Complex behaviour of vacancy point-defects in SrRuO3 thin films

2015 ◽  
Vol 17 (2) ◽  
pp. 1060-1069 ◽  
Author(s):  
Henning Schraknepper ◽  
Christoph Bäumer ◽  
Regina Dittmann ◽  
Roger A. De Souza
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Point Defect ◽  
Point Defects ◽  
Morphological Changes ◽  
Time Dependent ◽  
Complex Behaviour ◽  
Complex Time ◽  
Cation Sublattices ◽  
Diffusion Behaviour

Metastable point-defect concentrations on both anion and cation sublattices give rise to complex time-dependent diffusion behaviour and compositional and morphological changes in thin-film SrRuO3.

Microscopic Properties of Thin Films: Learning About Point Defects

MRS Bulletin ◽  
1992 ◽  
Vol 17 (12) ◽  
pp. 24-32 ◽  
Author(s):  
A. Ourmazd ◽  
M. Scheffler ◽  
M. Heinemann ◽  
J-L. Rouviere
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Point Defect ◽  
Point Defects ◽  
Strain Relaxation ◽  
Extended Defects ◽  
Electron Microscopic ◽  
Diffusion In Solids ◽  
Interfacial Roughness ◽  
Microscopic Studies

Microscopic properties of thin films are often strongly influenced by departures from “perfection.” These can take the form of extended defects such as dislocations, interfacial roughness, or point defects. Direct imaging of extended defects was one of the early contributions of electron microscopy to solid-state science. Since then, the role of extended defects in controlling the fabrication and properties of thin films has been extensively studied and reviewed. Recently, in-situ observation of strain relaxation in thin-film structures has increased our understanding of dislocation kinetics and its effect on properties of thin films.In this article, we focus on electron microscopic studies of interfacial roughness, the effect of processing on thin films, and the role and properties of intrinsic point defects in solids. Concurrent development of sophisticated theoretical and experimental approaches has substantially facilitated the investigation of point-defect properties. Here, we illustrate how results from theory and experiment can be combined to form a detailed picture of point-defect diffusion in solids, and highlight areas needing increased attention. Microscopic properties of thin films cannot be covered in a single review. For this reason, and because fabrication of semiconducting thin films has reached unprecedented levels of sophistication, we illustrate this article with references to semiconducting materials.Our main conclusions can be summarized as follows, (a) Thin films of the highest quality are bounded by interfaces that are microscopically rough. Moreover, thin-film interfaces contain roughness on many length scales, each affecting a subset of the physical properties of interest.

scholarly journals Substrate Induced Polymorphism in Organic Thin Films

2014 ◽  
Vol 70 (a1) ◽  
pp. C728-C728
Author(s):  
Basab Chattopadhyay ◽  
Yves Geerts
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Liquid Crystal ◽  
Charge Transport ◽  
Field Effect Transistors ◽  
Crystal Packing ◽  
Morphological Changes ◽  
Solid Substrate ◽  
Experimental Proof ◽  
Discotic Liquid Crystal

The presence of substrate induced polymorphic phases in thin films is an intriguing phenomenon with the physical and chemical factors responsible for its formation are not yet clearly understood. In particular, this is really crucial in the field of organic electronics, where the charge-transport properties are highly dependent on crystal packing, especially for organic field-effect transistors where charge transport occurs at the interface between the organic semiconductor and the dielectric. In pharmaceutical sector, thin film drug delivery is the new emerging alternative to traditional tablets and oral suspensions. The need to identify and control polymorphism induced by the substrate is thus very crucial. In this presentation, we report the structure and morphological changes associated with a substrate induced polymorphic phases in a discotic liquid crystal and a rod shaped DPP-thiophene-based molecule [1, 2]. The bulk compound and the thin films are characterized by a combination of various X-ray diffraction methods to investigate the structural properties. Atomic force microscopy and polarized optical microscopy are used to determine the thin film morphologies. This is the first experimental proof of presence of a substrate induced phase in discotic liquid crystal showcasing an unique example where the 2-D liquid crystalline phase converts to a 3-D crystal plastic phase due to nucleation caused by the solid substrate over a time scale of a month or longer. The presentation also highlights the importance of polymorphism in DPP-thiophene-based material and the specific organization that could arise from the interaction with the substrate depending on the growing conditions. Here the exact structural and the spectroscopic signatures of different polymorphic forms in bulk and in thin films could be identified. These are clearly factors to consider to induce the formation of a particular polymorph and to help to design deposition methodologies.

scholarly journals Micromagnetics of curved thin films

2020 ◽  
Vol 71 (4) ◽  
Author(s):  
Giovanni Di Fratta
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Energy Functional ◽  
Time Dependent ◽  
Stationary Case ◽  
Demagnetizing Field ◽  
Dependent Case ◽  
Compact Surfaces

Abstract In this paper, we aim at a reduced 2d-model describing the observable states of the magnetization in curved thin films. Under some technical assumptions on the geometry of the thin-film, it is well-known that the demagnetizing field behaves like the projection of the magnetization on the normal to the thin film. We remove these assumptions and show that the result holds for a broader class of surfaces; in particular, for compact surfaces. We treat both the stationary case, governed by the micromagnetic energy functional, and the time-dependent case driven by the Landau–Lifshitz–Gilbert equation.

