AlGaN/GaN micromembranes with diamond coating for high electron mobility transistors operated at high temperatures

In this work, we present an application of NCD layers as backside cooling for AlGaN/GaN heterostructures grown on Si substrates. In this case, diamond nucleation is the most limiting technological step due to low mechanical stability of GaN membranes. We observed that standard nucleation techniques (ultrasonic seeding or bias enhanced nucleation) caused cracking of the membranes or not appropriate nucleation efficiency in the Z-depth of structures. Therefore we implemented PVA polymer consisting of diamond powder as seeding composite which resulted in a successful growth of diamond thin film.