Extent of hydrogen coverage of Si(001) under chemical vapor deposition conditions from <i>ab initio</i> approaches

Rosenow, Phil; Tonner, Ralf

doi:10.1063/1.4952603

Cited by 12 publications

(7 citation statements)

References 47 publications

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“…, despite uncertainties in the parameters, and the simplifications assumed in the model. The results shown in Figure are also in line with more sophistaced density functional theory calculations published recently …”

Section: Resultssupporting

confidence: 91%

Control Over Dimer Orientations on Vicinal Si(100) Surfaces in Hydrogen Ambient: Kinetics Versus Energetics

Brückner

Supplie

Dobrich

et al. 2017

Physica Status Solidi (b)

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In chemical vapor ambience, Si(100) surfaces and hydrogen are strongly interacting with each other at relevant process temperatures. Energetic considerations cannot solely describe step and terrace formation sufficiently, as the formation of equilibrium surface reconstructions can be counteracted by surface kinetics. In recent years, the combination of in situ reflection anisotropy spectroscopy (RAS) and complementary UHV‐based surface sensitive techniques helped to understand and control the entire Si(100) surface preparation, in particular step and domain formation, which strongly depend on the applied process conditions and surface misorientation. Here, we discuss vicinal, 6° misoriented Si(100) surfaces in comparison to results on larger terraces in order to derive a general view on how to promote either a kinetically or an energetically driven step formation. Dictated by the dominant driving force, monohydride Si(100) surfaces with “A‐type” (1 × 2) or “B‐type” (2 × 1) majority domain can be prepared, as we confirm with RAS as well as low energy electron diffraction, scanning tunneling microscopy and Fourier‐transform infrared spectroscopy. Well‐ordered DB double layer steps at the vicinal B‐type Si(100) surface cause a step‐related, derivative‐like RAS signal, in contrast to all other surfaces. In general, we confirm that high H2 pressures promote kinetically driven processes, while the impact of energetics increases with offcut magnitude.

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Section: Resultssupporting

confidence: 91%

Control Over Dimer Orientations on Vicinal Si(100) Surfaces in Hydrogen Ambient: Kinetics Versus Energetics

Brückner

Supplie

Dobrich

et al. 2017

Physica Status Solidi (b)

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“…Diffusion of hydrogen or, in analogy, hydrogen vacancies, was found to be anisotropic with moderate barriers on one dimer and along the Si−Si dimer rows and a larger barrier perpendicular to the rows . This trend was also found by first‐principles calculations . These findings lead to the conclusion that most of the Si(001) surface is hydrogen‐covered at growth conditions but low concentrations of hydrogen vacancies [Si⋅] are to be expected on the length and time scales of the experiments presented here.…”

Section: Introductionsupporting

confidence: 75%

“…This mechanism and the diffusion of atomic hydrogen were previously studied by means of STM . Ab initio thermodynamics investigations also support partial dehydrogenation at elevated temperatures . Thus, unsaturated [Si⋅] surface sites are very likely to occur by one of these mechanisms under MOVPE conditions and they are known to determine the surface reactivity of H/Si(001)…”

Section: Introductionmentioning

confidence: 92%

Surface Chemistry of tert‐Butylphosphine (TBP) on Si(001) in the Nucleation Phase of Thin‐Film Growth

Stegmüller

Werner

Reutzel

et al. 2016

Chemistry A European J

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We combine density functional theory calculations and scanning tunneling microscopy investigations to identify the relevant chemical species and reactions in the nucleation phase of chemical vapor deposition. tert-Butylphosphine (TBP) was deposited on a silicon substrate under conditions typical for surface functionalization and growth of semiconductor materials. On the activated hydrogen-covered surface H/Si(001) it forms a strong covalent P-Si bond without loss of the tert-butyl group. Calculations show that site preference for multiple adsorption of TBP is influenced by steric repulsion of the adsorbate's bulky substituent. STM imaging furthermore revealed an anisotropic distribution of TBP with a preference for adsorption perpendicular to the surface dimer rows. The adsorption patterns found can be understood by a mechanism invoking stabilization of surface hydrogen vacancies through electron donation by an adsorbate. The now improved understanding of nucleation in thin-film growth may help to optimize molecular precursors and experimental conditions and will ultimately lead to higher quality materials.

