Thermal Stability of Thin Virtual Substrates for High Performance Devices

2006 ◽  
Vol 913 ◽  
Author(s):  
Sarah H Olsen ◽  
Steve J Bull ◽  
Peter Dobrosz ◽  
Enrique Escobedo-Cousin ◽  
Rimoon Agaiby ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Raman Spectroscopy ◽  
Layer Thickness ◽  
Critical Thickness ◽  
Great Promise ◽  
Initial Growth ◽  
Strained Si ◽  
Strained Layers ◽  
Wide Range ◽  
The Impact

AbstractDetailed investigations of strain generation and relaxation in Si films grown on thin Si0.78Ge0.22 virtual substrates using Raman spectroscopy are presented. Good virtual substrate relaxation (>90%) is achieved by incorporating C during the initial growth stage. The robustness of the strained layers to relaxation is studied following high temperature rapid thermal annealing typical of CMOS processing (800-1050 °C). The impact of strained layer thickness on thermal stability is also investigated. Strain in layers below the critical thickness did not relax following any thermal treatments. However for layers above the critical thickness the annealing temperature at which the onset of strain relaxation occurred appeared to decrease with increasing layer thickness. Strain in Si layers grown on thin and thick virtual substrates having identical Ge composition and epilayer thickness has been compared. Relaxation through the introduction of defects has been assessed through preferential defect etching in order to verify the trends observed. Raman signals have been analysed by calibrated deconvolution and curve-fitting of the spectra peaks. Raman spectroscopy has also been used to study epitaxial layer thickness and the impact of Ge out-diffusion during processing. Improved device performance and reduced self-heating effects are demonstrated in thin virtual substrate devices when fabricated using strained layers below the critical thickness. The results suggest that thin virtual substrates offer great promise for enhancing the performance of a wide range of strained Si devices.

ARSENIC-INDUCED DOWNSHIFT OF RAMAN BAND POSITIONS FOR PYRITE

2020 ◽  
Vol 115 (7) ◽  
pp. 1589-1600
Author(s):  
Qiaoqiao Zhu ◽  
Nigel J. Cook ◽  
Guiqing Xie ◽  
Benjamin P. Wade ◽  
Cristiana L. Ciobanu
Keyword(s):  
Raman Spectroscopy ◽  
Environmental Science ◽  
Raman Band ◽  
Eastern China ◽  
Chemical Properties ◽  
Minor Element ◽  
Minor Elements ◽  
Band Position ◽  
Wide Range ◽  
The Impact

Abstract Pyrite commonly incorporates a wide range of trace and minor elements, which in turn may modify some of the mineral’s physical and chemical properties. Published band position data for the Raman spectra of pyrite show a wide variation, and the relationship between band position and the trace/minor element incorporation in pyrite is poorly constrained until now. This prompted a case study on pyrite with varying As content from the Shizilishan Sr-(Pb-Zn) deposit, eastern China, combining electron probe microanalysis with Raman spectroscopy. Results show a significant correlation, with a major downshift (~10 cm–1) of the positions of all three Raman bands with increase of As content from below 0.05 to 4.89 wt % in pyrite. This phenomenon is attributed to increased bond lengths and local distortions within an expanded pyrite crystal structure. Results highlight the potential that Raman spectroscopy offers to estimate the contents of trace/minor elements—especially As—in pyrite. Given that substitution of As into pyrite often facilitates co-incorporation of both economically useful (Au) and environmentally significant elements (Hg and Tl), Raman methodology could provide valuable, rapid assessment of pyrite chemistry in both gold deposit exploration and environmental science, although the impact of laser heating and mechanical polishing needs to be avoided or effectively reduced. Raman spectroscopy may also find a valuable future role within semiautomated multispectral analytical platforms that can generate close- to-real-time geologic information on freshly drilled core directly at the drill site or in outcrop.

