Interfacial adhesion strength of III-N heterostructures

Wide bandgap semiconductors such as group III-nitrides and SiC are considered key materials for the fabrication of smaller, more reliable efficient power electronics. Fabrication robust durable devices requires an optimized design based on understanding interfacial adhesion properties constituent thin-film heterostructures. In this study, GaN/AlN layers grown Si substrates were investigated. Particularly, influence AlN buffer layers, necessary GaN growth Si, delamination response was determined. The strength obtained using cross-sectional nanoindentation (CSN) four-point bending (4PB) tests. Analytical models beam- elastic plate theory which applied respectively to calculate fracture energy (Gic) both methods found be in good agreement provided loading conditions similar. Detailed transmission scanning electron microscopy investigations prior subsequent reveal microstructural details relevant interfaces provide insights into encountered mechanisms failure. Finally, probability along weakest interface is discussed a mechanics model.