ECE alumnus Shen shares III-Nitride power electronics research at MNTL

Students, faculty, and staff gathered at MNTL the morning of Monday, June 27, to hear Professor Shyh-Chiang Shen (PhD ’01), visiting from the Georgia Institute of Technology, discuss III-Nitride Power Electronics. The ECE ILLINOIS alumnus currently conducts research at the Center for Compound Semiconductors (CCS), which is led by fellow alumnus Russell Dupuis (PhD ’73, MS ’71, BSEE ’70).

In his presentation, Shen explained that silicon has become a favored substrate, but new research demonstrates the advantages of using Gallium Nitride (GaN) for next generation high power and high speed applications.

Shen highlighted five characteristics that demonstrate the advantages of GaN compared to silicon power devices. Specifically, GaN offers higher dielectric strength, higher operating temperature, higher current density, higher speed switching, and lower on-resistance. The properties of GaN result in ten times higher electrical breakdown characteristics, three times the bandgap, and exceptional carrier mobility compared to silicon.

As a case study, Shen discussed applications in electronic vehicles. A silicon insulated-gate bipolar transistor (IGBT) requires significant cooling. However, GaN devices have a higher temperature advantage, eliminating the need for additional cooling and reducing the volume of the semiconductor by roughly 80 percent, dowsizing the associated sub-assembly for the motor drive. 

Shen also shared some of the current research challenges, including the fabrication process, which has been troubled by dry etching damage and a lack of wet etching uniformity. His group has developed a very promising proprietary electrode-less photon-enhanced wet-chemical surface treatment that creates a smoother surface with reduced leakage.

Shen expressed his deep gratitude to Milton Feng, who attended the presentation, for his seminal work leading to much of Shen's research.