Introduction of FINFET and CMOSSeries on Integrated Circuits and systemsSeries editorAnantha ChandrakasanMassachusetts Institute of TechnologyCambridge, MassachusettsFinFets and other multi-Gate transistorsJean-Pierre Colinge(Ed)ISBN978-0-387-71751-7Design for Manufacturability and Statistical Design: A Constructive ApproachMichael Orshansky, Sani r Nassif, and Duane BoningISBN978-0-387-30928-6Low Power Methodology manual: For System-on-Chip designMichael Keating, David Flynn, Rob Aitken, Alan Gibbons, and Kaijian ShiISBN9780-387-71818-7Modern circuit placement: best practices and resultsGi-Joon Nam and Jason CongISBN978-0-387-36837-5CMOS BiotechnologyHakho Lee. Donhee ham and robert m. westerveltISBN9780-387-36836-8SAT-Based Scalable formal verification solutionsMalay ganai and Aarti GuptaISBN978-0-387-69166-4,2007Ultra-Low Voltage Nano-Scale MemoriesKiyoo Itoh. Masashi horiguchi and Hitoshi TanakaISBN978-0-387-33398-4,2007Routing Congestion in VLSI Circuits: Estimation and OptimizationPrashant Saxena, Rupesh S. Shelar, Sachin SapatnekarISBN978-0-387-30037-5,2007Ultra-Low Power Wireless Technologies for Sensor NetworksBrian Otis and Jan rabaeyISBN978-0-387-30930-9,2007Sub-Threshold Design for Ultra Low-Power SystemsAlice Wang, Benton H. Calhoun and Anantha ChandrakasanISBN978-0-387-33515-5,2006High Performance Energy Efficient Microprocessor DesignVojin Oklibdzija and ram Krishnamurthy(EdsISBN978-0-387-28594-8,2006Abstraction Refinement for Large Scale Model CheckingChao Wang, Gary D Hachtel, and Fabio SomenziISBN978-0-387-28594-2,2006a Practical Introduction to pslCindy eisner and dana fismanISBN978-0-387-35313-5,2006Thermal and Power Management of Integrated SystemsArman Vassighi and Manoj sachdevISBN978-0-387-25762-4,2006Continued after indexJean-Pierre ColingeEditorFinFets and otherMulti-Gate TransistorsringerJean-Pierre ColingeTyndall national InstituteCork. relandseries editorAnantha ChandrakasanDepartment of Electrical Engineering and Computer ScienceMassachusetts institute of technologyCambridge, MA 02139USALibrary of Congress Control Number: 2007935904ISBN9780-38771751-7e-ISBN978-0-387-717524Printed on acid-free paperc 2008 Springer Science+ Business Media, LLCAll rights reserved. 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Theuse in this publication of trade names, trademarks, service marks and similar terms, even if they are notdentified as such, is not to be taken as an expression of opinion as to whether or not they are subject toproprietary rights987654321springer. comPrefacee adoption of Silicon-on-Insulator (SOi) substrates for themanufacturing of mainstream semiconductor products such asmicroprocessors has given SOI research an unprecedented impetus In thepast, novel transistor structures proposed by SoI scientists were oftenconsidered exotic and impractical, but the recent success of soi in thefield of microprocessor manufacturing has finally given this technologythe credibility and acceptance it deservesThe classical CMOS Structure is reaching its scaling limits andend-of-roadmap 'alternative devices are being investigated. Amongst the differenttypes of soi devices proposed one clearly stands out: the multigate fieldeffect transistor (multigate FET). This device has a general"wire-likeshape with a gate electrode that controls the flow of current betweensource and drain. Multigate FETs are commonly referred to as"multi(ple)-gate transistors”,“ wrapped- gate transistors”,“ double- gate transistors”,FinFets”,"“tri(ple)- gate transistors”,“ Gate-ll- Around transistors”,etcThe International Technology Roadmap for Semiconductors (ITRSrecognizes the importance of these devices and calls them"Advanced nonclassical cmos devices”’There exists a number of textbooks on soi technology. Some of thesebooks tackle the subject of multigate Fets but there is no book thatcontains a comprehensive description of the physics, technology andcircuit applications of this new class of devices. This is why we decided tocompile chapters dedicated to the different facets of multigate Fettechnology, written by world-leading experts in the field. This bookcontains seven chaptersⅤ i PrefaceChapter 1: The soI MOSFET: from Single Gate to Multigate, byJean-Pierre Colinge, is a general introduction that shows theevolution of the soi mos transistor and retraces the history of themultigate concept. The advantages of multigate FETs in terms ofelectrostatic integrity and short-channel control are described, andthe challenges posed by the appearance of novel effects some ofquantum-mechanical origin, are outlinedChapter 2: Multigate MOSFET Technology, by Weize (Wade)Xiong, outlines the issues associated with multigate FETmanufacturing. This chapter describes thin-fin