Gallium Nitride: Past, Present and Future in an Ever-Changing Market

Gallium Nitride is a very exciting solution for many power electronics applications as the market continues to evolve and, in many ways, may emerge as even more important than Si and SiC. The primary reason remains its superior materials properties, most importantly the high mobility that is afforded by the AlGaN/GaN heterojunction. Lateral GaN power devices are attractive because the full region that holds voltage is a high electron mobility region and it is uniquely capable of delivering bidirectional voltage blocking when off and conduction when on, important in many applications including, solar inverters, chargers and motor drives. Lateral devices are also amenable to integrating smart functionality with the device. The drawback of a lateral device is a larger chip size and the need for field plates to manage fields, issues that can be mitigated with superjunction technology, now being demonstrated by multiple research institutions. Vertical GaN devices, on the other hand, are attractive for small chip-size and high-voltage rating, but have significantly lower electron mobility and require low dislocation density bulk substrates for reliable operation, which increases cost.