9.3 Growth Monitoring Using RHEED - Growth of GaN on a-Plane Sapphire
Figure 23 shows the GaN RHEED pattern on a-plane sapphire, which assumes
a c-plane orientation. It was noticed that AlN does not grow well on a-plane
sapphire, becoming polycrystalline. Therefore only a few monolayers of
AlN were deposited before GaN growth. The procedure followed was similar
to GaN growth on c-plane sapphire as described in the preceding section.
As can be seen, the RHEED pattern was comparable in quality to c-plane
grown GaN, even though the AlN buffer layer did not grow well. More studies
are needed to confirm this preliminary result.
Figure 23: 112(bar)0 and 11(bar)00 RHEED pattern
of GaN on a-plane sapphire. Note that the closely regularly spaced streaks
were due to a faulty CCD-camera.
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