The role of gaseous species in group-III nitride growth

Karpov, S. Yu.; Makarov, Yu.N.; Ramm, M.G.

doi:10.1557/s109257830000171x

Cited by 30 publications

(7 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, regimes II (W254) and III (W239) allow the main InN layer to be grown at maximal possible T S $ 470 C, when the In/N flux ratio is close to 1: 1 at given N flux and In droplets do not occur. This temperature agrees well with a lower boundary of theoretically estimated region of an onset of fast N escape from InN, resulting in an excess of In on the surface [3]. RHEED for both InN layers demonstrates (1Â1) streaky patterns corresponding to a 2D growth.…”

Section: Resultssupporting

confidence: 86%

“…Indium nitride is considered as a promising material for optoelectronic devices, low-cost highefficiency solar cells, optical coatings, and various types of sensors [1]. However, due to a low dissociation temperature of InN (about 630 C [2]) and steep rising of nitrogen equilibrium vapor pressure with growth temperature (T S ) increase around 500 C [3], good quality InN epilayers are still not easily attainable. The lower growth temperatures and growth rates used in molecular beam epitaxy (MBE) could play a crucial role in growing the high quality InGaN alloys with high In content, necessary for achieving the green inter-band luminescence.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

MBE Growth of Hexagonal InN Films on Sapphire with Different Initial Growth Stages

Mamutin¹,

Vekshin

Davydov

et al. 1999

phys. stat. sol. (a)

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

MBE Growth of Hexagonal InN Films on Sapphire with Different Initial Growth Stages

Mamutin¹,

Vekshin

Davydov

et al. 1999

phys. stat. sol. (a)

View full text Add to dashboard Cite

“…Hence, the occurrence of phase separation is determined by competition between the thermodynamic driving force and the compressive stress imposed by the lattice mismatch between the QWs and the barrier layers. The calculations of Karpov [14] showed that the elastic compressive stresses in In x Ga 1Àx N layers could shift the miscibility gap towards higher In concentrations, resulting in the suppression of phase separation. This is consistent with our experimental results.…”

Section: Discussionmentioning

confidence: 99%

“…As a result, an In x Ga 1Àx N layer grown on a GaN layer will experience a compressive stress. The calculations of Karpov [14] showed that the elastic compressive stresses in In x Ga 1Àx N layers could shift the miscibility gap towards the higher In concentrations, leading to the suppression of phase separation in compositions where phase separation may be expected according to the calculations of Ho and Stringfellow [4]. Tabata et al [15] did not observe the Raman peak, which serves as the fingerprint of In-rich phase in Raman spectra obtained from pseudomorphic In x Ga 1Àx N layer ($3 nm) with 35% or 45% In.…”

Section: Introductionmentioning

confidence: 99%

Effects of stress on phase separation in InxGa1−xN/GaN multiple quantum-wells

et al. 2011

View full text Add to dashboard Cite

“…However, the mechanism by which N is incorporated at the surface could not be identified. Theoretically, only few studies to describe GaN growth have been reported, which were either based on thermodynamic models [6] or Monte Carlo simulations [7]. These approaches are useful to model growth on a mesoscopic scale.…”

mentioning

confidence: 99%

Adatom diffusion at GaN (0001) and (0001̄) surfaces

Zywietz

Neugebauer

Scheffler

1998

Applied Physics Letters

460

305

View full text Add to dashboard Cite

The diffusion of Ga and N adatoms has been studied for the technologically relevant wurtzite (0001) and (0001) surfaces employing density-functional theory. Our calculations reveal a very different diffusivity for Ga and N adatoms on the equilibrium surfaces: While Ga is very mobile at typical growth temperatures, the diffusion of N is by orders of magnitudes slower. These results give a very detailed insight of how and under which growth conditions N adatoms can be stabilized and efficiently incorporated at the surface. We further find that the presence of excess N strongly increases the Ga diffusion barrier and discuss the consequences for the growth of GaN.Recently, great progress in fabricating highly efficient GaN-based devices has been achieved [1,2]. Nevertheless, there are still substantial problems concerning growth optimization and insight into the fundamental mechanisms is rather shallow. Investigations of molecular beam epitaxy (MBE) growth have shown that the film structure and morphology are very sensitive to the III/V ratio [3,4]. GaN films grown under more N-rich conditions are rough and faceted while going towards more Ga-rich conditions a smoother surface morphology and better film quality are obtained [3].In order to improve growth in a systematic way it is essential to understand the underlying kinetic processes such as adsorption, desorption, and surface diffusion. In particular, adatom diffusion on surfaces is considered to be a key parameter controlling the growth rate, the material quality, and the surface morphology. Experimentally, an analysis of surface diffusion is difficult: So far only effective diffusion barriers have been obtained for GaN [4,5]. It is also not clear whether the cation or anion surface diffusion is the rate limiting process [4]. A problem in growing GaN is also the high N vapor pressure and considerable efforts have been made to enhance the N incorporation. However, the mechanism by which N is incorporated at the surface could not be identified. Theoretically, only few studies to describe GaN growth have been reported, which were either based on thermodynamic models [6] or Monte Carlo simulations [7]. These approaches are useful to model growth on a mesoscopic scale. However, the microscopic meaning of the effective parameters and the underlying microscopic processes remain unclear. In order to identify the fundamental growth mechanisms, but also to improve the above mentioned methods, the correct microscopic parameters are needed [8].We have therefore performed a comprehensive and detailed study of the migration and energetics of Ga and N adatoms on GaN surfaces, employing totalenergy density-functional theory calculations with ab initio pseudopotentials. We will focus on the two technologically relevant orientations for wurtzite GaN, the (0001) and the (0001) surfaces. The adatom substrate system is modeled by supercell geometries with at least 9 layers of GaN, a 14 bohr vacuum region and (2 × 2) periodicity. One side of the slab is passivated by fractional pseud...

show abstract

The role of gaseous species in group-III nitride growth

Cited by 30 publications

References 36 publications

MBE Growth of Hexagonal InN Films on Sapphire with Different Initial Growth Stages

MBE Growth of Hexagonal InN Films on Sapphire with Different Initial Growth Stages

Effects of stress on phase separation in InxGa1−xN/GaN multiple quantum-wells

Adatom diffusion at GaN (0001) and (0001̄) surfaces

Contact Info

Product

Resources

About