Epitaxial Lateral Overgrowth of GaN with Chloride-Based Growth Chemistries in Both Hydride and Metalorganic Vapor Phase Epitaxy

Abstract

Epitaxial lateral overgrowth (ELO) of GaN on SiO 2 -masked (0001) GaN substrates has been investigated by using chloride-based growth chemistries via hydride vapor phase epitaxy (HVPE) and metal organic vapor phase epitaxy (MOVPE). Diethyl gallium chloride, (C 2 H 5 ) 2 GaCl, was used in as the MOVPE Ga precursor. The lateral and vertical growth rates as well as the overgrowth morphology of ELO GaN structures are dependent on growth temperature, V/III ratio and the in-plane orientation of the mask opening. A high growth temperature and low V/III ratio increase the lateral growth rate and produce ELO structures with a planar surface to the GaN prisms. High-quality coalesced and planar ELO GaN has been fabricated by both growth chemistries. The use of the diethyl gallium chloride source allows for the benefits of HVPE growth to be realized within the MOVPE growth environment.

Epitaxial Lateral Overgrowth of GaN

“…Therefore the basic features described in Section 3.2.1 are observed [102,103]. This alternative method might be interesting for achieving high growth rates.…”

Demonstration of crystal–vapor equilibrium leading to growth blockade of GaN during selective area growth

“…For example, the experimental work of Li et al [20] demonstrated that the carrier gas composition (H 2 /N 2 ) in combination with the polarity of the GaN facets enhanced the formation of 1100 vertical sidewalls in submicrometer GaN rods. Only a few investigations have been made by SAG-HVPE: (i) Wang et al [21] have reported the influence of the growth temperature and reactor pressure on crack density in thick layers and (ii) Zhang et al [22] have proved that both the growth rate and the shape of GaN prisms were dependent on the growth conditions and on the orientation of the window opening.…”

Complete HVPE experimental investigations: Cartography of SAG GaN towards quasi-substrates or nanostructures

“…Several papers on the MOVPE process have reported the crystallographic morphology dependence on the growth temperature, the fill factor and the V/III ratio [22][23][24][25] whatever the stripe orientations /1 1 À2 0S or /1 À 1 0 0S on GaN templates. Hiramatsu et al [26] have observed that the stripe shape along the /1 1 À 2 0S direction was limited by N-polar {1 À 1 0 1} pyramid facets and did not depend on the partial pressures and the growth temperature.…”

“…This was ascribed to surface energy and facets stability considerations. The influence of the growth temperature and the V/III ratio on the lateral and vertical growth rates was clearly discussed [22][23][24][25]. MOVPE Facet Controlled Epitaxial Lateral Overgrowth (FACELO) technique was also developed [25].…”

“…Only few investigations have been made by ELO HVPE: (i) Wang et al [27] have reported the influence of the growth temperature and reactor pressure on the crack density in thick layers; (ii) Zhang et al [24] have proved that both the growth rate and the shape of GaN prisms were dependent on the growth conditions and on the orientation of the window opening. High growth temperatures and low V/III ratios were demonstrated to be efficient in enhancing the lateral overgrowth.…”