Presentation Information
[8p-S102-4]N-polar GaN-Based Heterostructures: Challenges and Opportunities
〇Tetsuya Suemitsu1, Takeshi Kimura1, Takashi Matsuoka1 (1.Tohoku Univ.)
Keywords:
nitride semiconductor,polarization,field-effect transistor
GaN-based heterostructures have a unique property that is so called polarization doping effect. It makes GaN-based high electron mobility transistors (HEMTs) distinguished power devices for a wide frequency range, from kHz to GHz, because of their two-dimensional electron gas (2DEG) with high mobility and high sheet carrier concentration. Although almost all of GaN-based devices developed so far are made with a Ga-polar material system, i.e., wurtzite crystals grown in +c direction, N-polar nitride semiconductors grown in -c direction are paid growing attention since high-quality N-polar GaN was successfully realized by metal organic vapor phase epitaxy (MOVPE). After that, N-polar GaN HEMTs have been developed intensively for millimeter-wave power devices. Since N-polar GaN HEMTs consist of a GaN channel on the top and a AlGaN back barrier layer, they have an advantage to achieve strong 2DEG confinement in the top GaN channel, which is beneficial to mitigate the short channel effect in sub-0.1-µm gate HEMTs that are commonly used for millimeter-wave transistors.
In this talk, our results on N-polar GaN-based HEMTs and the studies on surface/interface polarization charge model to explain the barrier height of N-polar GaN are reviewed.
In this talk, our results on N-polar GaN-based HEMTs and the studies on surface/interface polarization charge model to explain the barrier height of N-polar GaN are reviewed.