B.Eng, M.Sc, PhD
School of Engineering
University of Warwick
CV4 7AL, UK.
Tel: +44 (0) 2476 551621
Email: F dot Li dot 3 at warwick dot ac dot uk
- Design and fabrication of power electronic semiconductor devices- MOSFET, Schottky diode, IGBT.
- Novel electronic materials chaterisation such as 4H-SiC, Ga2O3, 3C-SiC on Si, Si/SiC direct bonding.
- Feb 2018 - Now
Silicon carbide presents a high breakdown field (2-4 MV/cm) and a high energy band gap (2.3–3.2 eV), largely higher than for silicon. Within this frame, the cubic polytype of SiC (3C-SiC) is the only one that can be grown on a host substrate with the huge opportunity to grow only the silicon carbide thickness required for the targeted application. Even the relatively narrow band-gap of 3C-SiC (2.3 eV), which is often regarded as detrimental in comparison with other polytypes, can in fact be an advantage. The lowering of the conduction band minimum brings about a reduced density of states at the SiO2/3C-SiC interface and MOSFET on 3C-SiC has demonstrated the highest channel mobility of above 300 cm2/V.s ever achieved on SiC crystals, prompting a remarkable reduction in the power consumption of these power switching devices.
In this project (http://www.h2020challenge.eu/) new approaches for the reduction of defects will be used, working on new compliance substrates that can help to reduce the stress and the defect density at the same time. This growth process will be driven by numerical simulations of the growth and simulations of the stress reduction. The structure of the final devices will be simulated using the appropriated numerical tools where new numerical model will be introduced to take into account the properties of the new material. Thanks to these simulations tools and the new material with low defect density, several devices that can work at high power and with low power consumption will be realized inside the project.
- Oct 2016 - Jan 2018
Working on the SaSHa project (http://www.sashaproject.eu/) - Si on SiC for the Harsh Environment of Space: Funded by EU2020, Concentrating on the development of power electronics devices specifically for Space applications, the devices will be designed to withstand temperatures as high as 300°C and as low as -150°C, and in high radiation conditions. The consortium will be led at Warwick who will produce the Si/SiC devices in their unique cleanroom facility. UK SME, Cambridge Microelectronics, will carry out extensive simulations in order to optimise a design layout. The Tyndall Institute in Ireland will produce the novel wafer bonded Si/SiC material, while the Catholic University of Leuven (UCL) will carry out radiation modelling and testing. Thales Alenia Space UK will play a major role in shaping the characteristics of the devices.
- Oct 2012 - Sep 2016
My PhD research topic was about 3C-SiC semiconductor applications in medium power devices (MOSFETs, Schottky Diodes). It not only involves design and modelling of 3C-SiC on Si power device structures using TCAD software, but also fabricating and characterizing actual semiconductor devices using the clean room facility based in University of Warwick. During the 4 year period, most work was put into exploring the 3C-SiC/metal and 3C-SiC/SiO2 interfaces. Prototype 3C-SiC on Si LDMOSFETs were fabricated and characterised.
- F. Li, Q. Song, A. Pérez-Tomás, V. Shah, Y. Sharma, D. Hamilton, C. Fisher, P.M. Gammon, M.R. Jennings and Phil Mawby, "A first evaluation of thick oxide 3C-SiC MOS capacitors reliability," in IEEE Transactions on Electron Devices, vol. 67, no. 1, pp. 237-242, 2020.
- F. Li, V. Jokubavicius, M.R. Jennings, R. Yakimova, A. Pérez-Tomás, S.A.O. Russel, Y. Sharma, F. Roccaforte, P.A. Mawby, "Electrical characterisation of thick 3C-SiC layers grown on off-axis 4H-SiC substrates," Materials Science Forum, Vol. 963, pp. 353-356, 2019.
- F. Li, M.R. Jennings, Book chapter "Main differences in processing Si and SiC devices", Intech-open, "Disruptive wide bandgap semiconductors, related technologies, and their applications", Y.K. Sharma, pp. 45-64, 2018.
- F. Li, P.M. Gammon, C.W. Chan, F. Gity, T. Trajkovic, V. Kilchytska, V. Pathirana, K. Ben Ali, D. Flandre, P.A. Mawby, and J.W. Gardner, “Design and fabrication of a power Si/SiC LDMOSFET for high temperature applications”. HiTen2017, pp. 219-222, 2017.
- F. Li, O. Vavasour, M. Walker, D. Martin, Y. Sharma, S. Russell, M. Jennings, A. Pérez-Tomás, P. Mawby, "Physical characterisation of 3C-SiC(001)/SiO2 interface using XPS", Materials Science Forum, Vol. 897, pp. 151-154, 2017.
- F. Li, Y. Sharma, D. Walker, S. Hindmarsh, M. Jennings, D. Martin, C. Fisher, P. Gammon, A. Pérez-Tomás, "3C-SiC transistor with ohmic contacts defined at room temperature", IEEE Electron Device Letters, vol. 37, pp. 1189, 2016.
- F. Li, Y. Sharma, M. Jennings, A. Pérez-Tomás, V. Shah, H. Rong, S. Russell, D. Martin, P. Mawby, "Improved channel mobility by oxide nitridation for n-channel MOSFET on 3C-SiC (100)/Si", Materials Science Forum, Vol. 858, pp. 667-670, 2016.
- F. Li, Y. Sharma, V. Shah, M. Jennings, A. Pérez-Tomás, M. Myronov, C. Fisher, D. Leadley, P. Mawby, "Electrical activation of nitrogen heavily implanted 3C-SiC(1 0 0)", Applied Surface Science, vol. 353, pp. 958-963, 2015.
- F. Li, Y. Sharma, D. Hamilton, C. Fisher, M. Jennings, S. Burrows, P. Mawby, "Ohmic contact on n-type 3C-SiC activated with SiO2 encapsulation", Materials Science Forum, Vols. 821-823, pp. 395-398, 2015.
- F. Li, Y. Sharma, M. Jennings, H. Rong, C. Fisher, P. Mawby, "Study of a novel lateral RESURF 3C-SiC on Si Schottky diode" 16th European Conference on Power Electronics and Applications, 2014.