Cm. Balkas et al., SUBLIMATION GROWTH AND CHARACTERIZATION OF BULK ALUMINUM NITRIDE SINGLE-CRYSTALS, Journal of crystal growth, 179(3-4), 1997, pp. 363-370
Single crystalline platelets of aluminum nitride (AIN) less than or eq
ual to 1 mm thick have been grown within the temperature range of 1950
-2250 degrees C on 10 x 10 mm(2) alpha(6H)-silicon carbide (SiC) subst
rates via sublimation-recondensation in a resistively heated graphite
furnace. The source material was sintered AIN. A maximum growth rate o
f 500 mu m/h was achieved at 2150 degrees C and a source-to-seed separ
ation of 4 mm. Growth rates below 2000 degrees C were approximately on
e order of magnitude lower. Crystals grown at high temperatures ranged
in color from blue to green due to the incorporation of Si and C from
the SiC substrates; those grown at lower temperatures were colorless
and transparent. Secondary-ion mass spectroscopy (SIMS) results showed
almost a two order of magnitude decrease in the concentrations of the
se two impurities in the transparent crystals. Plan view transmission
electron microscopy (TEM) of these crystals showed no line or planar d
efects. Raman spectroscopy and X-ray diffraction (XRD) studies indicat
ed a strain free material.