Figures

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.

Figure 2

Azimuthal x-ray diffraction scans on the GaN (1 0  2) peak. for four different GaN/Si samples.

Figure 3

TEM micrograph of a GaN/AlN/Si sample. The AlN was nucleated at 500°C and ramped immediately to 875°C for growth of the 2200Å thick buffer layer.

Figure 4

Illustration of 17:14 lattice matching on the 7x7 reconstruction of the (1 1 1) Si surface.

© 1998 The Materials Research Society