1
|
Heintz A, Ilahi B, Pofelski A, Botton G, Patriarche G, Barzaghi A, Fafard S, Arès R, Isella G, Boucherif A. Defect free strain relaxation of microcrystals on mesoporous patterned silicon. Nat Commun 2022; 13:6624. [PMID: 36333304 PMCID: PMC9636155 DOI: 10.1038/s41467-022-34288-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
A perfectly compliant substrate would allow the monolithic integration of high-quality semiconductor materials such as Ge and III-V on Silicon (Si) substrate, enabling novel functionalities on the well-established low-cost Si technology platform. Here, we demonstrate a compliant Si substrate allowing defect-free epitaxial growth of lattice mismatched materials. The method is based on the deep patterning of the Si substrate to form micrometer-scale pillars and subsequent electrochemical porosification. The investigation of the epitaxial Ge crystalline quality by X-ray diffraction, transmission electron microscopy and etch-pits counting demonstrates the full elastic relaxation of defect-free microcrystals. The achievement of dislocation free heteroepitaxy relies on the interplay between elastic deformation of the porous micropillars, set under stress by the lattice mismatch between Ge and Si, and on the diffusion of Ge into the mesoporous patterned substrate attenuating the mismatch strain at the Ge/Si interface. Many complex devices rely on epitaxial growth with high crystallinity and accurate composition. Here authors report epitaxial growth of Ge on deep etched porous Si pillars to provide a fully compliant substrate enabling elastic relaxation of defect free Ge microcrystals.
Collapse
Affiliation(s)
- Alexandre Heintz
- grid.86715.3d0000 0000 9064 6198Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada ,grid.86715.3d0000 0000 9064 6198Laboratoire Nanotechnologies Nanosystèmes (LN2) —CNRS UMI-3463, Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada
| | - Bouraoui Ilahi
- grid.86715.3d0000 0000 9064 6198Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada ,grid.86715.3d0000 0000 9064 6198Laboratoire Nanotechnologies Nanosystèmes (LN2) —CNRS UMI-3463, Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada
| | - Alexandre Pofelski
- grid.25073.330000 0004 1936 8227Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4M1 Canada
| | - Gianluigi Botton
- grid.25073.330000 0004 1936 8227Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4M1 Canada ,grid.423571.60000 0004 0443 7584Canadian Light Source, 44 Innovation Boulevard, Saskatoon, SK S7N 2V3 Canada
| | - Gilles Patriarche
- Centre de Nanosciences et de Nanotechnologies – C2N, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
| | - Andrea Barzaghi
- grid.4643.50000 0004 1937 0327L-NESS and Dipartimento di Fisica, Politecnico di Milano, Via Anzani 42, I-22100 Como, Italy
| | - Simon Fafard
- grid.86715.3d0000 0000 9064 6198Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada ,grid.86715.3d0000 0000 9064 6198Laboratoire Nanotechnologies Nanosystèmes (LN2) —CNRS UMI-3463, Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada
| | - Richard Arès
- grid.86715.3d0000 0000 9064 6198Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada ,grid.86715.3d0000 0000 9064 6198Laboratoire Nanotechnologies Nanosystèmes (LN2) —CNRS UMI-3463, Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada
| | - Giovanni Isella
- grid.4643.50000 0004 1937 0327L-NESS and Dipartimento di Fisica, Politecnico di Milano, Via Anzani 42, I-22100 Como, Italy
| | - Abderraouf Boucherif
- grid.86715.3d0000 0000 9064 6198Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada ,grid.86715.3d0000 0000 9064 6198Laboratoire Nanotechnologies Nanosystèmes (LN2) —CNRS UMI-3463, Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, QC J1K OA5 Canada
| |
Collapse
|
2
|
Faceting of Si and Ge crystals grown on deeply patterned Si substrates in the kinetic regime: phase-field modelling and experiments. Sci Rep 2021; 11:18825. [PMID: 34552147 PMCID: PMC8458435 DOI: 10.1038/s41598-021-98285-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
The development of three-dimensional architectures in semiconductor technology is paving the way to new device concepts for various applications, from quantum computing to single photon avalanche detectors. In most cases, such structures are achievable only under far-from-equilibrium growth conditions. Controlling the shape and morphology of the growing structures, to meet the strict requirements for an application, is far more complex than in close-to-equilibrium cases. The development of predictive simulation tools can be essential to guide the experiments. A versatile phase-field model for kinetic crystal growth is presented and applied to the prototypical case of Ge/Si vertical microcrystals grown on deeply patterned Si substrates. These structures, under development for innovative optoelectronic applications, are characterized by a complex three-dimensional set of facets essentially driven by facet competition. First, the parameters describing the kinetics on the surface of Si and Ge are fitted on a small set of experimental results. To this goal, Si vertical microcrystals have been grown, while for Ge the fitting parameters have been obtained from data from the literature. Once calibrated, the predictive capabilities of the model are demonstrated and exploited for investigating new pattern geometries and crystal morphologies, offering a guideline for the design of new 3D heterostructures. The reported methodology is intended to be a general approach for investigating faceted growth under far-from-equilibrium conditions.
