Lattice Parameter and Density in Germanium-Silicon Alloys1
01 Oct 1964-The Journal of Physical Chemistry (American Chemical Society)-Vol. 68, Iss: 10, pp 3021-3027
About: This article is published in The Journal of Physical Chemistry.The article was published on 1964-10-01. It has received 680 citations till now. The article focuses on the topics: Hexagonal lattice & Reciprocal lattice.
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TL;DR: In this paper, the authors present the current state of experimental data for basic parameters such as point-defect diffusivities and equilibrium concentrations and address a number of questions regarding the mechanisms of dopant diffusion.
Abstract: Diffusion in silicon of elements from columns III and V of the Periodic Table is reviewed in theory and experiment. The emphasis is on the interactions of these substitutional dopants with point defects (vacancies and interstitials) as part of their diffusion mechanisms. The goal of this paper is to unify available experimental observations within the framework of a set of physical models that can be utilized in computer simulations to predict diffusion processes in silicon. The authors assess the present state of experimental data for basic parameters such as point-defect diffusivities and equilibrium concentrations and address a number of questions regarding the mechanisms of dopant diffusion. They offer illustrative examples of ways that diffusion may be modeled in one and two dimensions by solving continuity equations for point defects and dopants. Outstanding questions and inadequacies in existing formulations are identified by comparing computer simulations with experimental results. A summary of the progress made in this field in recent years and of directions future research may take is presented.
1,155 citations
TL;DR: In this paper, the lattice parameter of high-purity silicon is measured as a function of temperature between 300 and 1500 K, and the linear thermal expansion coefficient is accurately determined.
Abstract: The lattice parameter of high‐purity silicon is measured as a function of temperature between 300 and 1500 K, and the linear thermal expansion coefficient is accurately determined. Precise measurements are made by the high‐temperature attachment for Bond’s x‐ray method to a few parts per million. It is found that the temperature dependence of the linear thermal expansion coefficient α(t) is empirically given by α(t)=(3.725{1−exp[−5.88×10−3{(t−124)} +5.548×10−4t)×10−6 (K−1), where t is the absolute temperature ranging from 120 to 1500 K. It is shown that the lattice parameter in the above temperature range can be calculated using α(t) and the lattice parameter at 273.2 K (0.5430741 nm). Measured values of the lattice parameter and the thermal expansion coefficient for high‐purity float‐zoned (100 kΩ cm) and Czochralski‐grown (30 Ω cm) single crystals are uniformly distributed within ±1×10−5 nm and ±2×10−7 K−1 with respect to the values obtained from the above empirical formula.
1,089 citations
TL;DR: In this article, the structural and electronic properties of lattice-mismatched Si/SiGe heterostructures are discussed in terms of scattering mechanisms and experimental results, and an assessment of the possible role of such heterodevices in future microelectronic circuits is given.
Abstract: Silicon-based heterostructures have come a long way from the discovery of strain as a new and essential parameter for band structure engineering to the present state of electron and hole mobilities, which surpass those achieved in the traditional material combination by more than an order of magnitude and are rapidly approaching the best III - V heteromaterials. It is the purpose of this article to report on the most recent developments, and the performance level achieved to date in this material system, in a concise and critical manner. The first part of this review is concerned with the structural and electronic properties of the lattice-mismatched Si/SiGe heterostructure. Emphases are put on the effects of strain both on the band structure and on the band offsets, as well as on means to actually control the strain in a stack of heteroepitaxial layers. The second part is dedicated to the transport properties of low-dimensional carrier systems in Si/SiGe and Ge/SiGe heterostructures. The prospects and limitations of the different layer concepts are discussed in terms of scattering mechanisms and experimental results. This part also reviews the most recent magneto-transport experiments on quantum wires and quantum point contacts, which became possible by the enhanced mean free paths in these materials. The third part covers the device aspects of these high-mobility materials, which is of special interest, because silicon-based heterostructures can significantly enhance the performance level of contemporary Si devices without sacrificing the essential compatibility with standard Si technologies. The recent achievements in this application-driven research field, but also the foreseeable problems and limitations, are discussed, and an assessment of the possible role of such heterodevices in future microelectronic circuits is given.
752 citations
TL;DR: In this article, the thermal expansion coefficients of high-purity AlN, sapphire, and silicon were calculated from the data obtained with precision high-temperature x-ray lattice parameter measurements.
Abstract: Thermal expansion coefficients of high‐purity AlN, sapphire, and silicon were calculated from the data obtained with precision high‐temperature x‐ray lattice parameter measurements The mean thermal expansion coefficients obtained in the range 20–800°C are α⊥ = 53 × 10−6/°C and α∥ = 42 × 10−6/°C for AlN, α⊥ = 73 × 10−6/°C and α∥ = 81 × 10−6/°C for α‐Al2O3, and α = 36 × 10−6/°C for Si
470 citations
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TL;DR: In this article, a review of Si/Ge nanostructures that have been synthesized by self-assembling and self-ordering during heteroepitaxy of \mbox{silicon-germanium} alloys on single-crystal silicon substrates is given.
Abstract: A review is given on the formation mechanisms and the properties of Si/Ge nanostructures that have been synthesized by self-assembling and self-ordering during heteroepitaxy of \mbox{silicon-germanium} alloys on single-crystal silicon substrates. The properties of electronic subbands in smooth strained Si/SiGe quantum well structures are presented as a basis for characterizing coherent Si/Ge nanostructures with free motion of carriers in a reduced number of dimensions. The low-dimensional band structure of valence band states confined in strained Si/Ge and Si/SiGe nanostructures is analysed by optical and electrical spectroscopy. The nanostructures presented were fabricated by self-assembly induced by elastic strain relaxation without applying any patterning technique. Misfit lattice strain of SiGe material deposited on Si substrates can relax by bunching of atomic surface steps with SiGe agglomeration at the step edges or by nucleation of Ge-rich islands in the Stranski-Krastanow growth mode. The size, density and composition of such Si/Ge nanostructures representing quantum wires and dots, respectively, can be tuned in a wide range by the growth parameters. Local strain fields extending into the Si host influence the nucleation and the lateral arrangement of nanostructures in subsequent layers and can be applied for self-ordering of nanostructures in the vertical as well as the lateral direction. Interband and intra-valence-band photocurrent, absorption and photoluminescence spectroscopy as well as C-V and admittance measurements reveal a consistent view of the band structure in Si/Ge quantum dot structures. This is in good agreement with model calculations based on band offsets, deformation potentials and effective electron masses known from earlier studies of Si/SiGe quantum well structures. The effective valence band offsets of hole states within Si/Ge nanostructures reach about 400?meV. Typical quantization energies of about 40?meV due to lateral confinement and Coulomb charging energies up to about 15?meV were observed for holes confined in 20?nm sized Si/Ge dots. Future applications of Si/Ge nanostructures such as photodetectors with improved performance or novel functionality are discussed.
428 citations