Abstract: A wafer carrier includes a base including a generally planar bottom surface and a top surface that includes a plurality of platforms extending above the top surface. The wafer carrier includes a thermal cover defining a plurality of pockets. The thermal cover is configured to be coupled to the base by at least one fastener and the plurality of pockets are arranged such that each pocket of the plurality of pockets is aligned with a corresponding platform of the plurality of the platforms when the thermal cover is supported by a plurality of first pedestals that extend from the top surface of the base. A plurality of second pedestals are located along the plurality of platforms for supporting the one or more wafers, wherein each platform includes at least one second pedestal that extends from a top surface of the platform for supporting one wafer.

Abstract: In a method for making a low-defect single-crystal GaN film, an epitaxial nitride layer is deposited on a substrate. A first GaN layer is grown on the epitaxial nitride layer by HVPE under a growth condition that promotes the formation of pits, wherein after growing the first GaN layer the GaN film surface morphology is rough and pitted. A second GaN layer is grown on the first GaN layer to form a GaN film on the substrate. The second GaN layer is grown by HVPE under a growth condition that promotes filling of the pits, and after growing the second GaN layer the GaN film surface morphology is essentially pit-free. A GaN film having a characteristic dimension of about 2 inches or greater, and a thickness normal ranging from approximately 10 to approximately 250 microns, includes a pit-free surface, the threading dislocation density being less than 1×108 cm?2.

Abstract: In a method for making an inclusion-free uniformly semi-insulating GaN crystal, an epitaxial nitride layer is deposited on a substrate. A 3D nucleation GaN layer is grown on the epitaxial nitride layer by HVPE under a substantially 3D growth mode, wherein a surface of the nucleation layer is substantially covered with pits and the aspect ratio of the pits is essentially the same. A GaN transitional layer is grown on the nucleation layer by HVPE under a condition that changes the growth mode from the substantially 3D growth mode to a substantially 2D growth mode. After growing the transitional layer, a surface of the transitional layer is substantially pit-free. A bulk GaN layer is grown on the transitional layer by HVPE. After growing the bulk layer, a surface of the bulk layer is smooth and substantially pit-free. The GaN is doped with a transition metal during at least one of the foregoing GaN growth steps.