Collapse
|
3
|
Pedrini J, Biagioni P, Ballabio A, Barzaghi A, Bonzi M, Bonera E, Isella G, Pezzoli F. Broadband control of the optical properties of semiconductors through site-controlled self-assembly of microcrystals. OPTICS EXPRESS 2020; 28:24981-24990. [PMID: 32907029 DOI: 10.1364/oe.398098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
We investigate light-matter interactions in periodic silicon microcrystals fabricated combining top-down and bottom-up strategies. The morphology of the microcrystals, their periodic arrangement, and their high refractive index allow the exploration of photonic effects in microstructured architectures. We observe a notable decrease in reflectivity above the silicon bandgap from the ultraviolet to the near-infrared. Finite-difference time-domain simulations show that this phenomenon is accompanied by a ∼2-fold absorption enhancement with respect to a flat sample. Finally, we demonstrate that ordered silicon microstructures enable a fine tuning of the light absorption by changing experimentally accessible knobs as pattern and growth parameters. This work will facilitate the implementation of optoelectronic devices based on high-density microcrystals arrays with optimized light-matter interactions.
Collapse
|
4
|
Barzaghi A, Firoozabadi S, Salvalaglio M, Bergamaschini R, Ballabio A, Beyer A, Albani M, Valente J, Voigt A, Paul DJ, Miglio L, Montalenti F, Volz K, Isella G. Self-Assembly of Nanovoids in Si Microcrystals Epitaxially Grown on Deeply Patterned Substrates. CRYSTAL GROWTH & DESIGN 2020; 20:2914-2920. [PMID: 33828439 PMCID: PMC8016367 DOI: 10.1021/acs.cgd.9b01312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 04/08/2020] [Indexed: 06/11/2023]
Abstract
We present an experimental and theoretical analysis of the formation of nanovoids within Si microcrystals epitaxially grown on Si patterned substrates. The growth conditions leading to the nucleation of nanovoids have been highlighted, and the roles played by the deposition rate, substrate temperature, and substrate pattern geometry are identified. By combining various scanning and transmission electron microscopy techniques, it has been possible to link the appearance pits of a few hundred nanometer width at the microcrystal surface with the formation of nanovoids within the crystal volume. A phase-field model, including surface diffusion and the flux of incoming material with shadowing effects, reproduces the qualitative features of the nanovoid formation thereby opening new perspectives for the bottom-up fabrication of 3D semiconductors microstructures.
