An instrument for <i>in situ</i> coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

Ju, Guangxu; Highland, Matthew J.; Yanguas‐Gil, Angel; Thompson, Carol; Eastman, Jeffrey A.; Zhou, Hua; Brennan, S.; Stephenson, G. B.; Fuoss, P. H.

doi:10.1063/1.4978656

Cited by 15 publications

(17 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The substrate temperature was determined within 65 K by calibration using thermal expansion of a standard sapphire substrate measured by optical interferometry. 12 In the previous study, 5 we found conditions under which layer-by-layer growth occurs by observing the extent to which the intensity of the crystal truncation rod (CTR) scattering oscillates in time during growth, with maxima at the completion of each ML of growth. Here, we study the diffuse scattering that occurs around the CTR when islands are present on the surface between the completion of each ML, allowing us to determine the spacing of the islands and how it varies with growth conditions.…”

mentioning

confidence: 99%

Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Perret

Highland

et al. 2017

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

Using in situ grazing-incidence x-ray scattering, we have measured the diffuse scattering from islands that form during layer-by-layer growth of GaN by metal-organic vapor phase epitaxy on the (1010) m-plane surface. The diffuse scattering is extended in the ( 0001) in-plane direction in reciprocal space, indicating a strong anisotropy with islands elongated along [1210] and closely spaced along [0001]. This is confirmed by atomic force microscopy of a quenched sample. Islands were characterized as a function of growth rate G and temperature. The island spacing along [0001] observed during the growth of the first monolayer obeys a power-law dependence on growth rate G −n , with an exponent n = 0.25 ± 0.02. Results are in agreement with recent kinetic Monte Carlo simulations, indicating that elongated islands result from the dominant anisotropy in step edge energy and not from surface diffusion anisotropy. The observed power-law exponent can be explained using a simple steady-state model, which gives n = 1/4.

show abstract

mentioning

confidence: 99%

Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Perret

Highland

et al. 2017

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…We have used these in the past to model other configurations, such as vertical MOCVD reactors, with strong thermal gradients. 15 Likewise, it is possible to generalize the model to consider turbulent flow conditions. Both conditions are outside the scope of the present work.…”

Section: Methodsmentioning

confidence: 99%

Reactor scale simulations of ALD and ALE: ideal and non-ideal self-limited processes in a cylindrical and a 300 mm wafer cross-flow reactor

Yanguas‐Gil¹,

Libera²,

Elam³

2021

Preprint

Self Cite

View full text Add to dashboard Cite

We have developed a simulation tool to model self-limited processes such as atomic layer deposition and atomic layer etching inside reactors of arbitrary geometry. In this work, we have applied this model to two standard types of cross-flow reactors: a cylindrical reactor and a model 300 mm wafer reactor, and explored both ideal and non-ideal self-limited kinetics. For the cylindrical tube reactor the full simulation results agree well with analytic expressions obtained using a simple plug flow model, though the presence of axial diffusion tends to soften growth profiles with respect to the plug flow case. Our simulations also allowed us to model the output of in-situ techniques such as quartz crystal microbalance and mass spectrometry, providing a way of discriminating between ideal and non-ideal surface kinetics using in-situ measurements. We extended the simulations to consider two non-ideal self-limited processes: soft-saturating processes characterized by a slow reaction pathway, and processes where surface byproducts can compete with the precursor for the same pool of adsorption sites, allowing us to quantify their impact in the thickness variability across 300 mm wafer substrates.

show abstract

“…Usually synchrotron-based X-ray sources are used to obtain sufficient brightness for real-time measurements. The technique was employed for in situ monitoring of both MOVPE [37,38] and MBE [39]. In either case the growth chamber must be equipped with beryllium windows for both the entrance of the X-ray beam and the exit of the scattered X-rays.…”

Section: Grazing Incidence X-ray Diffraction (Gixd) and Reflectionmentioning

confidence: 99%

In Situ Growth Analysis

Pohl

2020

Graduate Texts in Physics

View full text Add to dashboard Cite

Sensors to analyse layer structures already during epitaxial growth provide valuable information for developing device structures and for ensuring the reproducibility of run-to-run conditions. Most analytical online tools are applicable to all major growth techniques. Today a variety of probes is routinely integrated into growth systems for monitoring in situ sample temperature, growth rate, layer thickness, composition, strain, and other parameters of the growth process. Sensors measure either the ambient in the vicinity of the growing sample or the sample surface. Ambient analysis comprises mass spectrometry and optical probes; they provide information about the mass transport, the kind and density of species, their temperature, and potential mutual reactions. Surface probes include diffraction techniques and various optical tools. Surface sensitivity for diffraction is achieved by applying grazing-incidence angles, and the diffracted electron and X-ray beams disclose the surface morphology and reconstructions. Optical probes are widely applied in gaseous growth ambient. The selectivity for the surface may strongly be enhanced by taking advantages of symmetry-related surface properties, and several optical probes can resolve the growth of single monolayers. The chapter describes prominent techniques for in situ analysis of epitaxy. After discussing ambient analysis using mass spectrometry and optical spectroscopy, surface probes are considered. Structural analysis by reflection high-energy electron diffraction and by X-ray diffraction is outlined, and optical probes by pyrometry and deflectometry yielding data on temperature and strain are presented. The text then focuses on reflectometry, ellipsometry, and reflectance-difference spectroscopy (reflectance-anisotropy spectroscopy); these techniques provide both chemical and structural information. Surface and Ambient ProbingSemiconductor devices consist of many epitaxial layers with different composition. The demand to control the perfection of growth in situ, i.e., already during epitaxy, led to the development of various analytical tools. Some of these sensors are today routinely integrated into commercial growth systems and allow for online monitoring

show abstract

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

Cited by 15 publications

References 36 publications

Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Reactor scale simulations of ALD and ALE: ideal and non-ideal self-limited processes in a cylindrical and a 300 mm wafer cross-flow reactor

In Situ Growth Analysis

Contact Info

Product

Resources

About