A Study on the Optimization of the Recessed Silicon Germanium Junction Parameters of P-channel MOSFETs with Channels Under Uniaxial Compressive Strain PDF Download
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Author: Saurabh Chopra
Publisher:
ISBN:
Category :
Languages : en
Pages : 201
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Book Description
Recessed Si1-xGe x source/drain technology enhances the performance of state of the art metal oxide semiconductor field effect transistors (MOSFETs), by providing enhanced channel mobility and reduced source/drain contact resistivity. This dissertation focuses on the effects of recessed Si1- xGex junction parameters on the biaxial compressive strain in Si1-xGe x and their impact on the bandgap and contact resistivity. Due to its smaller size, boron can partially compensate the compressive strain in Si1-xGex. This behavior was modeled using the covalent radii of Si, Ge and B, to calculate the lattice parameter of the ternary Si1-x-y GexBy alloy. It was also shown using micro-Raman spectroscopy that Houghton's kinetic model accurately predicted the Si1-x-y GexBy critical thickness. Formation of NiSi1-xGe x on Si1-xGe x was also studied, and it was found that NiSi1- xGex induced tensile strain in Si1-xGe x, thereby reducing the compressive strain in the junctions. The impact of the NiSi1-xGe x thickness on Si1-xGe x bandgap was investigated using p+(Si 1-xGex)-n(Si) diodes, and it was demonstrated that increasing the NiSi1- xGex thickness led to an increase in the bandgap, due to loss in compressive strain. It was also shown that the barrier height followed the Si1-xGe x bandgap and increased with NiSi1- xGex thickness. The impact of the Si1-xGex bandgap and the barrier height on contact resistivity was studied using four-terminal Kelvin structures. It was shown that contact resistivity increased with Si 1-xGex thickness and NiSi1-xGe x thickness, due to reduced biaxial compressive strain. It was shown that with fully strained Si1-xGe x junctions, and a germanium concentration of x=0.28, a minimum contact resistivity of 2.5x10-8 Ocm 2 could be obtained. While the experiments in this dissertation are limited to Si1-xGe x and NiSi1-xGe x contacts, the fundamental knowledge gained from this work is expected to have a much wider impact. Specifically, this thesis introduces strain as a new parameter in contact engineering because of its impact on the semiconductor band structure and the metal-semiconductor barrier height, regardless of the metal and semiconductor choices.
Author: Saurabh Chopra
Publisher:
ISBN:
Category :
Languages : en
Pages : 201
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Book Description
Recessed Si1-xGe x source/drain technology enhances the performance of state of the art metal oxide semiconductor field effect transistors (MOSFETs), by providing enhanced channel mobility and reduced source/drain contact resistivity. This dissertation focuses on the effects of recessed Si1- xGex junction parameters on the biaxial compressive strain in Si1-xGe x and their impact on the bandgap and contact resistivity. Due to its smaller size, boron can partially compensate the compressive strain in Si1-xGex. This behavior was modeled using the covalent radii of Si, Ge and B, to calculate the lattice parameter of the ternary Si1-x-y GexBy alloy. It was also shown using micro-Raman spectroscopy that Houghton's kinetic model accurately predicted the Si1-x-y GexBy critical thickness. Formation of NiSi1-xGe x on Si1-xGe x was also studied, and it was found that NiSi1- xGex induced tensile strain in Si1-xGe x, thereby reducing the compressive strain in the junctions. The impact of the NiSi1-xGe x thickness on Si1-xGe x bandgap was investigated using p+(Si 1-xGex)-n(Si) diodes, and it was demonstrated that increasing the NiSi1- xGex thickness led to an increase in the bandgap, due to loss in compressive strain. It was also shown that the barrier height followed the Si1-xGe x bandgap and increased with NiSi1- xGex thickness. The impact of the Si1-xGex bandgap and the barrier height on contact resistivity was studied using four-terminal Kelvin structures. It was shown that contact resistivity increased with Si 1-xGex thickness and NiSi1-xGe x thickness, due to reduced biaxial compressive strain. It was shown that with fully strained Si1-xGe x junctions, and a germanium concentration of x=0.28, a minimum contact resistivity of 2.5x10-8 Ocm 2 could be obtained. While the experiments in this dissertation are limited to Si1-xGe x and NiSi1-xGe x contacts, the fundamental knowledge gained from this work is expected to have a much wider impact. Specifically, this thesis introduces strain as a new parameter in contact engineering because of its impact on the semiconductor band structure and the metal-semiconductor barrier height, regardless of the metal and semiconductor choices.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
