Reader in Power Electronic Devices
MEng, PhD (Warwick), SMIEEE, MIET, SFHEA
For the past ten years, I have worked on the development of silicon carbide (SiC) power devices. After working on SiC heterojunction devices during my PhD, I held a 5-year Royal Academy of Engineering Research Fellowship developing silicon-on-silicon carbide (Si/SiC) power devices for the harsh environment from 2012-2017. These devices continue to be developed with the aim of producing radiation tolerant Si/SiC devices for space applications.
I am also very interested in the development of high voltage SiC devices for applications from the grid and future HVDC implementations, to traction and renewables. Now a member of the EPSRC Centre for Power Electronics National Executive, I lead the 2018 Switch Optimisation theme (EP/R00448X/1), in which a consortium of Warwick, Coventry, Cambridge and Newcastle Universities, are attempting to be one of the first groups in Europe to develop and research SiC IGBTs.
I retain a great interest into the development and characterisation SiC Schottky diodes, a subject I have written a number of papers on. The Trasica Project, funded by Innovate UK and in partnership with Dynex Semiconductor and Cambridge Microelectronics, we are currently developing 3.3 kV SiC junction barrier Schottky diodes for a European traction application.
Underpinning Power Electronics (UPE) 2: Switch Optimisation Theme
Silicon carbide (SiC) N-channel IGBTs have the potential to enable new and highly efficient ultrahigh voltage (10 kV+) applications such as the Smart Grid and HVDC, enabling a low carbon society. An absence of P+ SiC substrates makes the SiC IGBT one of the most challenging devices to fabricate. The aim of the project is to be among the first groups in Europe to develop these devices, and to push the boundaries of what has been achieved in this fledgling field to date. Once a quality benchmarked ~10 kV SiC IGBT process is developed as the first milestone in this project, the process will be modified to explore areas not to-date explored. These include the development of lower voltage (5 kV) SiC IGBTs benchmarked to SiC MOSFETs, higher voltage (20 kV+) SiC IGBTs, and novel topologies such as SiC trench IGBTs, hybrid SiC MOSFET-IGBTs and SiC Superjunction devices.
|Si/SiC Power Device Research
My team are developing a range of power electronic devices that can work in the harsh environment, including space. These use a novel combination of silicon on silicon carbide (Si/SiC) to exploit the advantages of each of the semiconductors. A thin film of silicon is a reliable and highly efficient device layer for electronics at medium voltages (<600V). Meanwhile, the SiC helps to manage self-heating, its high thermal conductivity efficiently removing the heat from the silicon enabling efficient device performance.
I have worked extensively in other research fields including SiC and GaN power electronics, on the modelling of metal/semiconductor Schottky diodes and on energy harvesting techniques using rectennas devices.
My work on modelling Schottky diodes has helped to explain curious effects, 'inhomogeneities', witnessed in the turn-on characteristics of these devices, such as decreasing ideality factor, increasing barrier height and, in particularly extensive double bumps in the log(I)-V plots. My 2013 Journal of Applied Physics paper describes how the best known theory into metal-semiconductor inhomogeneity can be developed into a technique that can model real experimental data, so establishing a method to quantify the homogeneity of a diode.
In collaboration with Imperial College, work was carried out on another rectenna application, this time for solar energy harvesting. Based on a scaled-down version of your radio or T.V. antenna, nano-scaled gold antennae couple with the infra-red, or visual spectrum setting up a small electric field across the metal-semiconductor interface. Our work in this area was published in the first ever article to appear in the journal MRS Energy & Sustainability: A Review Journal.
The Engineering Department at the University of Warwick is renowned for its research activity into SiC Power devices. With a unique clean room facility dedicated to SiC power device fabrication, significant research effort is being invested into bringing these high power density, high frequency and high temperature devices to market. I have an interest in SiC Schottky and PiN diodes, characterising Fermi-level pinning, and temperature-based effects. I am also interedsted in characterising SiC MOSFETS and other devices at cryogenic temperatures down below 20K.
10/01/2020: JAP paper published on ultra-low leakage molybdenum-SiC Schottky diode process.
01/08/2019: ECSCRM 2018 Proceedings published
01/12/2018: The PEATER Research Group is named University Research Group of the Year 2018 at the TechWorks Awards ceremony.
07/09/2018: ECSCRM 2018 concludes successfully. The leading SiC conference was organised by the Warwick PEATER team.
The Research Team
(The people who do the actual work)
Dr Tianxiang Dai (EPSRC, SiC IGBT Development)
Dr Oliver Vavasour (SiC Devices and Characterisation)
Guy Baker (SiC Power Devices)
Arne Benjamin Renz (SiC Materials/Devices)
Naiwu Yuan (SiC Applications)
Luyang Zhang (SiC Device Modelling)
Yunyi Qi (SiC Rad-hard Device Modelling)
MSc by Research:
Han Chen (SiC Cryogenic Performance)
Dr Chunwa Chan (Si/SiC Power Devcies)
Dr Oliver Vavasour (III-V devices)
Yegi Bonyadi (SiC Power Devices)
GaN Power Electronics: