Rheed Study of Strain Relaxation in Epitaxial Cds and Sn Overlayers

1990 ◽  
Vol 208 ◽  
Author(s):  
David W. Niles ◽  
Hartmut Höchst
Keyword(s):  
Film Thickness ◽  
Lattice Constant ◽  
Reasonable Agreement ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Epitaxial Films ◽  
Mechanical Equilibrium ◽  
Lattice Constants ◽  
Critical Film Thickness ◽  
Experimental Findings

ABSTRACTThe relaxation of strain in epitaxial overlayers is studied through an analysis of RHEED patterns. From the separation of the RHEED reflections, we determine the in-plane lattice constants for α-Sn/Cd0.8Zn0.2Te(100), CdS/GaAs(100), and CdS/CdTe(100) heterostructures. The discussion focuses on the critical thickness of the overlayers and the relaxation of the inplane lattice constant (a∥) of epitaxial films which exceed the critical thickness. Predictions based on Matthews and Blakeslee's mechanical equilibrium theory show reasonable agreement with our experimental findings, indicating that the metastability of the epitaxial overlayers does not cause a significant reduction in the critical film thickness.

Stress Driven Patterning of Epitaxial Films

1993 ◽  
Vol 318 ◽  
Author(s):  
Michael A. Grinfeld
Keyword(s):  
Surface Energy ◽  
Surface Morphology ◽  
Film Thickness ◽  
Critical Thickness ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Two Dimensional ◽  
Dimensional Lattice ◽  
One Dimensional ◽  
Periodic Spacing

ABSTRACTWe study possible morphologies of epitaxial films atop attractive substrates appearing as a result of competition of misfit stresses, van der Waals forces and surface energy. Corresponding formula for the critical thickness of the dislocation-free Stranski-Krastanov pattern is established for the isotropic deformable films and substrates. If the film thickness exceeds the critical magnitude the layer-by-layer pattern switches to islanding. At the first stage the islands have a shape of striae (i.e. long parallel trenches with periodic spacing). We discuss also i)the circumstances in which surface morphology of the film corresponds to a two-dimensional superlattice of islands rather than a one dimensional lattice of striae and ii)the influence of a buffer inter-layer.

VARIATION OF IN-PLANE LATTICE CONSTANT OF Si/Ge/Si HETEROSTRUCTURES WITH Ge QUANTUM DOTS

2007 ◽  
Vol 06 (03n04) ◽  
pp. 297-299 ◽  
Author(s):  
ALEXANDER NIKIFOROV ◽  
VLADIMIR ULYANOV ◽  
ROMAN SHAIDUK ◽  
SERGEY TEYS ◽  
ANTON GUTAKOVSKY ◽  
...  
Keyword(s):  
Experimental Data ◽  
Quantum Dots ◽  
Lattice Constant ◽  
Film Growth ◽  
Strain Relaxation ◽  
Silicon Film ◽  
Lattice Constants ◽  
Plane Lattice ◽  
Si Films ◽  
Elastic Strains

Experimental data are presented on variations of the in-plane lattice constant of Ge and Si films in the course of the MBE film growth on the silicon (100) surface. The in-plane lattice constant of the silicon film is shown to alter as the film grows; the changes reflect the process of relaxation of elastic strains that result from the misfit of the germanium and silicon lattice constants. Due to the presence of germanium islands, a considerably thicker silicon film is required to provide the strain relaxation. The dependence of distortion penetration depth to the silicon film on the effective germanium film thickness is obtained. TEM studies indicate the vertical ordering of the germanium island layers when the thickness of the Si layer in between Ge layers is not sufficient to provide the full strain relaxation.

The Stress Driven Islands Formation in Epitaxial Films and Solid HE4 Films.

1992 ◽  
Vol 280 ◽  
Author(s):  
Michael A. Grinfeld
Keyword(s):  
Surface Energy ◽  
Shear Modulus ◽  
Film Thickness ◽  
Epitaxial Films ◽  
Morphological Instability ◽  
Thin Solid Films ◽  
Solid Films ◽  
Mismatch Stress ◽  
Critical Film Thickness ◽  
Morphological Patterns

ABSTRACTWe discuss the static and quasi-static problems appearing in the theory of morphological instability of interfaces. The approach has allowed to predict the corrugations in He4 films and to explain the dislocation-free Stranski-Krastanow pattern of epitaxial growth of thin solid films with the critical film thickness H = σμ/τ2 (σ is a surface energy, μ- the shear modulus, and τ - the mismatch stress). In this paper we discuss possible morphological patterns of corrugations and their changes which appear in result of the stress driven “rearrangement” destabilization of originally flat interfaces.

Measuring the critical thickness of thin metalorganic precursor films

1999 ◽  
Vol 14 (6) ◽  
pp. 2364-2368 ◽  
Author(s):  
Ryan K. Roeder ◽  
Elliott B. Slamovich
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Critical Thickness ◽  
Sol Gel ◽  
Optical Microscope ◽  
Precursor Film ◽  
Ceramic Thin Films ◽  
Color Fringe ◽  
Metalorganic Decomposition ◽  
Critical Film Thickness

Successful application of sol-gel, metalorganic decomposition, or hydrothermal routes to ceramic thin films depends on the mechanical integrity of the precursor film. Above a critical thickness, a precursor film will crack or decohere from the substrate during drying. The cracking and thickness of thin metalorganic precursor films were simultaneously observed during drying using a standard optical microscope. Isochromatic color fringes produced by interference of reflected white light were used to monitor film thickness. The critical film thickness was determined by the color fringe corresponding to the thickness at which propagating cracks terminated. As a demonstration of the technique, the critical thickness of titanium di(isopropoxide) bis(ethyl acetoacetate) films was measured, showing increased critical thickness with the addition of small amounts of an elastomeric polymer.

Island and pit formation during growth and annealing of InGaAs/GaAs films

2001 ◽  
Vol 696 ◽  
Author(s):  
A. Riposan ◽  
G.K.M. Martin ◽  
M. Bouville ◽  
M. L. Falk ◽  
J. Mirecki Millunchick
Keyword(s):  
Surface Morphology ◽  
Film Thickness ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Growth Conditions ◽  
Wetting Layer ◽  
Island Nucleation ◽  
Pit Formation ◽  
Gaas Films ◽  
The Stability

AbstractThe surface morphology near the onset of 3D roughening of In0.27Ga0.73As/GaAs films was investigated for films both immediately after growth and after annealing. As expected, 3D island nucleation coincides with the onset of strain relaxation at a critical thickness hc. As strain relaxation continues, pits form adjacent to 3D islands. The onset of the pit formation depends on the growth conditions, including the growth temperature and As overpressure, and the areal coverage of 3D islands. On average, pits form only after the area coverage of islands reaches ~50%. The islands and pits coalesce into ripple arrays as the film thickness increases. Films below and above the critical thickness for 3D roughening were annealed to study the stability of islands and pits. For films with thicknesses below hc, initially smooth surfaces evolve into islanded morphologies upon annealing. For films grown above hc which have both islands and pits on the surface, both islands and pits grow and coalesce during annealing. These results suggest that pit formation is favored, but it requires a minimum island coverage and/or wetting layer thickness in order to nucleate.

Mechanism of in-plane texture development by ion-beam-assisted deposition

1999 ◽  
Vol 14 (6) ◽  
pp. 2524-2532 ◽  
Author(s):  
H. Ji ◽  
G. S. Was
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Critical Thickness ◽  
Ion Beam ◽  
Texture Development ◽  
Preferential Growth ◽  
Ion Energy ◽  
Nucleation Stage ◽  
Ion Beam Assisted Deposition ◽  
Critical Film Thickness

The objective of this work was to determine the mechanism of in-plane texture development in films made by ion-beam-assisted deposition (IBAD). Both in-plane texture and surface roughness were studied as functions of film thickness. A phenomenological growth model based on the preferential growth of aligned grains due to channeling was proposed, linking the surface roughness evolution and texture development. Good correlation was found between the measured roughness and the model prediction, as well as between the roughness evolution and the in-plane texture development. A critical thickness was introduced at which in-plane texture is completed. Both surface roughness and texture results gave a critical film thickness of 114–250 nm for an ion energy of 1000 eV and an R ratio of 0.4. This range of critical film thickness was far beyond the nucleation stage, providing evidence that the development of in-plane texture in IBAD Nb films was growth-controlled.

Rotating 1-D magnetic photonic crystal balls with a tunable lattice constant

Nanoscale ◽  
2017 ◽  
Vol 9 (27) ◽  
pp. 9548-9555 ◽  
Author(s):  
Wei Luo ◽  
Jindan Yan ◽  
Yali Tan ◽  
Huiru Ma ◽  
Jianguo Guan
Keyword(s):  
Magnetic Field ◽  
Photonic Crystal ◽  
Lattice Constant ◽  
Lattice Constants ◽  
Magnetic Photonic Crystal

1-D magnetic photonic crystal balls with uniform colors can be smoothly rotated by magnetic field even when the lattice constants change with stimuli.

