| 摘要 |
<p>A method for fabricating gallium nitride on different substrates 3, comprising forming an AlGaN transition layer over the substrate, this layer has a graded composition such that the amount of aluminium decreases by a mathematical function with profile that has two plateaux, then forming a gallium nitride layer on top. It can also have a superlattice structure of at least two layers formed on the substrate in which the second layer has a greater thickness and lower Al composition than the first. A gallium nitride material can then be formed on the superlattice structure. The aluminium content of the layers in the superlattice can formed such that there is an Al compositional gradient throughout the superlattice transition layer. There can be just a single transition layer in which a layer of GaN is then formed on top before a subsequent transition layer is formed on top of that, with a further gallium nitride layer in this. The substrate wafer material can be laser treated to create an etching pattern located within the wafer. The device can have two transition layers formed at different temperatures.</p> |
