SiCl₄, or MTS) and carbon sources (e.g., propane C₃H₈) react in a hydrogen atmosphere to deposit high-quality single-crystal SiC layers on a substrate.
 

Key Advantages of CVD:

   • Excellent process controllability: Gas flow rates, temperature, and pressure can be precisely tuned.
   • Flexible doping control: Enables both N-type and P-type doping with accurate concentration management.
   • Accurate thickness control: Allows precise growth from a few microns to hundreds of microns.
   • High maturity of equipment and process: Well suited for mass production.
   • Lower operation and maintenance costs: Compared to ultra-high vacuum systems.
 

 

3. Comparison of SiC Epitaxial Growth Methods

While CVD is the mainstream industrial method, other techniques are still relevant in specific research or niche applications. The table below summarizes the key characteristics of several common epitaxial growth methods:
 

Epitaxial Method	Advantages	Disadvantages	Growth Rate	Industrial Suitability
CVD	Mature process, high precision, supports thick films	High equipment cost, high-temperature requirements	5–50 µm/h (adjustable)	Mainstream industrial use
MBE	Lowest defect density, excellent crystal quality	High cost, slow growth rate, not scalable	<1 µm/h	Mainly for research
LPE	Simple setup, low cost	Poor doping uniformity, limited thickness control	1–5 µm/h	Largely phased out
PLD	Flexible material compatibility	Limited uniformity, size constraints	<1 µm/h	Laboratory-scale use

 

4. Future Development Trends

4.1 Transition to Larger Wafer Sizes

Driven by growing demand from electric vehicles and industrial sectors, the SiC wafer size is shifting from 150 mm to 200 mm. This transition imposes stricter requirements on epitaxy equipment in terms of temperature uniformity, thickness homogeneity, and doping precision.
 

4.2 Defect Density Reduction

Future CVD technologies will focus on:
Suppressing basal plane dislocations (BPDs)
Reducing stacking faults (SFs) and micropipes
Optimizing off-axis substrate angles and growth conditions

4.3 High-Efficiency, Low-Energy Growth Processes

The development of low-temperature, high-rate CVD variants (e.g., chlorinated CVD) will be essential for increasing throughput and reducing cost while maintaining high epitaxial quality.
 

5. Conclusion

Among all SiC epitaxial growth technologies, Chemical Vapor Deposition (CVD) offers the best combination of high growth rates, excellent crystal quality, strong process control, and industrial scalability, making it the dominant choice for SiC wafer production
While methods such as MBE and LPE may still be useful in research or specific applications, CVD is currently the most competitive and commercially viable solution. As the industry continues to demand larger wafers, thicker epitaxial layers, and higher device performance, CVD will evolve to meet these needs and will play an increasingly vital role in the SiC power electronics ecosystem.