MEng, PhD (Warwick), MIET, MIEEE, FHEA
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. Work continues via H2020 and EPSRC grants I lead towards 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 will lead the 2018 Switch Optimisation theme, in which a consortium of Warwick, Coventry, Cambridge and Newcastle Universities, will attempt 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 numebr 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.
|My team are developing a range of power electronic devices that can work in the harsh environment. 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 am principal investigator on two current projects that look to develop Si/SiC solutions:
SaSHa is the largest ever Si/SiC project and will begin in February 2016, funded for two years by the EU’s Horizon 2020 programme. 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.
Beginning November 2015, this £125k EPSRC will for two years look to develop Si/SiC power devices for downhole applications with project partners Halliburton and TT Electronics. With a temperature gradient beneath the surface of around 25°C/km, the ambient conditions can exceed 225°C in the deepest wells, while coping at the same time with extreme vibration, pressure, and corrosive liquids and gases. Maintaining reliability in this environment is a significant challenge, especially given the often quoted figure for downtime on an offshore rig being more than $1M per day to the drilling company.
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.
Fan Li (H2020, SaSHa, Si/SiC Devices)
Chunwa Chan (EPSRC, Si/SiC Devices)
Yegi Bonyadi (Innovate UK, Trasica, SiC Diodes)
Chunwa Chan (Si/SiC Power Devcies)
Yegi Bonyadi (SiC Power Devices)
Oliver Vavasour (Dielectrics for III-V devices)
Guy Baker (SiC Power Devices)
Arne Benjamin Renz (SiC Materials/Devices)
MSc by Research:
Naiwu Yuan (SiC Applications)
MSc by Research:
Han Chen (SiC Cryogenic Performance)
GaN Power Electronics: