Growth optimization for high quality GaN films grown by metal-organic chemical vapor deposition

2008 ◽  
Vol 1068 ◽  
Author(s):  
Jung Hun Jang ◽  
A M Herrero ◽  
Seungyoung Son ◽  
B Gila ◽  
C Abernathy ◽  
...  

ABSTRACTGaN layers were grown on c-plane sapphire substrates by using a conventional two step growth method via metal organic chemical vapor deposition (MOCVD). The effect of different growth conditions used in the deposition of the low temperature nucleation layer and high temperature islands on the crystalline quality of the GaN layers was investigated by high resolution X-ray diffraction (HRXRD) and transmission electron microscopy (TEM). The polar (tilt) and azimuthal (twist) spread were estimated from the full width at half maximum (FWHM) values of the omega rocking curves (¥ø-RCs) recorded from the planes parallel and perpendicular to the sample surface. It was found from the XRD and TEM study that the edge and mixed type threading dislocations are dominant defects so that the relevant figure of merit (FOM) for the crystalline quality should be considered only by the FWHM value of ¥ø-RC of the surface perpendicular plane. The result showed that the mixed- and edge-types dislocations were strongly associated with the growth conditions used in the deposition of the nucleation layer and high temperature islands.

1994 ◽  
Vol 340 ◽  
Author(s):  
R. M. Biefeld ◽  
K. C. Baucom ◽  
S. R. Kurtz

ABSTRACTWe have prepared InAsSb/InGaAs strained-layer superlattice (SLS) semiconductors by metal-organic chemical vapor deposition (MOCVD) using a variety of growth conditions. The presence of an InGaAsSb interface layer is indicated by the x-ray diffraction patterns. The optimized growth conditions involved the use of low pressure, short purge times between the growth of the layers, and no reactant flow during the purges. We used MOCVD to prepare an optically pumped, single heterostructure InAsSb/InGaAs SLS / InPSb laser which emitted at 3.9 μm with a maximum operating temperature of approximately 100 K.


1997 ◽  
Vol 12 (5) ◽  
pp. 1214-1236 ◽  
Author(s):  
Bruce J. Hinds ◽  
Richard J. McNeely ◽  
Daniel B. Studebaker ◽  
Tobin J. Marks ◽  
Timothy P. Hogan ◽  
...  

Epitaxial Tl2Ba2CaCu2O8 thin films with excellent electrical transport characteristics are grown in a two-step process involving metal-organic chemical vapor deposition (MOCVD) of a BaCaCuO(F) thin film followed by a postanneal in the presence of Tl2O vapor. Vapor pressure characteristics of the recently developed liquid metal-organic precursors Ba(hfa)2 • mep (hfa = hexafluoroacetylacetonate, mep = methylethylpentaglyme), Ca(hfa)2 • tet (tet = tetraglyme), and the solid precursor Cu(dpm)2 (dpm = dipivaloylmethanate) are characterized by low pressure thermogravimetric analysis. Under typical film growth conditions, transport is shown to be diffusion limited. The transport rate of Ba(hfa)2 • mep is demonstrated to be stable for over 85 h at typical MOCVD temperatures (120 °C). In contrast, the vapor pressure stability of the commonly used Ba precursor, Ba(dpm)2, deteriorates rapidly at typical growth temperatures, and the decrease in vapor pressure is approximately exponential with a half-life of ∼9.4 h. These precursors are employed in a low pressure (5 Torr) horizontal, hot-wall, film growth reactor for growth of BaCaCuO(F) thin films on (110) LaAlO3 substrates. From the dependence of film deposition rate on substrate temperature and precursor partial pressure, the kinetics of deposition are shown to be mass-transport limited over the temperature range 350–650 °C at a 20 nm/min deposition rate. A ligand exchange process which yields volatile Cu(hfa)2 and Cu(hfa) (dpm) is also observed under film growth conditions. The MOCVD-derived BaCaCuO(F) films are postannealed in the presence of bulk Tl2Ba2CaCu2O8 at temperatures of 720–890 °C in flowing atmospheres ranging from 0–100% O2. The resulting Tl2Ba2CaCu2O8 films are shown to be epitaxial by x-ray diffraction and transmission electron microscopic (TEM) analysis with the c-axis normal to the substrate surface, with in-plane alignment, and with abrupt film-substrate interfaces. The best films exhibit a Tc = 105 K, transport-measured Jc= 1.2 × 105 A/cm2 at 77 K, and surface resistances as low as 0.4 mΩ (40 K, 10 GHz).


Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 281 ◽  
Author(s):  
Zeming Li ◽  
Teng Jiao ◽  
Daqiang Hu ◽  
Yuanjie Lv ◽  
Wancheng Li ◽  
...  

β-Ga2O3 films were grown on sapphire (0001) substrates with various O/Ga (VI/III) ratios by metal organic chemical vapor deposition. The effects of VI/III ratio on growth rate, structural, morphological, and Raman properties of the films were systematically studied. By varying the VI/III ratio, the crystalline quality obviously changed. By decreasing the VI/III ratio from 66.9 × 103 to 11.2 × 103, the crystalline quality improved gradually, which was attributed to low nuclei density in the initial stage. However, crystalline quality degraded with further decrease of the VI/III ratio, which was attributed to excessive nucleation rate.


1996 ◽  
Vol 68 (10) ◽  
pp. 1371-1373 ◽  
Author(s):  
X. H. Wu ◽  
D. Kapolnek ◽  
E. J. Tarsa ◽  
B. Heying ◽  
S. Keller ◽  
...  

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