Figure 1a

Reflection high-energy electron diffraction (RHEED) from a clean Si (111) surface at 825°C, showing the (7x7) surface reconstruction. All the RHEED patterns are displayed as negative images for clarity.

Figure 1b

RHEED from the clean Si (111) surface at 835°C

Figure 1c

AlN nucleated 25° below the (7x7) transition, 45 seconds after start of growth.

Figure 1d

6 minutes after start of growth; substrate temperature has been ramped to ~875°C

Figure 1e

End of 2 hour growth ~2000Å AlN.

Figure 1f

On cooling after growth of ~1µm GaN on AlN buffer layer. The 2x reconstruction is thought to be characteristic of Ga-face material.

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© 1998 The Materials Research Society