Relationship Between the Rate of Photochemical Metal-Assisted Etching of GaN Layers and Multifractal Parameters of Their Surface Structure

The results of a study of liquid photochemical metal-assisted etching of a series of samples of n-type Ga-polar GaN layers grown by molecular-beam epitaxy with nitrogen plasma activation are presented. Under the chosen conditions of the etching process, it is shown that the etching rate depends mainly on the structural properties of the GaN layers, which manifest themselves in the surface morphology, which can be quantitatively characterized by the multifractal parameters Δq (the degree of ordering and symmetry breaking of the structure under study) and Dq (the Rényi dimension, which depends on the thermodynamic formation conditions). A correlation between the values of the multifractal parameters Δq and Dq of the surface structure and the etching rate of Ga-polar GaN layers is established.