photolithographic techniques e g for stripe formation as demonstrated in fig1 the mask dimensions provided through standard photolithographic techniques are sufficiently large such that when the lateral growth faces coalesce there is a high probability that crystal tilt and or twist can have occurred between the two merging crystal fronts resulting in a high density of defects at the point of merger between the lateral overgrown faces therefore when considering the example in fig1 employing striped mask geometries the surface defects are non randomly distributed over the surface of the epilayer resulting in areas with high levels of defect densities and areas with comparatively low levels of defect densities although this non random distribution of defects is satisfactory for certain device with particular geometries i e laser structures consisting of thin stripe geometries can avoid defected material wider area geometry devices such as transistors and light emitting diodes have a device area which could comprise both high and low quality material a mixture of both high and low quality material encompassed within a single device is detrimental to optimized device performance in contrast the methods of the invention produce a more advantageous defect distribution namely having a lower density of defects more randomly distributed over the surface of the iii nitride epilayer the present invention produces substrates favorable for elo growth and having island like structures of nitride material distributed without regular pattern that is distributed u201c randomly u201d or u201c substantially randomly u201d between which a discontinuous layer of silicon nitride material preferentially masks most or all exposed portions of the base substrate the islands preferably act as seeds for promoting subsequent elo and are not only randomly arranged but more.