Nucleation Control in Physical Vapor Transport Growth of AlN Single Crystals on Polycrystal Tungsten Substrates

  • Honglei WU
  • Zuoyan QIN
  • Xueyong TIAN
  • Zhenhua SUN
  • Baikui LI
  • Ruisheng ZHENG
  • Ke WANG
Keywords: growth from vapor, single-crystal growth, nitrides, X-ray diffraction

Abstract

The improved resistively-heated furnace with two heaters established a vertical thermal gradient to control nucleation during AlN single crystals Physical Vapor Transport (PVT) growth on polycrystal tungsten substrates. During the high temperature (> 1850 °C) heating process, the reverse temperature field (i.e., the temperature difference between the sublimation zone and the crystalline zone ΔT < 0) was obtained to reduce the number of nuclei on the tungsten substrate. During growth, the proper positive values of ΔT T were chosen to content the supersaturation values (0.25 < S < 0.3). The reverse temperature condition during high temperature (> 1850 °C) cooling was fulfilled to avoid recrystallization on grown AlN crystal. AlN single crystals made through the method were characterized by X-ray diffractions (XRD) and Raman spectroscopy.

Published
2019-12-18
Section
ELECTRONIC AND OPTICAL MATERIALS