PRESENTATION

Efficient Diameter Enlargement of Bulk AlN

Bulk AlN substrates with high structural quality are best suited to exploit the full potential of AlGaN-based (opto)electronic devices. However, further development and commercialization is hindered by the lacking availability of high quality AlN substrates in terms of quantity and size. So far, the diameter expansion has been limited by the low lateral growth rates or the formation of defects. In this paper, we report on a fast increase of the crystal diameters by subsequent growth runs with huge expansion angles of about 45°. The high structural quality of the first seed generation can be preserved (dislocation density TDD ~ 103cm-2). First epi ready 2-inch AlN substrates are demonstrated. The process outlines a shortcut path to industrially relevant AlN crystal diameters of 100 mm or more compared to all other published expansion processes for bulk AlN crystals so far.