Seminar & Colloquium
[세미나: 12월 26일(월), 오전 10시 30분] Osaka University, 길태현 교수
Title
Study on the band alignment change of 4H-SiC gate stack induced by interface nitridation and gate stack formation processes
Speaker
Osaka University, Assistant Professor, 길태현 교수
Education
- 2018.9 - 2021.9 University of Tokyo, Tokyo, Japan
Ph.D. in Materials Engineering
Advisor: Assoc. Prof. Koji Kita
- 2015.9 - 2018.8 Seoul National University, Seoul, South Korea
M.Sc. in Materials Science and Engineering (GPA: 3.62/4.30)
Advisor: Prof. Chan Park
- 2009.3 - 2015.8 Seoul National University, Seoul, South Korea
B.Sc. in Materials Science and Engineering (GPA: 3.19/4.30)
Professional Experience
- 2021.10 - 현재 Assistant Professor, Osaka University, Osaka, Japan
- 2018.9 - 2021.9 Ph.D. candidate, The University of Tokyo (UT), Tokyo, Japan
- 2015.9 - 2018.8 Research Assistant, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| Date | Monday, December 26th, 2022
| Time | 10:30 ~ 11:30
| Venue | 33동 230호
[Abstract]
Silicon carbide (SiC), owing to its high breakdown electric field and high thermal conductivity, is one of the promising wide band-gap semiconductors for power electronics. However, even though it has high bulk electron mobility, 4H-SiC MOSFETs show low channel mobility because of the poor SiO2/4H-SiC interface quality. For the improvement of interface quality, the nitridation process is a well-known technique. One of the drawbacks of interface nitridation is a significant flat-band voltage or threshold voltage shift to the negative direction. From the viewpoint of industrial applications, the control of threshold voltage is very crucial for power device operation and its reliability.
In this work, we found that the unexpected shift of flat-band voltage is related to the band alignment change, induced by the formation of a dipole layer at the SiO2/SiC interface after nitridation. To recover negatively shifted flat-band voltage or threshold voltage, we adopted an additional dielectric layer, Al2O3 on SiO2/SiC. Owing to the formation of an additional dipole layer, we could demonstrate the positive shift of threshold voltage, while maintaining the field-effect mobility of MOSFET.
| Host | 박찬 교수 (02-880-9324)