Process for producing an epitalixal layer of galium nitride

A method of manufacturing a low defect density GaN material comprising at least two step for growing epitaxial layers of GaN with differences in growing conditions,

• a. a first step of growing an epitaxial layer GaN on an epitaxially competent layer under first growing conditions selected to induce island features formation, followed by
• b. a second step of growing an epitaxial layer of GaN under second growing conditions selected to enhance lateral growth until coalescence, wherein Mg is added to a vapor phase of the second growing conditions.