formationtechniques, advanced gate stack deposition and source/drainresistance reduction techniques. Issues related to fin crystalorientation and mobility enhancement via strain engineering aretackled as wellChapter 3: BSIM CMG: A Compact Model for Multi-GateTransistors, by Mohan Vamsi Dunga, Chung-Hsun Lin, Ali MNiknejad and Chenming Hu, describes the physics behind theBSIM-CMG Berkeley Short-channel IGFET Model- CommonMulti-Gate) compact models for multigate MOSFETs. A compactmodel serves as a link between process technology and circuitdesign. It is a concise mathematical description of the devicephysics in the transistor. Some simplifications in the physicshowever, can be made to enable fast computer analysis ofdevice/circuit behaviorChapter 4: Physics of the Multigate MOS System, by BogdanMajkusiak analyzes the electrostatics of the multigate mossystem. Using quantum-mechanical concepts it describes electronenergy quantization and the properties of a one-dimensional andtwo-dimensional electron gas. The effects of tunneling through thingate dielectrics on the electron population of a device are studied aswellPreface viChapter 5: Mobility in Multigate MOSFETS, by Francisco Gamizd andres godethe behavior of electron mobility idifferent multigate structures comprising double-gate transistors,FinFETs, and silicon nanowires Mobility in multiple gate devicesis compared to that in single-gate devices and different approachesfor improving the mobility in these devices, such as differentcrystallographic orientations and strained Si channels, are studiedChapter 6: Radiation Effects in Advanced Single- and Multi-GateSOI MOSFETS, by Veronique Ferlet-Cavrois, Philippe Paillet andOlivier faynot, describes the effects of ionizing radiations such asgamma rays and cosmic rays on SOI MOSFETs. These effects areextremely important in military, space and avionics applicationsMulti-gate FETs show exceptional resistance to total-dose andsingle-event effects and could become the new standard inradiation-hardened electronicsChapter 7: Multigate MOsFEt Circuit Design, by GerhardKnoblinger, Michael Fulde and Christian Pacha, describes theinterrelationship between the multi-gate Fet device properties andelementary digital and analog circuits, such as CMOs logic gatesSRAM cells, reference circuits, operational amplifiers, and mixedsignal building blocks. This approach is motivated by theobservation that a cost-efficient, heterogeneous Soc integration is akey factor in modern IC designJean-Pierre Colinge, August 2007Table of contentPrefaceTable of contentContributors .mmmmmmmmmmmmmmmmmommxvI The SoI MOsFET: from Single Gate to multigateMOSFET Scaling and moores law1. 2 Short-Channel Effects3 Gate Geometry and Electrostatic Integrity112481. 4 a Brief History of Multiple- Gate MOSFEts............81.4.1 Single- gate SOI MOSFETS….…91.4.2 Double-gate SOI MOSFETs1.4.3 Triple-gate SOI MOSFets121.4.4 Surrounding-gate(quadruple-gate)SOI MOSFETS....134. 5 Other multigate MOSFet structures141.4.6 Multigate MOSFET memory devices……65 Multigate mosFet physics1.5. 1 Classical physics171.5.1.1 Natural length and short-channel effects1.5.1.2 Current drive. ...............................................................231.5.1 3 Corner effect5.2 Quantum effects281.5.2.1 Volume inversion281.5.2.2 Mobility effects1. 5.2. 3 Threshold voltage1.5.2. 4 Inter-subband scattering35References ......................................................................................37x Table of content2 Multigate Mosfet Technology2.1 Introduction2.2 Active area: fins∴522.2.1 Fin width522.2.2 Fin Height and fin pitch…572.2.3 Fin Surface Crystal Orientation612.2.4 Fin Surface Preparation642.2.5 Fins on Bulk silicon652.2.6 Nano-wires and self-AsSembled Wires ..........................662. 3 Gate Stack702.3.1 Gate Patterning……702.3.2 Threshold Voltage and gate Workfunction requirements. ....712. 3.2. 1 Polysilicon Gate742.3.2.2 Metal Gate…752.3.2. 3 Tunable Workfunction Metal Gate∴752.3.3 Gate EWF and Gate Induced Drain Leakage(GIDL2.3. 4 Independently controlled gates..................822.4 Source/Drain Resistance and Capacitance.2.4. 1 Doping the Thin fins..............................852.4.2 Junction Depth872.4.3 Parasitic Resistance/Capacitance and raised Sourceand drain structure,·872.5 Mobility and Strain Engineering912.5.1 Introduction2.5.2 Wafer Bending experiment..…..…...….....922.5.3 Nitride Stress liners932.5.4 Embedded SiGe and SiC Source and drain..........942.5.5 Local Strain from Gate Electrode952.5.6 Substrate Strain: Strained Silicon on Insulator.........972. 6 Contacts to the fins982.6. 1 Dumbbell source and drain contact2.6.2 Saddle contact992.6. 3 Contact to merged fins100Acknowledgments100References101