£1.3M project award to UK GaN power consortium
GaNTT project will develop a voltage-scalable, vertical GaN process platform suitable for electric vehicle applications
A consortium led by the Compound Semiconductor Centre (CSC) has been awarded funding through ‘The road to zero emission vehicles’ competition sponsored by OLEV (the Office for Low Emission Vehicles). CSC leads a consortium of partners across the power electronics supply chain: SPTS Technologies, Newport Wafer Fab, Turbo Power Systems Ltd and the Compound Semiconductor Applications (CSA) Catapult, supplemented with academic expertise in power systems and devices; Swansea University and Coventry University.
The GaNTT (Realisation of a mass-manufacturable Vertical GaN Trench FET architecture) project will develop a voltage-scalable, vertical GaN process platform (200V - 600V) suitable for electric vehicle applications and integrate the resulting device into an on-vehicle demonstrator for bi-directional battery charging. Vertical GaN architectures are a viable future technology for low to medium voltage and power applications e.g. On Board Charging (OBC) and DC-DC applications where higher switching speed is desirable. It also has the potential to meet the cost challenges related to current SiC FET technologies, though significant challenges in epitaxial material layer quality and device thermal management require de-risking.
The project will focus on development of large diameter substrate solutions that provide high quality, thick GaN layers and address the challenges of lattice mismatch and wafer bow by employing novel epitaxial substrate solutions for future foundry products. Vertical GaN devices architectures enable FET operation at high electric fields and thus facilitates a significant reduction in chip area compared to lateral power devices. The breakdown voltage can be increased by increasing the thickness of the epitaxial drift region supporting the electric field enabling the voltage to be scaled independently of chip area. The device approach also incorporates an innovative Source-metal/P-body Schottky contact approach, patented by researchers from Swansea and Coventry Universities, to provide better control and stability of the channel threshold voltage.
Crucially, this project will evaluate prototype devices at packaged device and sub-system level, with Turbo Power Systems providing a Tier 1 automotive testing environment. The activity will establish a ‘materials to system’ UK supply chain in wide band gap materials and enhances exploitation opportunities for all partners by ensuring that device development is driven by automotive requirements. The performance benefits of this new platform technology are not limited to automotive applications, but are also highly suitable for use in other harsh environments, eg Space applications where the combination of improved power density and radiation-hardness would reduce payload and improve system reliability.
Robert Harper, GaN Programme Manager at CSC commented: “Vertical GaN Power Technology will deliver emerging opportunities across a broad applications space, currently growing at >50% CAGR and forecast to be worth >$150-300M by 2023. This activity will build on UK strengths in compound semiconductor materials and device technology to energise a new supply chain in automotive power component supply”.
