Sublimation growth of 2 inch diameter bulk AlN crystals

Abstract

The technology of sublimation growth of 15 mm diameter bulk single AlN crystals is scaled to grow similar 2‐inch diameter crystals. The best results are currently achieved with the two‐stage technique including 1) seeding and initial growth of 2‐3 mm thick single‐crystal AlN layers on 2‐inch diameter 6H‐SiC wafers in pre‐carbonized Ta crucibles in graphite equipment and 2) growth of bulk AlN crystals on the above AlN layers in tungsten crucibles and equipment. The initial AlN layers prove of good crystallographic quality but may contain up to 6 at.% of Si impurities. The eventual bulk AlN crystals consist of about 40 mm diameter round single‐crystal core and polycrystalline rim. No impurities in concentration higher than 0.01 at.% are found in the bulk crystals. The bulk AlN crystal may be separated from the initial AlN layer to use the latter repeatedly for growth of a new crystal. Such “secondary” crystals were found to be semi‐insulating. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Development of 2" AlN Substrates Using SiC Seeds

“…This result is attributed to the effect of the residual impurities (primarily Si) that still remain in the AlN bulk crystals grown on the SiC seeds. Repeated use of the initial AlN layer separated from the "primary" crystal (Chemekova et al, 2008) results in high purity material with the resistivity in the range of 3 · 10 9 -3· 10 11 Ohm · cm, which is rather close to the reference values.…”

Investigation on AlN epitaxial growth and related etching phenomenon at high temperature using high temperature chemical vapor deposition process

“…Recent results can be found in Refs. [4][5][6][7]. However, the availability of large size, high quality and high purity AlN single crystals grown by PVT still is lacking to date.…”

AlN bulk single crystal growth on 6H-SiC substrates by sublimation method

“…AlN bulk single crystals have been grown by the sublimation method [1][2][3][4][5][6][7][8][9][10][11][12][13]. Initially, attention was focused on this method as a way of growing SiC bulk single crystal in the field of semiconductor materials [14].…”