For the economic as well as the ecological future of Europe energy savings and management are ground challenges. It is important to distribute and use electric energy in the most efficient manner. Thus, power transistors based on wide band gap (WBG) materials such as gallium nitride (GaN) and silicon carbide (SiC) are essential to enhance efficiency in power electronics by replacing conventional silicon (Si)-based technologies in power switches for a variety of applications and markets, such as electric vehicles, power supplies, industrial drives for e-motors or photovoltaic inverters.
However, existing lateral GaN power transistors are limited in their power handling capability while vertical SiC transistors are significantly more expensive than their Si-based counterparts. To that end, 23 European partners from research to industry joined their semiconductor and power electronics expertise in YESvGaN for an ambitious goal: to establish a new class of GaN power transistors, which combines the efficiency of WBG semiconductors with the cost benefits of Si technology. For this, innovative vertical transistor architectures using heteroepitaxial GaN layers on low-cost substrates were developed with advancements along the whole value chain, which are addressed by the following project objectives:
- Development of vertical drift epitaxy up to 1200 V blocking voltage on low-cost silicon or sapphire substrates up to 300 mm wafer size
- Development of low-cost, vertical GaN (vGaN) power transistors and process technology with performance above state-of-the-art SiC MOSFETs at chip costs competitive with Si IGBTs
- Development of membrane process technology for vGaN power transistors with ultra-low resistance contribution from the backside contact
- Development of advanced interconnection technology compatible with membrane vGaN power transistors and evaluation of their reliability based on ECPE Guideline AQG324
- Understanding performance limitations, degradation and failure mechanisms of membrane vGaN power transistors from chip to device
- Delivery of a datasheet for membrane vGaN power transistors with static and dynamic behaviour. Improvement of system efficiency by reducing losses up to 50% and by increasing power density by 15% (compared to silicon) for the chosen technology demonstrators of high-power converters in order to increase their cost efficiency.