Collapse
Affiliation(s)
- Andrea Barzaghi
- L-NESS,
Dipartimento di Fisica, Politecnico di Milano, Via Anzani 42, 22100 Como, Italy
| | - Saleh Firoozabadi
- Materials
Science Center and Faculty of Physics, Philipps-Universität
Marburg, Hans-Meerweinstraße 6, 35032 Marburg, Germany
| | - Marco Salvalaglio
- Institute
of Scientific Computing, Technische Universität
Dresden, 01062 Dresden, Germany
- Dresden
Center for Computational Materials Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Roberto Bergamaschini
- L-NESS
and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| | - Andrea Ballabio
- L-NESS,
Dipartimento di Fisica, Politecnico di Milano, Via Anzani 42, 22100 Como, Italy
| | - Andreas Beyer
- Materials
Science Center and Faculty of Physics, Philipps-Universität
Marburg, Hans-Meerweinstraße 6, 35032 Marburg, Germany
| | - Marco Albani
- L-NESS
and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| | - Joao Valente
- James Watt
School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT, United Kingdom
| | - Axel Voigt
- Institute
of Scientific Computing, Technische Universität
Dresden, 01062 Dresden, Germany
- Dresden
Center for Computational Materials Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Douglas J. Paul
- James Watt
School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT, United Kingdom
| | - Leo Miglio
- L-NESS
and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| | - Francesco Montalenti
- L-NESS
and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| | - Kerstin Volz
- Materials
Science Center and Faculty of Physics, Philipps-Universität
Marburg, Hans-Meerweinstraße 6, 35032 Marburg, Germany
| | - Giovanni Isella
- L-NESS,
Dipartimento di Fisica, Politecnico di Milano, Via Anzani 42, 22100 Como, Italy
| |
Collapse
|
5
|
Dislocation Analysis in SiGe Heterostructures by Large-Angle Convergent Beam Electron Diffraction. CRYSTALS 2019. [DOI: 10.3390/cryst10010005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dislocations play a crucial role in self-organization and strain relaxation mechanisms in SiGe heterostructures. In most cases, they should be avoided, and different strategies exist to exploit their nucleation properties in order to manipulate their position. In either case, detailed knowledge about their exact Burgers vectors and possible dislocation reactions are necessary to optimize the fabrication processes and the properties of SiGe materials. In this review a brief overview of the dislocation mechanisms in the SiGe system is given. The method of choice for dislocation characterization is transmission electron microscopy. In particular, the article provides a detailed introduction into large-angle convergent-beam electron diffraction, and gives an overview of different application examples of this method on SiGe structures and related systems.
Collapse
|
6
|
Uprooting defects to enable high-performance III-V optoelectronic devices on silicon. Nat Commun 2019; 10:4322. [PMID: 31541107 PMCID: PMC6754402 DOI: 10.1038/s41467-019-12353-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 08/15/2019] [Indexed: 11/09/2022] Open
Abstract
The monolithic integration of III-V compound semiconductor devices with silicon presents physical and technological challenges, linked to the creation of defects during the deposition process. Herein, a new defect elimination strategy in highly mismatched heteroepitaxy is demonstrated to achieve a ultra-low dislocation density, epi-ready Ge/Si virtual substrate on a wafer scale, using a highly scalable process. Dislocations are eliminated from the epilayer through dislocation-selective electrochemical deep etching followed by thermal annealing, which creates nanovoids that attract dislocations, facilitating their subsequent annihilation. The averaged dislocation density is reduced by over three orders of magnitude, from ~108 cm-2 to a lower-limit of ~104 cm-2 for 1.5 µm thick Ge layer. The optical properties indicate a strong enhancement of luminescence efficiency in GaAs grown on this virtual substrate. Collectively, this work demonstrates the promise for transfer of this technology to industrial-scale production of integrated photonic and optoelectronic devices on Si platforms in a cost-effective way.
Collapse
|
7
|
|
8
|
Meduňa M, Isa F, Jung A, Marzegalli A, Albani M, Isella G, Zweiacker K, Miglio L, von Känel H. Lattice tilt and strain mapped by X-ray scanning nanodiffraction in compositionally graded SiGe/Si microcrystals. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576718001450] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The scanning X-ray nanodiffraction technique is used to reconstruct the three-dimensional distribution of lattice strain and Ge concentration in compositionally graded Si1−xGexmicrocrystals grown epitaxially on Si pillars. The reconstructed crystal shape qualitatively agrees with scanning electron micrographs and the calculated three-dimensional distribution of lattice tilt quantitatively matches finite-element method simulations. The grading of the Ge content obtained from reciprocal-space maps corresponds to the nominal grading of the epitaxial growth recipe. The X-ray measurements confirm strain calculations, according to which the lattice curvature of the microcrystals is dominated by the misfit strain, while the thermal strain contributes negligibly. The nanodiffraction experiments also indicate that the strain in narrow microcrystals on 2 × 2 µm Si pillars is relaxed purely elastically, while in wider microcrystals on 5 × 5 µm Si pillars, plastic relaxation by means of dislocations sets in. This confirms previous work on these structures using transmission electron microscopy and defect etching.
