Magnetron sputter epitaxy of wurtzite Al1-xInxN(0.1<x<0.9) by dual reactive dc magnetron sputter deposition

Ternary wurtzite Al1-xInxN thin films with compositions throughout the miscibility gap have been grown onto seed layers of TiN and ZrN by magnetron sputter epitaxy (MSE) using dual reactive direct current magnetron sputter deposition under ultra high vacuum conditions. The film compositions were calculated using Vegard's law from lattice parameters determined by x-ray diffraction (XRD). XRD showed that single-phase Al1-xInxN alloy films in the wurtzite structure with [0.10//TiN,ZrN<110>. At higher substrate temperatures almost pure AlN was formed. The microstructure of the films was also investigated by high-resolution electron microscopy. A columnar growth mode with epitaxial column widths from 10 to 200 nm was observed. Rocking curve full-width-at-half-maximum measurements revealed highly stressed lattices for growth onto TiN at 600 deg. C. Pseudobinary MSE growth phase field diagrams for Al1-xInxN onto ZrN and TiN were established for substrate temperatures up to 1000 deg. C. Large regimes for single-phase solid solutions were thus identified with In being the diffusing species