A new system for sodium flux growth of bulk GaN. Part II: in situ investigation of growth processes

作者：Von Dollen Paul^*; Pimputkar Siddha; Alreesh Mohammed Abo; Nakamura Shuji; Speck James S

来源：Journal of Crystal Growth, 2016, 456: 67-72.

DOI：10.1016/j.jcrysgro.2016.08.018

• Na flux method
• Growth rate
• Growth from high temperature solutions
• Sodium flux growth
• Nitrides
• III-Nitrides
• Bulk GaN

We report recent results of bulk GaN crystal growth using the sodium flux method in a new crucible-free growth system. We observed a (0001) Ga face (+c-plane) growth rate > 50 mu m/h for growth at a N-2 overpressure of 5 MPa and 860 degrees C, which is the highest crystal growth rate reported for this technique to date. Omega X-ray rocking curve (omega-XRC) measurements indicated the presence of multiple grains, though full width at half maximum (FWHM) values for individual peaks were < 100 arcseconds. Oxygen impurity concentrations as measured by secondary ion mass spectroscopy (SIMS) were > 10(20) atoms/cm(3). By monitoring the nitrogen pressure decay over the course of the crystal growth, we developed an in situ method that correlates gas phase changes with precipitation of GaN from the sodium-gallium melt. Based on this analysis, the growth rate may have actually been as high as 90 mu m/h, as it would suggest GaN growth ceased prior to the end of the run. We also observed gas phase behavior identified as likely characteristic of GaN polynucleation.

• 出版日期2016-12-15