Fabrication of freestanding GaN microstructures using AIN sacrificial layers

The fabrication of freestanding GaN microstructures using AlN sacrificial layers (SLs) is reported. GaN layers were grown by plasma assisted molecular beam epitaxy (PAMBE) on polycrystalline AlN sacrificial layers that have been deposited at 600 °C. Isotropic wet chemical etching of the AlN film released GaN microbridges and - cantilevers. The stress gradient and the compressive stress in the GaN-film was extracted by analysis of the relation between beam geometry and displacement.