Collapse
|
9
|
Atomic Scale Formation Mechanism of Edge Dislocation Relieving Lattice Strain in a GeSi overlayer on Si(001). Sci Rep 2017; 7:11966. [PMID: 28931841 PMCID: PMC5607354 DOI: 10.1038/s41598-017-12009-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 08/31/2017] [Indexed: 11/19/2022] Open
Abstract
Understanding how edge misfit dislocations (MDs) form in a GeSi/Si(001) film has been a long standing issue. The challenge is to find a mechanism accounting for the presence of these dislocations at the interface since they are not mobile and cannot nucleate at the surface and glide towards the interface. Furthermore, experiments can hardly detect the nucleation and early stages of growth because of the short time scale involved. Here we present the first semi-quantitative atomistic calculation of the formation of edge dislocations in such films. We use a global optimization method and density functional theory calculations, combined with computations using potential energy functions to identify the best mechanisms. We show that those previously suggested are relevant only for a low film strain and we propose a new mechanism which accounts for the formation of edge dislocations at high film strain. In this one, a 60° MD nucleates as a “split” half-loop with two branches gliding on different planes. One branch belongs to the glide plane of a complementary 60° MD and therefore strongly favors the formation of the complementary MD which is immediately combined with the first MD to form an edge MD.
Collapse
|
10
|
Tallaire A, Brinza O, Mille V, William L, Achard J. Reduction of Dislocations in Single Crystal Diamond by Lateral Growth over a Macroscopic Hole. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1604823. [PMID: 28218441 DOI: 10.1002/adma.201604823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/15/2016] [Indexed: 06/06/2023]
Abstract
A low-dislocation diamond is obtained by homoepitaxial chemical vapor deposition on a standard moderate-quality substrate hollowed out by a large square hole. Dislocations are found to propagate vertically and horizontally from the substrate and to terminate at the top surface or at the sides of the hole, thus leaving the central part with a strongly reduced dislocation density.
Collapse
Affiliation(s)
- Alexandre Tallaire
- Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.B. Clément, 93430, Villetaneuse, France
| | - Ovidiu Brinza
- Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.B. Clément, 93430, Villetaneuse, France
| | - Vianney Mille
- Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.B. Clément, 93430, Villetaneuse, France
| | - Ludovic William
- Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.B. Clément, 93430, Villetaneuse, France
| | - Jocelyn Achard
- Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.B. Clément, 93430, Villetaneuse, France
| |
Collapse
|
11
|
Arroyo Rojas Dasilva Y, Kozak R, Erni R, Rossell MD. Structural defects in cubic semiconductors characterized by aberration-corrected scanning transmission electron microscopy. Ultramicroscopy 2016; 176:11-22. [PMID: 27838069 DOI: 10.1016/j.ultramic.2016.09.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/23/2016] [Accepted: 09/25/2016] [Indexed: 11/29/2022]
Abstract
The development of new electro-optical devices and the realization of novel types of transistors require a profound understanding of the structural characteristics of new semiconductor heterostructures. This article provides a concise review about structural defects which occur in semiconductor heterostructures on the basis of micro-patterned Si substrates. In particular, one- and two-dimensional crystal defects are being discussed which are due to the plastic relaxation of epitaxial strain caused by the misfit of crystal lattices. Besides a few selected examples from literature, we treat in particular crystal defects occurring in GaAs/Si, Ge/Si and β-SiC/Si structures which are studied by high-resolution annular dark-field scanning transmission electron microscopy. The relevance of this article is twofold; firstly, it should provide a collection of data which are of help for the identification and characterization of defects in cubic semiconductors by means of atomic-resolution imaging, and secondly, the experimental data shall provide a basis for advancing the understanding of device characteristics with the aid of theoretical modelling by considering the defective nature of strained semiconductor heterostructures.
