Transmission Electron Microscope Observation of Cubic GaN Grown by Metalorganic Vapor Phase Epitaxy with Dimethylhydrazine on (001) GaAs

Abstract

Cross-sectional transmission electron microscope observation has been performed on the microstructure of GaN films grown on a (001) GaAs substrate by metalorgahic vapor phase epitaxy (MOVPE) using 1,1-dimethylhydrazine (DMHy) and trimethylgallium (TMG) as the sources of nitrogen and gallium, respectively. Before the deposition, the surface of the substrate was nitrided with DMHy. High-resolution images and electron diffraction patterns confirmed that the GaN films have a zincblende structure (β-GaN) with the lattice constant of a GaN=0.454 nm, and contain bands of stacking faults parallel to {111} planes. The interface between GaN and GaAs is made of {111} facets with no interlayer. Misfit dislocations are found to be inserted on the interface approximately every five atomic planes of GaAs. The nitridation treatment with only DMHy for 130 min is found to form a thick layer of β-GaN on the (001) GaAs substrate. Nuclei of β-GaN formed by the pretreatment of surface nitridation play an important role in growing GaN in a zincblende structure during the supply of DMHy and TMG. The formation of facets on the top surface of GaN and on the interface of GaN/GaAs is explained in terms of the diffusion of arsenic in β-GaN. The characteristics of the structure of GaN films grown at 600 and 650° C are also presented.

Effect of the nitridation process on cubic GaN film quality grown on AlGaAs buffer layer by RF‐MBE

“…1 and 2, it is concluded that the formation of a smooth and uniform nucleation layer (AlGaN) and suppression of {111} facets formation were essential to realize high phase purity c-GaN epilayer growth. Similar results were reported by Kuwano et al [4] with c-GaN/GaAs (001). Figure 6 shows a 2θ-ω XRD scan using along the [100] axis of a c-GaN epilayer grown on an AlGaN surface formed by 10 seconds nitridation.…”

“…Recently, improvements in the crystallinity of nitride crystal growth for short nitridation times have been studied [2,3]. The nitridation process of the initial growth of c-GaN films on GaAs substrate has also been studied [4][5][6].In this work, a dramatic improvement in the reproducibility and stability of c-GaN epilayer growth was achieved by controlling {111} facet formation during the initial stage of growth by optimizing nitridation conditions. The crystallographic properties of the as-grown layers were characterized by reflection high-energy electron diffraction (RHEED) and high resolution X-ray diffraction (HR-XRD).…”

Materials Chemistry of Group 13 Nitrides

“…AlN seems to be different. The formation of (Me 2 AlNH 2 ) 3 amides in the gas phase as well as the surface-bound adducts [Me 2 AlNH 3 ] ads was observed [60][61][62]. Nothing is known about InN growth.…”

“…One drawback, however, is the high toxicity of hydrazine (TLV skin = 0.01 ppm) and the tendency toward explosive decomposition, which is catalyzed by traces of oxidants and various metals. Less dangerous alkyl derivatives of hydrazine, such as (CH 3 ) 2 N -NH 2 , have also been studied, but again gave unwanted carbon impurities at 550-650 • C and a V/III ratio of 160 : 1 [69][70][71]. Using hydrogen azide HN 3 , which is an even more dangerous compound [72], very good nitride films were grown at low temperatures using either OMVPE or MBE techniques [73].…”

Cross-Sectional Scanning Tunneling Microscopy Characterization of Cubic GaN Epilayers Grown on (001) GaAs

“…For example, an optical cavity is easily formed by cleavage and electrodes can be formed in the vertical configuration. However, the growth of high quality c-GaN epilayers has been prevented from inclusion of stable h-GaN and stacking faults in c-GaN epilayer [6].…”