Optical Birefringence to Determine Morphological Changes in Low-K Thin Film CVD Polymers

1998 ◽  
Vol 511 ◽  
Author(s):  
Jay J. Senkevich ◽  
Viktor Simkovic ◽  
Seshu B. Desu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Stability ◽  
Dielectric Constant ◽  
Film Thickness ◽  
Thermal History ◽  
Deposition Temperature ◽  
Morphological Changes ◽  
High Thermal Stability ◽  
Optical Birefringence

ABSTRACTA great interest exists to reduce power consumption, cross-talk, and RC-delay in ULSI devices by replacing SiO2(k=3.9−4.3) with a polymeric material (k<3.0). Unlike SiO2, polymeric thin films exhibit a complex morphology which varies with the polymer's thermal history, deposition temperature, and film thickness. Since the morphology of the polymer thin film ultimately affects its properties such as its dielectric constant, methods need to be developed to understand the morphological changes in polymer thin films. Further, the polymer thin films must exhibit a high thermal stability due to the relatively high back-end-of-line (BEOL) processing temperature. The polymers which exhibit high thermal stability often contain a mainchain benzene ring. Since benzene has a high anisotropic molecular polarizability, optical birefringence can be used to monitor the polymer chain conformation as a function of the polymer's thermal history, thickness or deposition conditions. Poly(p-xylylene) and poly(tetraflouro-p-xylylene) are shown to have a large negative birefringence, increasing until polymer decomposition. Poly(p-xylylene) becomes increasingly more negatively birefringent after a crystallographic phase change at 220°C. A high negative birefringence results in a large in-plane capacitance, negatively impacting the polymers potential benefit. owever, poly(chlorop-xylylene) and poly(dichloro-p-xylylene) exhibit positive birefringence, which increases until their crystalline melting points at ∼290°C and ∼380°C and thereafter decreases due to film disruption. Conclusions will be drawn based on this positive birefringence for the future molecular design of CVD polymers to decrease their in-plane dielectric constant. Urther poly(chloro-p-xylylene) and poly(p-xylylene) are investigated as a function of deposition temperature and film thickness.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

1991 ◽  
Vol 49 ◽  
pp. 1080-1081
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Growth ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Ion Milling ◽  
Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

Detection of a point defect in a silicon single crystal by high-resolution TEM

1995 ◽  
Vol 53 ◽  
pp. 466-467
Author(s):  
M. Awaji
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Point Defect ◽  
Point Defects ◽  
Noise Level ◽  
Dark Field ◽  
Silicon Single Crystal ◽  
High Resolution Image ◽  
Dark Field Imaging ◽  
Field Imaging

It is necessary to improve the resolution, brightness and signal-to-noise ratio(s/n) for the detection and identification of point defects in crystals. In order to observe point defects, multi-beam dark-field imaging is one of the useful methods. Though this method can improve resolution and brightness compared with dark-field imaging by diffuse scattering, the problem of s/n still exists. In order to improve the exposure time due to the low intensity of the dark-field image and the low resolution, we discuss in this paper the bright-field high-resolution image and the corresponding subtracted image with reference to a changing noise level, and examine the possibility for in-situ observation, identification and detection of the movement of a point defect produced in the early stage of damage process by high energy electron bombardment.The high-resolution image contrast of a silicon single crystal in the [10] orientation containing a triple divacancy cluster is calculated using the Cowley-Moodie dynamical theory and for a changing gaussian noise level. This divacancy model was deduced from experimental results obtained by electron spin resonance. The calculation condition was for the lMeV Berkeley ARM operated at 800KeV.

Scanning-probe microscope analysis of optical thin films: A new analytical tool in a manufacturing environment

1994 ◽  
Vol 52 ◽  
pp. 1068-1069
Author(s):  
S. P. Sapers ◽  
R. Clark ◽  
P. Somerville
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Control ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
List Type ◽  
Manufacturing Environment ◽  
Physical Measurements ◽  
Probe Microscope

OCLI is a leading manufacturer of thin films for optical and thermal control applications. The determination of thin film and substrate topography can be a powerful way to obtain information for deposition process design and control, and about the final thin film device properties. At OCLI we use a scanning probe microscope (SPM) in the analytical lab to obtain qualitative and quantitative data about thin film and substrate surfaces for applications in production and research and development. This manufacturing environment requires a rapid response, and a large degree of flexibility, which poses special challenges for this emerging technology. The types of information the SPM provides can be broken into three categories:(1)Imaging of surface topography for visualization purposes, especially for samples that are not SEM compatible due to size or material constraints;(2)Examination of sample surface features to make physical measurements such as surface roughness, lateral feature spacing, grain size, and surface area;(3)Determination of physical properties such as surface compliance, i.e. “hardness”, surface frictional forces, surface electrical properties.

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