It has been shown that recessed SiGe source/drain technology enhances the performance of metal oxide semiconductor field effect transistors (MOSFETs), by providing enhanced channel mobility and reduced source/drain contact resistivity. The focus of this dissertation is to study the effect of the recessed SiGe junction parameters on the biaxial compressive strain in SiGe, and its impact on the bandgap and contact resistivity. Due to its smaller size, boron can partially compensate the compressive strain in SiGe. This behavior was modeled using the covalent radii of Si, Ge and B, to calculate the lattice parameter of the ternary SiGeB alloy. It was also shown using micro-Raman spectroscopy that Houghton's kinetic model accurately predicted the SiGeB critical thickness. Formation of NiSiGe on SiGe was also studied, and it was found that NiSiGe induced tensile strain in SiGe, thereby reducing the compressive strain in the junctions. The impact of the NiSiGe thickness on SiGe bandgap was also studied using p(SiGe)-n(Si) diodes, and it was shown that increasing the NiSiGe thickness led to an increase in the bandgap, due to loss in compressive strain. It was also shown that the barrier height followed the SiGe bandgap, and hence increased with NiSiGe thickness. The impact of the SiGe bandgap and the barrier height on contact resistivity was studied using four-terminal Kelvin structures. It was shown that contact resistivity increased with SiGe thickness and NiSiGe thickness, due to reduced biaxial compressive strain. It was shown that with fully strained SiGe junctions, and a germanium concentration of x=0.28, a minimum contact resistivity of 2.5 X 10−8 Ohm-cm2 could be obtained. While the experiments in this dissertation are limited to SiGe and NiSiGe contacts, the fundamental knowledge gained from this work is expected to have a much wider impact. Specifically, this thesis introduces strain as a new parameter in contact engineering because of its.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 752
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Book Description
ABSTRACTSilicon Germanium (Si1-xGex) is an alloy semiconductor that has caught considerable attention of the semiconductor industry in the past decade. Effects of strain in thin films are the reason for this. Strain leads to considerable deformation of bands providing enhanced mobility for both electrons and holes. Another important aspect of SiGe is the reduction of band gap. This makes band gap engineering feasible in all silicon technology. Yet another attractive point is the adaptability and compatibility of SiGe to silicon process technology. In CMOS circuits the p-channel MOSFET needs more than double the area of the n-channel MOSFET due to the lower mobility of holes in silicon. Hence a p-channel hetero MOSFET (HMOSFET) is chosen as the object of this dissertation. A simple general device structure that can provide considerable enhancement in performance, compared to a conventional MOSFET, is selected. A one dimensional Poisson equation is solved for this hetero junction device. Using these results an Excel spreadsheet is used as a tool to design a complete analytical program that can provide internal as well as terminal parameters of this device. The analytical program is tested by comparing the results with ISE-TCAD numerical device simulator results. The results were found to match very well. This analytical program yields results in a fraction of the time compared to numerical programs. For the device of choice variable parameters are identified. It is found that these parameters are interconnected in many ways and trade offs between them need to be applied. From the front end of the spreadsheet input parameters can be varied and parameters like potentials, hole density and terminal characteristics can be plotted very easily while simultaneously computing other parameters like threshold voltage and saturation current. The main contribution of this dissertation research is(1) Development of a very efficient and accurate analytical program to interactively design and optimize a p-channel HMOSFET(2) A detailed understanding and explanation of various design parameters, their implications, interdependency and trade offs(3) Study and explanation of certain special characteristics ofp-HMOSFET like dual threshold voltage, low off-currents, structural limitations etc.
