New Power Device Architectures in Silicon

Silicon has dominated the power semiconductor device market for the past 60 years and today still accounts for over 99%. Power devices are an enabling technology to many electrical systems and are becoming increasingly significant as low-carbon energy sources usurp traditional fossil fuels. Development of renewable energy such as wind and solar, transportation including trains and electric cars and the development of the UK "smart grid" network, to name but a few applications, would not be possible without a highly efficient power device. Therefore, research to understand the behaviour of current silicon power devices in order to improve performance is highly relevant to today's society. Over the past 20 years there have been many developments in silicon devices including the invention of the 3D reduced surface field effect (RESURF) which broke the perceived classical limit of silicon, the trench gate IGBT which overcame the constraint presented by planar IGBTs by enhancing the PiN diode effect and the use of lateral device structures in high voltage integrated circuits as an alternative to discrete devices due to increased reliability, efficiency and a reduction in overall size.

To build upon these developments, it is important that I first understand each power device in detail and this will form the initial stages of my PhD. Having narrowed my field to a particular application and device, I intend to develop accurate models in order to fully characterise the current device behaviour to enable further optimisation to occur. By employing some of the existing device concepts, I hope to design a new power device with improved performance and efficiency. Tests will be conducted using both simulation output and experimental data by manufacturing the device in silicon. It is hoped that, as a result of completing this research, the new design will contribute towards the ever growing need for efficient power devices across the wide breadth of industries.