Figures

Figure 1

Schematic of pendeo-epitaxial growth of GaN from etched GaN (1 1  0) sidewalls and over a silicon nitride mask.

Figure 2

Cross-sectional SEM of a GaN pendeo-epitaxial growth structure with limited vertical growth from the seed sidewalls and no growth on the seed mask.

Figure 3

Cross-sectional SEM of a GaN/Al10Ga90N pendeo epitaxial growth structure showing coalescence over a seed mask.

Figure 4

Cross-sectional TEM of a GaN pendeo-epitaxial structure showing confinement of threading dislocations under the seed mask, and a reduction of defects in the regrowth area.

Figure 5a

Micrographs taken via cross-sectional SEM of examples of masked pendeo-epitaxial growth with coalescence over and between the seed forms resulting in a single GaN layer.

Figure 5b

Micrographs taken via plan-view SEM of examples of masked pendeo-epitaxial growth with coalescence over and between the seed forms resulting in a single GaN layer.

Figure 6

Low temperature (7K) photoluminescence spectrum of a coalesced layer of pendeoepitaxial GaN grown on a GaN/AlN/6H-SiC substrate.

Figure 7

Cross-sectional SEM micrograph of a coalesced PE GaN epilayer deposited on a masked GaN/AlN/3C-SiC/Si(111) substrate.

Figure 8

Double crystal XRD analysis of the tilting in the coalesced PE films.

Figure 9a

TEM selected area diffraction patterns from (a) a small section of coalesced PE GaN over a trench region and (b) a small area of PE GaN imaged from an area over the silicon nitride mask.

Figure 9b

see caption for Figure 9a

Figure 10

TEM micrograph of a GaN film grown over a silicon nitride mask. The coalescence boundary acted as a nucleation source for horizontally oriented dislocations.

Figure 11

Room temperature photoluminescence of a coalesced layer of PE GaN grown on a GaN/AlN/3C-SiC/Si(111) substrate.

Figure 12

Comparison of low-temperature (14K) PL spectra of PE GaN grown on GaN/AlN/6H-SiC and GaN/AlN/3C-SiC/Si(111) substrates.

Figure 13a

GaN film grown on unmasked, submicron wide stripes of a GaN/AlN/6H-SiC(0001) substrate. No misregistry above the GaN stripes was observed.

Figure 13b

TEM micrograph of the sample shown in (a). A significant reduction in the density of threading dislocations has been obtained in the PE GaN compared to the GaN stripes.

Figure 14a

Al10Ga90N film grown via pendeo-epitaxy on unmasked GaN seed posts on a 6H-SiC substrate. No misregistry above the GaN seed posts is observable.

Figure 14b

TEM micrograph of the sample in (a). A significant reduction in density of threading dislocations in the pendeo-epitaxial Al10Ga90N compare to the GaN seed post is obvious.

Figure 15

Two-dimensional space plot of Raman line frequency of an uncoalesced PE GaN film (specifically a wing and stripe region). An increase in the line frequency represents a relaxation of strain in the material.

Figure 16

Photoluminescence (PL) spectra taken from the wing and stripe region of an uncoalesced PE GaN film. Note the FWHM value for the wing peak is <300 µeV.

Figure 17a

Coalesced GaN films grown on un-masked GaN stripes on a GaN/AlN/3C-SiC/Si(111) substrate. No misregistry above the GaN seed post was observed.

Figure 17b

TEM micrograph of the sample in (a). A significant reduction in density of threading dislocations occurred in the pendeo-epitaxial GaN compared to the GaN stripes.

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