Low-Temperature Epitaxial Growth of IN-Situ HeavilY B-Doped Si1-xGex, Films Using Ultraclean LPCVD

1998 ◽  
Vol 533 ◽  
Author(s):  
A. Morrya ◽  
M. Sakuraba ◽  
T. Matsuura ◽  
J. Murota ◽  
I. Kawashima ◽  
...  
Keyword(s):  
Low Temperature ◽  
Partial Pressure ◽  
Epitaxial Growth ◽  
Lattice Constant ◽  
Deposition Rate ◽  
Epitaxial Films ◽  
Similar Degree ◽  
Gas Mixture ◽  
Heavy Doping

AbstractIn-situ heavy doping of B into Si1-xGex epitaxial films on the Si(100) substrate have been investigated at 550°C in a SiH4(6.0Pa)-GeH4(0.1−6.0Pa)-B2H6(1.25 ×10−5−3.75 × 10−2Pa)-H2(17–24Pa) gas mixture by using an ultraclean hot-wall low-pressure CVD system. The deposition rate increased with increasing GeH4 partial pressure, and it decreased with increasing B2H6 partial pressure only at the higher GeH4 partial pressure. As the B2H6 partial pressure increased, the Ge fraction scarcely changed although the lattice constant of the film decreased. These characteristics can be explained by the suppression of both the SiH4 and GeH4 adsorption/reactions in a similar degree due to B2H6 adsorption on the Si-Ge and/or Ge-Ge bond sites. The B concentration in the film increased proportionally up to 1022cm3 with increasing B2H6 partial pressure.

scholarly journals Влияние напряжения смещения и скорости осаждения на структуру и коэрцитивность пленок NiFe

2020 ◽  
Vol 62 (12) ◽  
pp. 2174
Author(s):  
А.С. Джумалиев ◽  
C.Л. Высоцкий ◽  
В.К. Сахаров
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Film Thickness ◽  
Deposition Rate ◽  
Entire Range ◽  
Soft Magnetic Properties ◽  
Supercritical State ◽  
Dc Magnetron Sputtering ◽  
Soft Magnetic ◽  
Critical Film Thickness

Influence of the bias voltage Ub and the deposition rate  on the structure, grain size D, and coercivity Hc of NiFe films with the thickness d from 30 to 980 nm, grown onto Si / SiO2 substrates by DC magnetron sputtering, was studied. In the case Ub = 0, the decrease of  from ≈ nm/min to ≈ 7 nm/min is accompanied by the increase of the critical film thickness dcr from dcr ≈ 220 nm to dcr ≈ 270 nm. In this case, Hc in the films with d < dcr is characterized by the dependence Hc ~ D6 and varies from ~ 1 to ~ 20 Oe. In the case of Ub = -100 V, the effect of the deposition rate on the coercivity is much more noticeable. At ν = 7 and 14 nm / min, the films demonstrate soft magnetic properties (Нс ≈ 0.15 - 1.4 Oe) and the absence of dcr for the entire range of studied thicknesses. The films obtained at ν = 21 and 27 nm / min turn into the “supercritical” state at d ≥ dcr ≈ 520 nm, and, in the region d < dcr, they are characterized by the dependence Hc ~ D3 and by the increase of coercivity from ~ 0.35 to ~ 10 Oe.

Comparison of the Fracture Behavior of Brittle ILD Films used in the BEOL in Dry and Wet Environment using Nanoindentation

2006 ◽  
Vol 914 ◽  
Author(s):  
Eva Simonyi ◽  
Michael Lane ◽  
Erik Liniger ◽  
Alfred Grill
Keyword(s):  
Fracture Toughness ◽  
Film Thickness ◽  
Manufacturing Process ◽  
Fracture Behavior ◽  
Imaging Methods ◽  
Afm Imaging ◽  
Critical Film Thickness ◽  
Low K

AbstractDuring the manufacturing process of the BEOL the low-k brittle ILD dielectrics are exposed to wet environments. These environments could and do affect the films fracture toughness, the so called critical film thickness, above which spontaneous cracking occurs. Nanoindentation combined with AFM imaging methods allow to study these phenomena.

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