SINGLE STEP PENDEO- AND LATERAL EPITAXIAL OVERGROWTH OF GROUP III-NITRIDE LAYERS

摘要

A method of fabricating a gallium nitride-based semiconductor structure on a substrate includes the steps of forming a mask (14) having at least one opening (6) therein directly on the substrate (18), growing a buffer layer (12) through the opening, and growing a layer of gallium nitride (20) upward ly from the buffer layer and laterally across the mask. During growth of the gallium nitride from the mask, the vertical and horizontal growth rates of t he gallium nitride layer are maintained at rates sufficient to prevent polycrystalline material (30) nucleating on said mask from interrupting the lateral growth of the gallium nitride layer. In an alternative embodiment, t he method includes forming at least one raised portion (15) defining adjacent trenches (18) in the substrate and forming a mask (14) on the substrate (10) , the mask having at least one opening (16) over the upper surface of the rais ed portion. A buffer layer (12) may be grown from the upper surface of the rais ed portion. The gallium nitride layer (26) is then grown laterally by pendeoepitaxy over the trenches.