Highly Scaled III-N HEMTs
GaN-based III-N high electron mobility transistors (HEMTs) have shown considerable improvements in performance in the last two decades. The inherent material properties such as high breakdown field, high mobility and saturation velocity, high thermal conductivity, and wide bandgap make III-N HEMTs a promising candidate for many microwave power and low-noise applications. The combination of improved epitaxy and fabrication techniques has enabled devices to obtain outstanding output power performance, unity current gain cutoff frequency, and maximum frequency of oscillation.
There have been considerable efforts to scale dimensions in III-N HEMTs to improve high-frequency performance of transistors. At the Ohio State University, we are investigating the characteristics and performance of various band-engineered and polarization-engineered GaN-based HEMT structures. Based on the optical phonon scattering effect in GaN HEMTs, we study a new concepts of highly scaled multiple channel heterostructures with high effective electron velocity, high transconductance, and high gate-to-source capacitance. In addition, we are investigating the origin of short-channel effects and the new technology for reducing short-channel effects in FETs structure using TCAD simulations.
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3) Park, Pil Sung, Digbijoy N. Nath, and Siddharth Rajan. "Quantum capacitance in N-polar GaN/AlGaN/GaN heterostructures." Electron Device Letters, IEEE33.7 (2012): 991-993.
4) Park, Pil Sung, et al. "Electron gas dimensionality engineering in AlGaN/GaN high electron mobility transistors using polarization." Applied Physics Letters100.6 (2012): 063507.