High-Voltage AlN MESFET on Single-Crystal AlN Substrates

Ultrawide bandgap materials (UWGP) like Ga₂O₃, diamond, and aluminum nitride (AlN) are promising for next generation high voltage, high temperature electronics due to their superior properties. AlN with its wide 6.2 eV bandgap and high 12 MV/cm breakdown field, is particularly attractive for high power applications. However, its development is hindered by high defect densities in layers grown on mismatched substrates like sapphire, leading to poor device performance, low carrier concentrations, and difficulty forming ohmic contacts. Additionally, the need for complex structures such as graded contact layers increase fabrication cost and reduces device reliability.

 

Researchers at Arizona State University have developed a high-voltage aluminum nitride (AlN) metal-semiconductor field-effect transistor (MESFET) fabricated on single-crystal AlN substrates, representing a significant advancement in UWBG semiconductor technology. This invention achieves low defect density, enabling superior device performance compared to traditional AlN devices grown on foreign substrates like sapphire. The MESFETs demonstrate a high breakdown voltage exceeding 2 kV, improved on/off current ratio, and enhanced thermal stability, making them ideal for high-power and high-temperature applications. Fabricated using metal-organic chemical vapor deposition (MOCVD) and conventional photolithography, these MESFETs maintain stable performance at elevated temperatures, demonstrating potential for high-voltage power applications. Further, the fabrication process, which eliminates the need for complex graded or regrown contact layers, reduces manufacturing costs and enhances device yield.

 

This technology provides for advanced AlN MESFETs on native substrates enabling high-voltage, high-performance power devices with superior electrical characteristics.

 

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