Indium kinetics during the plasma-assisted molecular beam epitaxy of semipolar (11−22) InGaN layers

Abstract

We report on the growth kinetics of semipolar ͑11− 22͒ InGaN layers by plasma-assisted molecular beam epitaxy. Similarly to ͑0001͒-oriented InGaN, optimum growth conditions for this crystallographic orientation correspond to the stabilization of two atomic layers of In on the growing InGaN surface, and the limits of this growth window in terms of substrate temperature and In flux lie at same values for both polar and semipolar material. However, in semipolar samples, the incorporation of In is inhibited, even for growth temperatures within the Ga-limited regime of polar InGaN growth.

Comparative study of polar and semipolar (112¯2) InGaN layers grown by metalorganic vapour phase epitaxy

“…17) show the opposite trend, whereby the (0001) films had a higher indium incorporation. Das et al 16 proposed that the decreased indium incorporation was related to the surface roughness of the semi-polar surface, but the smooth surface maintained in the study by Browne et al indicates that the low indium incorporation is more likely related to the conditions used for MBE growth. 17 Here, we have conducted a study on the MOVPE growth of 25-30 nm-thick InGaN layers simultaneously on ð11 22Þ and (0001) GaN templates as a function of the InGaN growth temperature.…”

“…The few reported comparative MOVPE growth studies suggest that semipolar ð11 22Þ have a higher indium incorporation rate than polar and nonpolar planes, 2,13,14 or demonstrate that indium incorporation is virtually independent of the growth plane. 15 In contrast, ð11 22Þ InGaN epilayers grown by plasmaassisted molecular beam epitaxy (PAMBE) 16 and ammonia-MBE (Ref. 17) show the opposite trend, whereby the (0001) films had a higher indium incorporation.…”

Growth and characterization of polar (0001) and semipolar (11−22) InGaN/GaN quantum dots

“…1). However, the In incorporation is different for polar and semipolar layers grown simultaneously [14]. In polar samples, the In incorporation is limited by the Ga supply at low temperature and decreases for growth temperatures higher than a certain threshold due to In segregation.…”

“…1 corresponds to the stabilization of 2 ML of In on GaN [14], although the atomic density of these semipolar monolayers is approximately half the atomic density of a (0 0 0 1)-oriented layer [14,15]. Looking at this figure, we can conclude that it is practical to grow polar and semipolar InGaN layers simultaneously, since the limits of their stability windows in terms of substrate temperature and In flux lie at same values for both polar and semipolar material (see dashed lines in Fig.…”

Morphology and origin of V-defects in semipolar (11–22) InGaN

“…However, such pits have been attributed to the island coalescence during growth. In the case of semipolar (112 2) InGaN, a strong tendency to faceted growth when deposited by plasma-assisted molecular beam epitaxy (PA-MBE) was previously reported [15]. This has been attributed to a modification of the surface energy in the presence of indium, and it is interesting to examine if a correlation between structural defects and surface pits can be established similar to the polar case.…”