Author: Leonardo Gomez (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 167
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Book Description
Since the 90 nm CMOS technology node, geometric scaling of CMOS has been supplemented with strain to boost transistor drive current. Future CMOS technology nodes (i.e. beyond the 32 nm node) will require more significant changes to continue improvements in transistor performance. Novel CMOS channel materials and device architectures are one option for enhancing carrier transport and increasing device performance. In this work strained SiGe and Ge are examined as a means of increasing the drive current in deeply scaled CMOS. As part of this work a novel high mobility strained-Ge on-insulator substrate has been developed, and the hole transport characteristics of short channel and asymmetrically strained-SiGe channel p-MOSFETs have been explored. A thin-body biaxial compressive strained-Si/strained-Ge heterostructure on-insulator (HOI) substrate has been developed, which combines the electrostatic benefits of the thin-body architecture with the transport benefits of biaxial compressive strain. A novel Germanium on Silicon growth method and a low temperature bond and etch-back process have been developed to enable Ge HOI fabrication. P-MOSFETs were also fabricated using these substrates and the hole mobility characteristics were studied. The hole mobility and velocity characteristics of short channel biaxial compressive strained-Si 45 Geo. 55 p-MOSFETs on-insulator have also been examined. Devices with gate lengths down to 65 nm were fabricated. The short channel mobility characteristics were extracted and a 2.4x hole mobility enhancement relative to relaxed-Si was observed. The measured hole velocity enhancement is more modest at about 1.2x. Band structure and ballistic velocity simulations suggest that a more substantial velocity improvement can be expected with the incorporation of added longitudinal uniaxial compressive strain in the SiGe channel. The hole mobility characteristics of biaxial strained SiGe and Ge p-MOSFETs with applied uniaxial strain are also studied. The hole mobility in biaxial compressive strained SiGe is already enhanced relative to relaxed Si. It is observed that this mobility enhancement increases further with the application of 110 longitudinal uniaxial compressive strain. Since hole mobility and velocity are correlated through their dependence on the hole effective mass, a mass driven increase in mobility with applied uniaxial strain should result in an increase in velocity. Simulations have also been performed to estimate the hole effective mass change in asymmetric strained SiGe. Finally the piezo resistance coefficients of strained SiGe are extracted and found to be larger than in Si.
Author: Yongke Sun
Publisher: Springer Science & Business Media
ISBN: 1441905529
Category : Technology & Engineering
Languages : en
Pages : 353
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Book Description
Strain Effect in Semiconductors: Theory and Device Applications presents the fundamentals and applications of strain in semiconductors and semiconductor devices that is relevant for strain-enhanced advanced CMOS technology and strain-based piezoresistive MEMS transducers. Discusses relevant applications of strain while also focusing on the fundamental physics pertaining to bulk, planar, and scaled nano-devices. Hence, this book is relevant for current strained Si logic technology as well as for understanding the physics and scaling for future strained nano-scale devices.
Author: Guilei Wang
Publisher: Springer Nature
ISBN: 9811500460
Category : Technology & Engineering
Languages : en
Pages : 115
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Book Description
This thesis presents the SiGe source and drain (S/D) technology in the context of advanced CMOS, and addresses both device processing and epitaxy modelling. As the CMOS technology roadmap calls for continuously downscaling traditional transistor structures, controlling the parasitic effects of transistors, e.g. short channel effect, parasitic resistances and capacitances is becoming increasingly difficult. The emergence of these problems sparked a technological revolution, where a transition from planar to three-dimensional (3D) transistor design occurred in the 22nm technology node. The selective epitaxial growth (SEG) method has been used to deposit SiGe as stressor material in S/D regions to induce uniaxial strain in the channel region. The thesis investigates issues of process integration in IC production and concentrates on the key parameters of high-quality SiGe selective epitaxial growth, with a special focus on its pattern dependency behavior and on key integration issues in both 2D and 3D transistor structures, the goal being to improve future applications of SiGe SEG in advanced CMOS.