A general consideration of incident impact energy accumulation in molecular dynamics thin film simulations—a new approach using thermal control layer marching algorithms

2005 ◽  
Vol 461 (2064) ◽  
pp. 3977-3998 ◽  
Author(s):  
Hong-Chang Lin ◽  
Jee-Gong Chang ◽  
Shin-Pon Ju ◽  
Chi-Chuan Hwang
Keyword(s):  
Thin Film ◽  
Layer Thickness ◽  
Reaction Layer ◽  
Incident Energy ◽  
Thermal Control ◽  
Computational Effort ◽  
Energy Accumulation ◽  
Wide Range ◽  
The Impact ◽  
Control Layer

This paper investigates several highly accurate algorithms which can be used to calculate the morphology in a wide range of thin film process simulations, and which require minimum computational effort. Three different algorithms are considered, namely the kinetic energy corrector (KEC) algorithm, the thermal control layer marching (TLM) algorithm, and the thermal control layer marching algorithm with an incorporated KEC function (TLMC). A common characteristic of these algorithms is that they all address the recovery of the impact incident energy within the free reaction layer. However, they differ in their treatment of the thermal control layer. The TLM and TLMC algorithms consider this layer to be moveable, whereas the KEC algorithm regards it as being fixed. The advantage of employing a moveable thermal control layer is that the computational effort required to carry out simulation is reduced since the atoms lying below this layer are excluded. The relative accuracy and efficiency of the proposed algorithms are evaluated by considering their use in the simulation of the trench-filling problem associated with the damascene process. The results of the present investigation indicate that the TLM algorithm has the ability to provide an accurate morphology calculation for low and medium energy incident atoms. However, for higher incident energy impacts, the TLMC algorithm is found to be a more appropriate choice because the incorporated energy corrector function is required to remove the higher energy accumulation which occurs within the deposited atoms. Furthermore, for all three algorithms, it is noted that a suitable specification of the free reaction layer thickness is essential in determining the accuracy and efficiency of the simulation. Finally, this paper discusses the relationship between the energy absorption rate and the thickness of the free reaction layer, and presents the optimal free reaction layer thickness for different incident energy intensities.

scholarly journals The Impact of a Paraelectric layer in the FE/DE Stack on Performance of NCFET

2022 ◽  
Author(s):  
Harshit Kansal ◽  
Aditya S Medury
Keyword(s):  
Low Power ◽  
Layer Thickness ◽  
Remnant Polarization ◽  
Design Space ◽  
Performance Parameters ◽  
Analog Performance ◽  
Wide Range ◽  
The Impact ◽  
Tcad Simulations ◽  
Mfis Structure

<div>In this letter, through TCAD simulations, we show that the introduction of a thin paraelectric (PE) layer between the ferroelectric (FE) and dielectric (DE) layers in an MFIS structure, expands the design space for the FE layer enabling hysteresis-free and steep subthreshold behavior, even with a thicker FE layer. This can be explained by analyzing the FE-PE stack from a capacitance perspective where the thickness of the PE layer in the FE-PE stack has the effect of reducing the FE layer thickness, while also reducing the remnant polarization. Finally, for the same FE-PE-DE stack, analog performance parameters such as $\frac{g_{m}} g_{ds}}$ and $\frac{g_{m}}{I_{d}}$ are analyzed, showing good characteristics over a wide range of gate lengths, at low drain voltages, thus demonstrating applicability for low power applications.</div>

scholarly journals The Impact of a Paraelectric layer in the FE/DE Stack on Performance of NCFET

2022 ◽  
Author(s):  
Harshit Kansal ◽  
Aditya S Medury
Keyword(s):  
Low Power ◽  
Layer Thickness ◽  
Remnant Polarization ◽  
Design Space ◽  
Performance Parameters ◽  
Analog Performance ◽  
Wide Range ◽  
The Impact ◽  
Tcad Simulations ◽  
Mfis Structure

<div>In this letter, through TCAD simulations, we show that the introduction of a thin paraelectric (PE) layer between the ferroelectric (FE) and dielectric (DE) layers in an MFIS structure, expands the design space for the FE layer enabling hysteresis-free and steep subthreshold behavior, even with a thicker FE layer. This can be explained by analyzing the FE-PE stack from a capacitance perspective where the thickness of the PE layer in the FE-PE stack has the effect of reducing the FE layer thickness, while also reducing the remnant polarization. Finally, for the same FE-PE-DE stack, analog performance parameters such as $\frac{g_{m}} g_{ds}}$ and $\frac{g_{m}}{I_{d}}$ are analyzed, showing good characteristics over a wide range of gate lengths, at low drain voltages, thus demonstrating applicability for low power applications.</div>

