The progress of AlN bulk growth and epitaxy for electronic applications

We report on the progress of high quality AlN bulk crystal growth by the sublimation‐recondensation technique and present a theoretical model for optimizing the growth conditions. The theoretical model is consistent with our experimental findings and projects a path to maximize the growth rate by adjusting the growth temperature, external nitrogen pressure and source‐to‐seed distance. The growth of large AlN boules has resulted in the demonstration of crack‐free AlN wafers up to 2‐inch diameter. The crystallinity of these AlN boules and wafers has been characterized by X‐ray techniques and etch pit density (EPD) measurements. The AlN wafers exhibited X‐ray rocking curves with a full width at half maximum (FWHM) close to 30 arcsec for both symmetric and asymmetric curves with a corresponding EPD of