Analysis of crystal orientation in AlN layers grown on m-plane sapphire

Analysis of HVPE grown AlGaN layers on honeycomb patterned sapphire

“…2b) show the presence of twins for this orientation. This is typical for the (1-103) crystallites on m-plane sapphire [12][13][14]. Thus, the type 3 orientation can be identified with the semipolar (1-103)-orientation schematically shown in Fig.…”

“…It has been reported, that growth of group-III nitrides on mplane sapphire can result in three different orientations: nonpolar m-plane (1-100), as well as semipolar (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and (1-103) [12][13][14]. In our experiment, the PSS sidewalls represent m-planes of sapphire (see the cross-sectional sketch in Fig.…”

“…5. Their twinning behavior as well as a small inclination of the [11][12][13][14][15][16][17][18][19][20] axis with respect to the surface normal is confirmed by XRD measurements (see slightly rotated double peaks in Fig. 2b).…”

“…Also some intensity at the φ ¼ À1301 limit of the measurement gives rise to the interpretation of three equivalent double domains. These 11-20 peaks indicate the presence of nearly nonpolar a-plane oriented AlGaN crystallites in our sample, since the 11-20 peak position at 2.81 and 1.31 indicates a slight inclination of the [11][12][13][14][15][16][17][18][19][20] axis from the surface normal. The plot of the 10-10 AlGaN reflection also shows intensity with less contrast to the background, so a certain volume of crystallites with this different nonpolar orientation is apparently present in the sample.…”

Structural and electrical properties of semipolar (11‐22) AlGaN grown on m‐plane (1‐100) sapphire substrates

“…However, the growth of (11‐22) nitrides on m ‐plane sapphire has been suffered with the concomitant formation of the (1‐103) orientation . Various approaches to suppress the (1‐103) formation have been developed for GaN and InGaN , while the microstructure of AlN on m ‐plane sapphire was investigated in detail using transmission electron microscopy . Recently, we have fabricated phase‐controlled AlN on m ‐plane sapphire by tuning the growth conditions .…”