Author: Cor Claeys
Publisher: Elsevier
ISBN: 008047490X
Category : Science
Languages : en
Pages : 476
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Book Description
Germanium is a semiconductor material that formed the basis for the development of transistor technology. Although the breakthrough of planar technology and integrated circuits put silicon in the foreground, in recent years there has been a renewed interest in germanium, which has been triggered by its strong potential for deep submicron (sub 45 nm) technologies. Germanium-Based technologies: From Materials to Devices is the first book to provide a broad, in-depth coverage of the field, including recent advances in Ge-technology and the fundamentals in material science, device physics and semiconductor processing. The contributing authors are international experts with a world-wide recognition and involved in the leading research in the field. The book also covers applications and the use of Ge for optoelectronics, detectors and solar cells. An ideal reference work for students and scientists working in the field of physics of semiconductor devices and materials, as well as for engineers in research centres and industry. Both the newcomer and the expert should benefit from this unique book. - State-of-the-art information available for the first time as an all-in-source - Extensive reference list making it an indispensable reference book - Broad coverage from fundamental aspects up to industrial applications
Author: Serge Oktyabrsky
Publisher: Springer Science & Business Media
ISBN: 1441915478
Category : Technology & Engineering
Languages : en
Pages : 451
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Book Description
Fundamentals of III-V Semiconductor MOSFETs presents the fundamentals and current status of research of compound semiconductor metal-oxide-semiconductor field-effect transistors (MOSFETs) that are envisioned as a future replacement of silicon in digital circuits. The material covered begins with a review of specific properties of III-V semiconductors and available technologies making them attractive to MOSFET technology, such as band-engineered heterostructures, effect of strain, nanoscale control during epitaxial growth. Due to the lack of thermodynamically stable native oxides on III-V's (such as SiO2 on Si), high-k oxides are the natural choice of dielectrics for III-V MOSFETs. The key challenge of the III-V MOSFET technology is a high-quality, thermodynamically stable gate dielectric that passivates the interface states, similar to SiO2 on Si. Several chapters give a detailed description of materials science and electronic behavior of various dielectrics and related interfaces, as well as physics of fabricated devices and MOSFET fabrication technologies. Topics also include recent progress and understanding of various materials systems; specific issues for electrical measurement of gate stacks and FETs with low and wide bandgap channels and high interface trap density; possible paths of integration of different semiconductor materials on Si platform.
Author: Lining Zhang
Publisher: Springer
ISBN: 3319316532
Category : Technology & Engineering
Languages : en
Pages : 217
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Book Description
This book provides a single-source reference to the state-of-the art in tunneling field effect transistors (TFETs). Readers will learn the TFETs physics from advanced atomistic simulations, the TFETs fabrication process and the important roles that TFETs will play in enabling integrated circuit designs for power efficiency.
Author: Mark Lundstrom
Publisher: Springer Science & Business Media
ISBN: 0387280030
Category : Technology & Engineering
Languages : en
Pages : 223
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Book Description
To push MOSFETs to their scaling limits and to explore devices that may complement or even replace them at molecular scale, a clear understanding of device physics at nanometer scale is necessary. Nanoscale Transistors provides a description on the recent development of theory, modeling, and simulation of nanotransistors for electrical engineers, physicists, and chemists working on nanoscale devices. Simple physical pictures and semi-analytical models, which were validated by detailed numerical simulations, are provided for both evolutionary and revolutionary nanotransistors. After basic concepts are reviewed, the text summarizes the essentials of traditional semiconductor devices, digital circuits, and systems to supply a baseline against which new devices can be assessed. A nontraditional view of the MOSFET using concepts that are valid at nanoscale is developed and then applied to nanotube FET as an example of how to extend the concepts to revolutionary nanotransistors. This practical guide then explore the limits of devices by discussing conduction in single molecules
