ABSTRACT
We investigated the possibilities of vapour phase epitaxy in an open tube chloride system for thick GaN film deposition on sapphire substrates. The methodes of the buffer layer deposition were proposed and developed. The method of fast (up to 100 microns / hour) was developed. Parameters of good quality gallium nitride epitaxial were obtained.
To determine the quality of fast grown epitaxial layers we used X-ray diffraction and photoluminescence measurements. Halfwidth of rocking curve for best samples w as equal to 4–6 minutes. Luminescense spectrum (T=77K) had a maximum near 3.46 eV. A signal in a visible wavelength range was hardly observed. Polished layers w¾re transparent.
A special initial treatment of the substrates allowed us to separate thick (up to 300 micron) epitaxial gallium nitride layers from sapphire. It was shown that it is possible to use separated films for homoepitaxy of GaN.
