Growth of III-Nitride films on mismatched substrates without conventional low temperature nucleation layers

摘要

A method of forming a light emitting device includes providing a sapphire substrate, growing an Al 1-x Ga x N first layer by vapor deposition on the substrate at a temperature between about 1000°C and about 1180°C, and growing a III-nitride second layer overlying the first layer. The first layer may have a thickness between about 500 angstroms and about 5000 angstroms. In some embodiments, reaction between the group V precursor and the substrate is reduced by starting with a low molar ratio of group V precursor to group III precursor, then increasing the ratio during growth of the first layer, or by using nitrogen as an ambient gas.