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“…In situ RAS during cooling from 1000 °C in 950 mbar H 2 ambient verified that Si(100) is terminated by monohydrides at temperatures below 800 °C . The dependence of the H coverage depends highly on MOVPE process temperature and reactor pressure …”

Section: Epitaxial Reference Surfacesmentioning

confidence: 91%

In Situ Characterization of Interfaces Relevant for Efficient Photoinduced Reactions

Supplie

May

Brückner

et al. 2017

Adv Materials Inter

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which he pioneered and established. In general, interfaces do not only determine electronic properties of the final device; their atomic order also highly affects growth kinetics and defect formation. Moreover, the design of solid-liquid and hybrid interfaces determines their chemical reactivity and stability. In situ monitoring of interface preparation, formation, and interfacial reactions thus promises efficient process control. Paired with a detailed understanding of interface formation mechanisms, however, the true power of in situ control is to allow for specific modification and tuning of interface formation for the device of choice. There are several excellent reviews on in situ approaches covering wide ranges of materials from basic science to applications as well as varieties of preparation and analysis techniques. [2][3][4][5][6][7][8][9][10][11] As indicated in Figure 1, this review will be focused on in situ control over interfaces of materials that are relevant for photoinduced reactions in high-efficiency solar energy conversion and sensing applications with in situ control of semiconductor/polymer/ biological interfaces. We will restrict the techniques to realistic and complex, non-ultrahigh-vacuum (UHV) ambient, where in situ control is most demandingbut also highly desired. The more complex the interfacial reactions are, the more important is the in situ characterization. Ex situ approaches can contribute to an indirect understanding of interface formation, but to understand and, finally, control the dynamic processes taking place, real-time measurements are appropriate. The challenge, we are facing, is twofold: On the one hand, increased interaction with the surrounding ambient causes higher complexity. Yet at the same time, it decreases the number of applicable techniques. On the other hand, those techniques are often elaborate and not necessarily easy to interpret. In a nutshell, we will discuss four main topics:(i) Surface preparation during growth of structures for highefficiency solar energy conversion: World-record conversion efficiencies in both photovoltaics [12,13] and solar water splitting [14] are achieved with multijunction solar cells based on epitaxial III/V compound semiconductor structures. We will discuss in situ controlled preparation Solar energy conversion and photoinduced bioactive sensors are representing topical scientific fields, where interfaces play a decisive role for efficient applications. The key to specifically tune these interfaces is a precise knowledge of interfacial structures and their formation on the microscopic, preferably atomic scale. Gaining thorough insight into interfacial reactions, however, is particularly challenging in relevant complex chemical environment. This review introduces a spectrum of material systems with corresponding interfaces significant for efficient applications in energy conversion and sensor technologies. It highlights appropriate analysis techniques capable of monitoring critical physicochemical reactions in situ during non-vacuu...

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Extent of hydrogen coverage of Si(001) under chemical vapor deposition conditions from ab initio approaches

Cited by 12 publications

References 47 publications

Control Over Dimer Orientations on Vicinal Si(100) Surfaces in Hydrogen Ambient: Kinetics Versus Energetics

Control Over Dimer Orientations on Vicinal Si(100) Surfaces in Hydrogen Ambient: Kinetics Versus Energetics

Surface Chemistry of tert‐Butylphosphine (TBP) on Si(001) in the Nucleation Phase of Thin‐Film Growth

In Situ Characterization of Interfaces Relevant for Efficient Photoinduced Reactions

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