Thermal Stability of Strained Si on Relaxed Si1−xGex Buffer Layers

2001 ◽  
Vol 686 ◽  
Author(s):  
P.M. Mooney ◽  
S.J. Koester ◽  
J.A. Ott ◽  
J.L. Jordan-Sweet ◽  
J.O. Chu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Layer Thickness ◽  
Buffer Layers ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Strained Si ◽  
X Ray ◽  
Dislocation Glide ◽  
Transmission Electron ◽  
Thermal Stability Of

AbstractThe thermal stability of strained Si on relaxed Si1−xGex structures annealed at 1000 °C was investigated using high-resolution x-ray diffraction, Raman spectroscopy and transmission electron microscopy. Interdiffusion at the Si/Si1−xGex interface is negligible for annealing times <30 sec and is independent of the initial Si layer thickness and the composition of the Si1−xGex layer. In all cases the Si layers remained nearly fully strained, but a significant density of misfit dislocations was seen in layers that exceeded the critical thickness for dislocation glide. The Si layer thickness could be measured for layers as thin as 7 nm.

Structural Analysis of Sputtered Sc(x)Al(1-x)N Layers for Sensor Applications

2020 ◽  
Vol 865 ◽  
pp. 13-18
Author(s):  
Bernd Hähnlein ◽  
Tim Hofmann ◽  
Katja Tonisch ◽  
Jörg Pezoldt ◽  
Jaroslav Kovac ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Raman Spectroscopy ◽  
Piezoelectric Properties ◽  
High Thermal Stability ◽  
Biaxial Strain ◽  
Sensor Applications ◽  
Magnetoelectric Sensors ◽  
Bond Softening ◽  
The Impact ◽  
Ftir And Raman Spectroscopy

Scandium aluminum nitride (ScxAl1-xN) is a promising material for sensor applications as it exhibits enhanced piezoelectric properties compared to pristine AlN while maintaining other advantageous properties like high thermal stability. Magnetoelectric sensors in particular are used to detect magnetic fields which leads to special requirements regarding the investigated ScAlN in order to achieve high sensor sensitivities. Co-sputtered ScAlN layers are investigated in this work using XRD, XPS, FTIR and Raman spectroscopy for scandium concentrations from 0 to 34 %. The impact of Sc incorporation regarding residual biaxial strain and bond softening is discussed on basis of the experimental results. The activity of the B1 and E2 modes found in the FTIR measurements is of special interest as the presumably oxygen related excitation is expected to influence the piezoelectric properties.

Hrxrd Study of the Strain Properties of MBE-Grown ZnSe and ZnSTe on GaAs

1994 ◽  
Vol 340 ◽  
Author(s):  
I.K. Sou ◽  
S.M. Mou ◽  
Y.W. Chan ◽  
G.C. Xu ◽  
G.K.L. Wong
Keyword(s):  
Layer Thickness ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Dynamical Theory ◽  
X Ray Diffraction ◽  
Strained Layers ◽  
X Ray ◽  
Znse Layer ◽  
Vegard’S Law ◽  
First Time

ABSTRACTWe have studied the structural properties of MBE-grown ZnSe/GaAs and ZnSTe/GaAs heterostructures using high resolution X-ray diffraction (HRXRD). The transition from pseudomorphic to partially and then fully relaxed strained layers is observed as a function of ZnSe layer thickness. The critical thickness for the on-set of strained relaxation for ZnSe on GaAs(001) is determined to be between 1600 and 1850 Å. Using a simulation program based on the dynamical theory, the poisson's ratio of ZnSe is accurately determined to be v=0.380±0.002. A set of ZnSl-xTex epilayers with 0 ≤ × ≤ 1 was grown on GaAs by MBE for the first time. A linear dependence of the lattice constant upon Te composition is found, which agrees well with the Vegard's Law. The characteristic behaviors of inclination between the layer and substrate planes as a function of layer thickness has been studied on both ZnSe/GaAs and ZnSTe/GaAs systems. The atomic planes of both ZnSe and ZnSTe layers are observed to tilt from those of the GaAs substrate.