Collapse
Affiliation(s)
- Yadira Arroyo Rojas Dasilva
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Roksolana Kozak
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Rolf Erni
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Marta D Rossell
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland.
| |
Collapse
|
12
|
Skibitzki O, Capellini G, Yamamoto Y, Zaumseil P, Schubert MA, Schroeder T, Ballabio A, Bergamaschini R, Salvalaglio M, Miglio L, Montalenti F. Reduced-Pressure Chemical Vapor Deposition Growth of Isolated Ge Crystals and Suspended Layers on Micrometric Si Pillars. ACS APPLIED MATERIALS & INTERFACES 2016; 8:26374-26380. [PMID: 27603117 DOI: 10.1021/acsami.6b07694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out in a commercial reduced-pressure chemical vapor deposition reactor, thus extending the "vertical-heteroepitaxy" technique developed by using the peculiar low-energy plasma-enhanced chemical vapor deposition reactor, to widely available epitaxial tools. The growth process was thoroughly analyzed, from the formation of small initial seeds to the final coalescence into a continuous suspended layer, by means of scanning and transmission electron microscopy, X-ray diffraction, and μ-Raman spectroscopy. The preoxidation of the Si pillar sidewalls and the addition of hydrochloric gas in the reactants proved to be key to achieve highly selective Ge growth on the pillars top only, which, in turn, is needed to promote the formation of a continuous Ge layer. Thanks to continuum growth models, we were able to single out the different roles played by thermodynamics and kinetics in the deposition dynamics. We believe that our findings will open the way to the low-cost realization of tens of micrometers thick heteroepitaxial layer (e.g., Ge, SiC, and GaAs) on Si having high crystal quality.
Collapse
Affiliation(s)
| | - Giovanni Capellini
- IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
- Department of Science, Università Roma Tre , Viale G. Marconi 446, Rome I-00146, Italy
| | - Yuji Yamamoto
- IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Peter Zaumseil
- IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | | | - Thomas Schroeder
- IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
- Brandenburgische Technische Universität, Konrad-Zuse-Str. 1, Cottbus 03046, Germany
| | - Andrea Ballabio
- L-NESS and Department of Physics, Politecnico di Milano , Via Anzani 42, Como I-22100, Italy
| | - Roberto Bergamaschini
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via Cozzi 55, Milan I-20125, Italy
| | - Marco Salvalaglio
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via Cozzi 55, Milan I-20125, Italy
| | - Leo Miglio
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via Cozzi 55, Milan I-20125, Italy
| | - Francesco Montalenti
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via Cozzi 55, Milan I-20125, Italy
| |
Collapse
|
13
|
Meduňa M, Falub CV, Isa F, Marzegalli A, Chrastina D, Isella G, Miglio L, Dommann A, von Känel H. Lattice bending in three-dimensional Ge microcrystals studied by X-ray nanodiffraction and modelling. J Appl Crystallogr 2016. [DOI: 10.1107/s1600576716006397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Extending the functionality of ubiquitous Si-based microelectronic devices often requires combining materials with different lattice parameters and thermal expansion coefficients. In this paper, scanning X-ray nanodiffraction is used to map the lattice bending produced by thermal strain relaxation in heteroepitaxial Ge microcrystals of various heights grown on high aspect ratio Si pillars. The local crystal lattice tilt and curvature are obtained from experimental three-dimensional reciprocal space maps and compared with diffraction patterns simulated by means of the finite element method. The simulations are in good agreement with the experimental data for various positions of the focused X-ray beam inside a Ge microcrystal. Both experiment and simulations reveal that the crystal lattice bending induced by thermal strain relaxation vanishes with increasing Ge crystal height.
