Oxford Instruments, a leading provider of high technology products and services for research and industry has joined hands with Hitachi Energy Switzerland, a global technology leader in sustainable energy and the University of Warwick to improve SiC power MOSFET gate technology through the use of ALD oxides.

This is one of 26 new projects intended to enhance UK and Swiss collaboration on innovation and technology, supported by £7.8 million funding from Innovate UK and a similar figure from Innosuisse, the Swiss innovation agency.

Hitachi Energy Switzerland (Hitachi) has a proven track record of developing automotive grade SiC power MOSFETs with a reputation for products with novel MOS interfaces.

Oxford Instruments Plasma Technology (OIPT) has developed a novel oxide deposition process that uses a remote plasma source in a commercial atomic layer deposition (ALD) system. This process is suitable for the formation of gate oxides in wide bandgap semiconductors.

A research team at the University of Warwick (UoW) has recently developed an ALD SiO₂ deposition process on SiC that has the potential to be commercialized. This project will bring together the three groups and their relative expertise to demonstrate the potential of ALD oxides in the formation of EV-grade 1.2 kV SiC MOSFETs.

The aim is to address one of the most pressing issues in the adaptation of this technique by fundamentally changing the way of forming a crucial part of the device, the gate oxide. Conventional dielectric and SiC interfaces are suffering from high density of defect states, hampering the further uptake of this technology.

This proof-of-concept project will demonstrate the viability and advantages of utilizing ALD-deposited oxides (SiO₂ and high-k dielectrics such as aluminum oxide, Al₂O₃ in a commercial SiC MOSFET device.

Key outputs

• The first demonstration of a commercially relevant planar 1.2 kV SiC MOSFET that contains OIPT’s remote plasma ALD-deposited silicon dioxide (SiO₂) and high-k dielectric (for example Al₂O₃) gate oxides
• A demonstration of the excellent interface quality (for example high channel mobilities due to the low density of interface traps) in these structures through the extraction of key performance indicators such as specific on-resistance or channel mobilities
• Demonstration of process benefits by benchmarking with existing commercial products
• Long-term reliability testing on the demonstrator MOSFETs will demonstrate whether the ALD oxides remain stable over the lifetime of a commercial automotive semiconductor product
• Integration of the novel ALD oxidation process into a research-grade trench MOS capacitor and trench MOSFET structure