High temperature growth of AlN film by LP‐HVPE

Abstract

AlN films were grown on AlN/sapphire templates at 1400–1500 °C using low‐pressure hydride vapor phase epitaxy (LP‐HVPE). Compared to the step‐flow growth of AlN film at 1200 °C with growth rate of 2.1 μm/h, AlN films with atomic steps were obtained at 1400–1500 °C even with high growth rate. For the AlN film grown at 1450 °C with growth rate of 14.3 μm/h, the RMS value is 0.75 nm and the FWHM values of (0002) and (10‐12) X‐ray rocking curve (XRC) are 351 and 781 arcsec, respectively. Since the FWHM value of (10‐12) XRC for the AlN/sapphire template is 1492 arcsec, the crystal quality of HVPE‐grown AlN is greatly improved compared with the AlN/sapphire template, which is also confirmed by TEM observation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

High-temperature growth of thick AlN layers on sapphire (0 0 0 1) substrates by solid source halide vapor-phase epitaxy

“…In recent years, our group has succeeded in growing thick AlN layers by HVPE using the aluminum trichloride (AlCl 3 ) and NH 3 as an Al and N precursors, respectively [8][9][10]. Also, several groups tried to grow AlN layers by same methods [11]. However, the growth temperature for AlN by HVPE was restricted by the softening point of quartz reactor at around 1200 1C.…”

Low-pressure HVPE growth of crack-free thick AlN on a trench-patterned AlN template

“…Moreover, several research groups have reported the growth of AlN layer on a sapphire or SiC substrate by HVPE [3][4][5][6][7]. We have recently demonstrated the fabrication of a thick AlN layer by lowpressure HVPE (LP-HVPE) on an AlN/sapphire template [8] and have also improved the crystal quality and surface morphology by high-temperature (41300 1C) growth [9]. However, the formation of cracks due to the large difference in thermal expansion coefficient between AlN and sapphire is considered a critical issue.…”

HVPE growth of thick AlN on trench‐patterned substrate

“…By ω-scan X-ray rocking curve (XRC) measurements, full-width at half-maximum (FWHM) values for (0002) and (10-10) diffractions of the 5μm groove-width were 223 and 630 arcsec, and the 15μm groove-width were 220 and 525 arcsec, respectively. The estimated screw and edge dislocation densities of the 5μm groove-width were 5.2x10 7 cm -2 and 1.1x10 9 cm -2 , and the 15μm groove-width were 4.6x10 7 cm -2 and 7.4x10 8 cm -2 , respectively [3]. In order to control the height of void -bottoms (h b ), we fabricated AlN templates with various stripe pattern and thick AlN layer were grown by HVPE.…”

“…In order to achieve high efficiency AlGaN-based DUV-LEDs, the development of a low threading dislocation density (TDD) AlN template is quite important. Hydride vapor phase epitaxy (HVPE) is expected for fabricating thick AlN film for the substrate [3], but it is still difficult for growth of the high-quality and crack-free thick AlN due to large difference thermal expansion coefficients and lattice constants between AlN and sapphire substrate.…”