Collapse
|
14
|
Salvalaglio M, Bergamaschini R, Isa F, Scaccabarozzi A, Isella G, Backofen R, Voigt A, Montalenti F, Capellini G, Schroeder T, von Känel H, Miglio L. Engineered Coalescence by Annealing 3D Ge Microstructures into High-Quality Suspended Layers on Si. ACS APPLIED MATERIALS & INTERFACES 2015; 7:19219-19225. [PMID: 26252761 DOI: 10.1021/acsami.5b05054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The move from dimensional to functional scaling in microelectronics has led to renewed interest toward integration of Ge on Si. In this work, simulation-driven experiments leading to high-quality suspended Ge films on Si pillars are reported. Starting from an array of micrometric Ge crystals, the film is obtained by exploiting their temperature-driven coalescence across nanometric gaps. The merging process is simulated by means of a suitable surface-diffusion model within a phase-field approach. The successful comparison between experimental and simulated data demonstrates that the morphological evolution is driven purely by the lowering of surface-curvature gradients. This allows for fine control over the final morphology to be attained. At fixed annealing time and temperature, perfectly merged films are obtained from Ge crystals grown at low temperature (450 °C), whereas some void regions still persist for crystals grown at higher temperature (500 °C) due to their different initial morphology. The latter condition, however, looks very promising for possible applications. Indeed, scanning tunneling electron microscopy and high-resolution transmission electron microscopy analyses show that, at least during the first stages of merging, the developing film is free from threading dislocations. The present findings, thus, introduce a promising path to integrate Ge layers on Si with a low dislocation density.
Collapse
Affiliation(s)
- Marco Salvalaglio
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via R. Cozzi 55, I-20126, Milano, Italy
| | - Roberto Bergamaschini
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via R. Cozzi 55, I-20126, Milano, Italy
| | - Fabio Isa
- Laboratory for Solid State Physics, ETH Zürich , Otto-Stern-Weg 1, CH-8093, Zürich, Switzerland
| | - Andrea Scaccabarozzi
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via R. Cozzi 55, I-20126, Milano, Italy
| | - Giovanni Isella
- L-NESS and Department of Physics, Politecnico di Milano , Via F. Anzani 42, I-22100, Como, Italy
| | - Rainer Backofen
- Institut für Wissenschaftliches Rechnen, Technische Universität Dresden , Zellescher Weg 12-14, D-01069, Dresden, Germany
| | - Axel Voigt
- Institut für Wissenschaftliches Rechnen, Technische Universität Dresden , Zellescher Weg 12-14, D-01069, Dresden, Germany
| | - Francesco Montalenti
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via R. Cozzi 55, I-20126, Milano, Italy
| | - Giovanni Capellini
- IHP , Im Technologiepark 25, D-15236, Frankfurt (Oder), Germany
- Department of Science, Università Roma Tre , Viale Marconi 446, I-00146, Roma, Italy
| | | | - Hans von Känel
- Laboratory for Solid State Physics, ETH Zürich , Otto-Stern-Weg 1, CH-8093, Zürich, Switzerland
| | - Leo Miglio
- L-NESS and Department of Materials Science, Università di Milano-Bicocca , Via R. Cozzi 55, I-20126, Milano, Italy
| |
Collapse
|
15
|
Groiss H, Glaser M, Marzegalli A, Isa F, Isella G, Miglio L, Schäffler F. Burgers Vector Analysis of Vertical Dislocations in Ge Crystals by Large-Angle Convergent Beam Electron Diffraction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:637-645. [PMID: 25939606 DOI: 10.1017/s1431927615000537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
By transmission electron microscopy with extended Burgers vector analyses, we demonstrate the edge and screw character of vertical dislocations (VDs) in novel SiGe heterostructures. The investigated pillar-shaped Ge epilayers on prepatterned Si(001) substrates are an attempt to avoid the high defect densities of lattice mismatched heteroepitaxy. The Ge pillars are almost completely strain-relaxed and essentially defect-free, except for the rather unexpected VDs. We investigated both pillar-shaped and unstructured Ge epilayers grown either by molecular beam epitaxy or by chemical vapor deposition to derive a general picture of the underlying dislocation mechanisms. For the Burgers vector analysis we used a combination of dark field imaging and large-angle convergent beam electron diffraction (LACBED). With LACBED simulations we identify ideally suited zeroth and second order Laue zone Bragg lines for an unambiguous determination of the three-dimensional Burgers vectors. By analyzing dislocation reactions we confirm the origin of the observed types of VDs, which can be efficiently distinguished by LACBED. The screw type VDs are formed by a reaction of perfect 60° dislocations, whereas the edge types are sessile dislocations that can be formed by cross-slips and climbing processes. The understanding of these origins allows us to suggest strategies to avoid VDs.
