Ammonothermal Bulk GaN Substrates for Power Electronics

摘要

Soraa has developed a novel ammonothermal approach for growth of high quality, true bulk GaN crystals at a greatly reduced cost, known as SCoRA (Scalable Compact Rapid Ammonothermal). SCoRA GaN growth has been performed on seed crystals with diameters between 5 mm and 2" to thicknesses of 0.5-4 mm. The highest growth rates are greater than 40 μm/h and rates in the 10-30 μm/h range are routinely observed. Two-inch diameter, crack-free, free-standing, n-type bulk GaN crystals have been grown. The crystals have been characterized by a range of techniques, including x-ray diffraction rocking-curve (XRC) analysis, optical microscopy, cathodoluminescence (CL), optical spectroscopy, and capacitance-voltage measurements. The crystallinity of the grown crystals is very good, with FWHM values of 15-80 arc-sec and average dislocation densities below 5× 10~5 cm~(-2).