On the origin of reflectance-anisotropy oscillations during GaAs (0 0 1) homoepitaxy

Ortega‐Gallegos, J.; Guevara-Macías, L. E.; Ariza-Flores, A. David; Lastras-Martı́nez, L. F.; Balderas‐Navarro, R. E.; López-Estopíer, R.; Lastras‐Martínez, A.

doi:10.1016/j.apsusc.2017.12.244

Cited by 10 publications

(6 citation statements)

References 20 publications

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“…The Origin of RDS oscillations is less obvious than those of the morphology-related responses of RHEED and GIXD, which are due to long-range order; RDS studies for GaAs at two energies 2.6 and 1.9 eV, which according to calculations are respectively characteristic of dimers of As and Ga, indicate that oscillations are related to the periodic change of dimer orientations particularly near step edges [42]. More recent reports also emphasize the importance of the periodic modulation of orthorhombic surface strain associated to surface reconstruction [81].…”

Section: Reflectance-difference Spectroscopymentioning

confidence: 96%

In Situ Growth Analysis

Pohl

2020

Graduate Texts in Physics

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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

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Section: Reflectance-difference Spectroscopymentioning

confidence: 96%

In Situ Growth Analysis

Pohl

2020

Graduate Texts in Physics

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“…Since then, the technique has been widely used for the study of semiconductor surfaces and interfaces in growth environments. In particular, RAS studies on GaAs have not only demonstrated how the spectroscopy can be used to control epitaxial growth and the preparation of specific surface reconstructions, but also the possibility to investigate layer‐by‐layer removal of GaAs as a protective cap layer for the preparation of fresh surfaces was shown [66–68] . More recently, Sombiro et al.…”

Section: From Epitaxial Growth To Electrochemical Interface Monitoringmentioning

confidence: 99%

“…In particular, RAS studies on GaAs have not only demonstrated how the spectroscopy can be used to control epitaxial growth and the preparation of specific surface reconstructions, but also the possibility to investigate layer-by-layer removal of GaAs as a protective cap layer for the preparation of fresh surfaces was shown. [66][67][68] More recently, Sombiro et al have pointed out the utilization of RAS to extract etching rate and etch-depth resolution from the analysis of Fabry-Pérot oscillations generated by reactive ion etching of GaAs/AlGaAs multi-layer structures. [69] Also dry etching in hydrogen ambient was studied by Brückner et al, [70] who report that RAS reveals a layer-by-layer removal from Si(100) single-crystals in H 2 atmosphere at elevated temperatures.…”

Section: Application Of Ras In Surface Sciencementioning

confidence: 99%

Experimental and Computational Aspects of Electrochemical Reflection Anisotropy Spectroscopy: A Review

et al. 2023

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Electrode/electrolyte interfaces play a crucial role in many electrochemical energy conversion and storage technologies. Hence, a deep understanding of the interfacial structure, energetic alignment and processes is of high relevance and has triggered the development of a number of in situ and operando techniques. One approach for gaining information about the change in surface chemistry and structure on an atomic scale is reflection anisotropy spectroscopy (RAS). This review presents and discusses the continuing effort to develop RAS as an in situ optical probe for solid‐liquid interfaces under applied potentials. Experimental and computational basic principles are presented and key challenges of electrochemical RAS are highlighted. Furthermore, we exemplarily demonstrate the potential of the method for spectroelectrochemistry, focusing on indium phosphide‐ and gold‐aqueous electrolyte interfaces as exemplary case studies, and outline research directions for battery systems.

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“…Reflectance anisotropy spectroscopy (RAS) is a nondestructive optical and surface-sensitive technique well established for monitoring epitaxial and dry-etch processes [ 5 , 6 , 7 , 8 , 9 ]. For example, the use of RAS equipment has had enormous success in terms of monitoring epitaxial growth, providing information about thickness, doping, the presence of quantum dots, and surface re- or deconstruction [ 5 , 6 , 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

“…Figure11. RAS transient acquired at 3.05 eV photon energy during the RIE process for an n-GaAs layer with a charge carrier concentration between 10 17 to 10 19 cm −3 .…”

mentioning

confidence: 99%

Doped or Quantum-Dot Layers as In Situ Etch-Stop Indicators for III/V Semiconductor Reactive Ion Etching (RIE) Using Reflectance Anisotropy Spectroscopy (RAS)

et al. 2021

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Reflectance anisotropy spectroscopy (RAS), which was originally invented to monitor epitaxial growth, can—as we have previously shown—also be used to monitor the reactive ion etching of III/V semiconductor samples in situ and in real time, as long as the etching rate is not too high and the abrasion at the etch front is not totally chaotic. Moreover, we have proven that—using RAS equipment and optical Fabry‒Perot oscillations due to the ever-shrinking thickness of the uppermost etched layer—the in situ etch-depth resolution can be as good as ±0.8 nm, employing a Vernier-scale type measurement and evaluation procedure. Nominally, this amounts to ±1.3 lattice constants in our exemplary material system, AlGaAsSb, on a GaAs or GaSb substrate. In this contribution, we show that resolutions of about ±5.6 nm can be reliably achieved without a Vernier scale protocol by employing thin doped layers or sharp interfaces between differently doped layers or quantum-dot (QD) layers as etch-stop indicators. These indicator layers can either be added to the device layer design on purpose or be part of it incidentally due to the functionality of the device. For typical etch rates in the range of 0.7 to 1.3 nm/s (that is, about 40 to 80 nm/min), the RAS spectrum will show a distinct change even for very thin indicator layers, which allows for the precise termination of the etch run.

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On the origin of reflectance-anisotropy oscillations during GaAs (0 0 1) homoepitaxy

Cited by 10 publications

References 20 publications

In Situ Growth Analysis

In Situ Growth Analysis

Experimental and Computational Aspects of Electrochemical Reflection Anisotropy Spectroscopy: A Review

Doped or Quantum-Dot Layers as In Situ Etch-Stop Indicators for III/V Semiconductor Reactive Ion Etching (RIE) Using Reflectance Anisotropy Spectroscopy (RAS)

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