Collapse
Affiliation(s)
- Heiko Groiss
- 1Institute of Semiconductor and Solid State Physics,Johannes Kepler University Linz,Altenbergerstr. 69,4040 Linz,Austria
| | - Martin Glaser
- 1Institute of Semiconductor and Solid State Physics,Johannes Kepler University Linz,Altenbergerstr. 69,4040 Linz,Austria
| | - Anna Marzegalli
- 2L-NESS and Department of Materials Science,Università degli Studi di Milano-Bicocca,via Cozzi 53,20125 Milano,Italy
| | - Fabio Isa
- 3L-NESS and Department of Physics,Politecnico di Milano,via Anzani 42,22100 Como,Italy
| | - Giovanni Isella
- 3L-NESS and Department of Physics,Politecnico di Milano,via Anzani 42,22100 Como,Italy
| | - Leo Miglio
- 2L-NESS and Department of Materials Science,Università degli Studi di Milano-Bicocca,via Cozzi 53,20125 Milano,Italy
| | - Friedrich Schäffler
- 1Institute of Semiconductor and Solid State Physics,Johannes Kepler University Linz,Altenbergerstr. 69,4040 Linz,Austria
| |
Collapse
|
16
|
Meduňa M, Falub CV, Isa F, Chrastina D, Kreiliger T, Isella G, von Känel H. Reconstruction of crystal shapes by X-ray nanodiffraction from three-dimensional superlattices. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714023772] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Quantitative nondestructive imaging of structural properties of semiconductor layer stacks at the nanoscale is essential for tailoring the device characteristics of many low-dimensional quantum structures, such as ultrafast transistors, solid state lasers and detectors. Here it is shown that scanning nanodiffraction of synchrotron X-ray radiation can unravel the three-dimensional structure of epitaxial crystals containing a periodic superlattice underneath their faceted surface. By mapping reciprocal space in all three dimensions, the superlattice period is determined across the various crystal facets and the very high crystalline quality of the structures is demonstrated. It is shown that the presence of the superlattice allows the reconstruction of the crystal shape without the need of any structural model.
Collapse
|
17
|
Falub CV, Meduňa M, Chrastina D, Isa F, Marzegalli A, Kreiliger T, Taboada AG, Isella G, Miglio L, Dommann A, von Känel H. Perfect crystals grown from imperfect interfaces. Sci Rep 2013; 3:2276. [PMID: 23880632 PMCID: PMC3721082 DOI: 10.1038/srep02276] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/09/2013] [Indexed: 11/30/2022] Open
Abstract
The fabrication of advanced devices increasingly requires materials with different properties to be combined in the form of monolithic heterostructures. In practice this means growing epitaxial semiconductor layers on substrates often greatly differing in lattice parameters and thermal expansion coefficients. With increasing layer thickness the relaxation of misfit and thermal strains may cause dislocations, substrate bowing and even layer cracking. Minimizing these drawbacks is therefore essential for heterostructures based on thick layers to be of any use for device fabrication. Here we prove by scanning X-ray nanodiffraction that mismatched Ge crystals epitaxially grown on deeply patterned Si substrates evolve into perfect structures away from the heavily dislocated interface. We show that relaxing thermal and misfit strains result just in lattice bending and tiny crystal tilts. We may thus expect a new concept in which continuous layers are replaced by quasi-continuous crystal arrays to lead to dramatically improved physical properties.
Collapse
Affiliation(s)
- Claudiu V Falub
- Laboratory for Solid State Physics, ETH-Zürich, Schafmattstrasse 16, 8093 Zürich, Switzerland.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|