scholarly journals Novel Micro- and Nanocellulose-Based Delivery Systems for Liposoluble Compounds

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2593
Author(s):  
Francisca Casanova ◽  
Carla F. Pereira ◽  
Alessandra B. Ribeiro ◽  
Ricardo Freixo ◽  
Eduardo Costa ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Water Solubility ◽  
Biological Activities ◽  
Aqueous Solubility ◽  
Delivery Systems ◽  
Great Promise ◽  
Gastrointestinal Conditions ◽  
Wide Range ◽  
State Of Research ◽  
The Impact

Poor aqueous solubility of bioactive compounds is becoming a pronounced challenge in the development of bioactive formulations. Numerous liposoluble compounds have very interesting biological activities, but their low water solubility, stability, and bioavailability restrict their applications. To overcome these limitations there is a need to use enabling delivering strategies, which often demand new carrier materials. Cellulose and its micro- and nanostructures are promising carriers with unique features. In this context, this review describes the fast-growing field of micro- and nanocellulose based delivery systems with a focus on the release of liposoluble bioactive compounds. The state of research on this field is reviewed in this article, which also covers the chemistry, preparation, properties, and applications of micro- and nanocellulose based delivery systems. Although there are promising perspectives for introducing these materials into various fields, aspects of safety and toxicity must be revealed and are discussed in this review. The impact of gastrointestinal conditions on the systems and on the bioavailability of the bioactive compounds are also addressed in this review. This article helps to unveil the whole panorama of micro- and nanocellulose as delivery systems for liposoluble compounds, showing that these represent a great promise in a wide range of applications.

THE IMPACT OF LEADERSHIP PRACTICES TO TEAM MEMBERS’ SATISFACTION

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Chalimah .
Keyword(s):  
Conflict Resolution ◽  
Leadership Practices ◽  
Hotel Industry ◽  
Leader Behavior ◽  
Team Leader ◽  
Shop Floor ◽  
Team Members ◽  
Top Executives ◽  
Wide Range ◽  
The Impact

eamwork is becoming increasingly important to wide range of operations. It applies to all levels of the company. It is just as important for top executives as it is to middle management, supervisors and shop floor workers. Poor teamwork at any level or between levels can seriously damage organizational effectiveness. The focus of this paper was therefore to examine whether leadership practices consist of team leader behavior, conflict resolution style and openness in communication significantly influenced the team member’s satisfaction in hotel industry. Result indicates that team leader behavior and the conflict resolution style significantly influenced team member satisfaction. It was surprising that openness in communication did not affect significantly to the team members’ satisfaction.

Stress, anxiety, depression and burnout in frontline health care workers during COVID-19 pandemic: a brief systematic review and new data from Russia

2021 ◽  
Author(s):  
Ekaterina Mosolova ◽  
Dmitry Sosin ◽  
Sergey Mosolov
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Female Gender ◽  
Assessment Tools ◽  
Care Workers ◽  
Younger Age ◽  
Wide Range ◽  
Associated Risk Factors ◽  
Anxiety Depression ◽  
The Impact

During the COVID-19 pandemic, healthcare workers (HCWs) have been subject to increased workload while also exposed to many psychosocial stressors. In a systematic review we analyze the impact that the pandemic has had on HCWs mental state and associated risk factors. Most studies reported high levels of depression and anxiety among HCWs worldwide, however, due to a wide range of assessment tools, cut-off scores, and number of frontline participants in the studies, results were difficult to compare. Our study is based on two online surveys of 2195 HCWs from different regions of Russia during spring and autumn epidemic outbreaks revealed the rates of anxiety, stress, depression, emotional exhaustion and depersonalization and perceived stress as 32.3%, 31.1%, 45.5%, 74.2%, 37.7% ,67.8%, respectively. Moreover, 2.4% of HCWs reported suicidal thoughts. The most common risk factors include: female gender, nurse as an occupation, younger age, working for over 6 months, chronic diseases, smoking, high working demands, lack of personal protective equipment, low salary, lack of social support, isolation from families, the fear of relatives getting infected. These results demonstrate the need for urgent supportive programs for HCWs fighting COVID-19 that fall into higher risk factors groups.

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