Epitaxial Growth and Orientation of GaN on (1 0 0) γ-LiAlO2

Abstract

The (1 0 0) face of γ -LiAlO 2 has attracted attention as a possible substrate for GaN epitaxial growth. This is partly because this face has an excellent lattice and structural match to (1 0 0) GaN. This orientation would have a misfit of only -1.4% along the c-direction and -0.1% along the b-direction of LiAlO 2 . We find that in practice this orientation relationship does not occur; instead, (0 0 0 1) oriented GaN grows with a small tilt (0.6° towards the c-direction) between the film and substrate. Although the misfit along the substrate b direction is large (-6.3%) for this orientation, the tilt perfectly accommodates the -1.4% misfit in the c direction. We present characterization of these films by RHEED, X-ray diffraction, and TEM. We propose that the tilt is driven by a reduction of interface energy which occurs in polar, incoherent interfaces.

Low temperature growth of c-axis oriented AlN films on γ-LiAlO2 by radio frequency magnetron sputtering

“…From these figures it is observed that AlN (0 0 0 2) and AlN (0 0 0 4) diffraction peaks appear at 2θ ∼ 36.5 • and 2θ ∼ 77.5 • , respectively, because the films grows with a small tilt (∼0.23 • ) toward the ␥-LiAlO 2 c-axis, similar results were obtained in some study in GaN growth on ␥-LiAlO 2 substrate [14]. In addition, peaks of some oxide at 2θ ∼ 31.2 • appear due to the relative low base vacuum degree.…”

Highly efficient light emission from stacking faults intersecting nonpolar GaInN quantum wells

“…As an alternative, several groups have reported heteroepitaxial growth of non-polar GaN layers on foreign substrates (c-LiAlO 2 , SiC, r-plane sapphire). [5][6][7] However, most of these structures were affected by high densities of threading dislocations (TDs) and basal plane stacking faults (BSFs), which are terminated by either prismatic stacking faults (PSFs) or partial dislocations. 8 While TDs are known to act as nonradiative recombination centers, BSFs are optically active since they can be considered as cubic (zincblende) ABC phases in the wurtzite ABAB stacking sequence.…”

Development and prospects of nitride materials and devices with nonpolar surfaces

“…Over the years, GaN with different orientations have been shown practically by all growth techniques, HVPE [7,15], metalorganic vapor phase epitaxy (MOVPE) [9,10,14,[17][18][19][22][23][24][25][26], MBE [8,11,12,20,21,27]. For more than 20 years, all the publications consistently reported that the nitride growth in directions different from the [0001] one is more difficult.…”