High-k Gate Dielectrics for CMOS Technology

Gang He is Professor at the School of Physics and Materials Science of the Anhui University, China. He obtained his academic degrees from the Institute of Solid State Physics of the Chinese Academy of Sciences. His research interests and efforts cover the areas of the preparation, characterization, fundamental understanding and associated applications of high-k gate dielectric thin films. Due to his outstanding performance in research work, he won a scholarship award from the Chinese Academy of Sciences in 2005 and a grant of the Japanese Society for the Promotion of Science in 2006. Zhaoqi Sun is the President of the School of Physics and Materials Science at the Anhui University. He graduated from Sichuan University and obtained his academic degrees from the University of Science and Technology of China. His research is focused on functional thin film materials for applications in microelectronics. Zhaoqi Sun has authored more than 140 scientific publications and has received numerous scientific awards, including the Science and Technology Award of the Anhui Province and an Outstanding Teacher Award.

• PREFACE PART ONE: Scaling and Challenge of Si-based CMOS SCALING AND LIMITATION OF SI-BASED CMOS Introduction Scaling and Limitation of CMOSToward Alternative Gate Stacks TechnologyImprovements and Alternative to CMOS Technologies Potential Technologies Beyond CMOS Conclusions PART TWO: High-k Deposition and Materials Characterization ISSUES IN HIGH-K GATE DIELECTRICS AND ITS STACK INTERFACES IntroductionHigh-k Dielectrics Metal Gates Integration of High-k Gate Dielectrics with Alternative Channel Materials Summary UV ENGINEERING OF HIGH-K THIN FILMS Introduction Gas Discharge Generation of UV (Excimer) Radiation Excimer Lamp Sources Based on Silent Discharges Predeposition Surface Cleaning for High-k Layers UV Photon Deposition of Ta2O5 FilmsPhotoinduced Deposition of Hf1_xSixOy Layers Summary ATOMIC LAYER DEPOSITION PROCESS OF HF-BASED HIGH-K GATE DIELECTRIC FILM ON SI SUBSTRATE Introduction Precursor Effect on the HfO2 Characteristics Doped and Mixed High-k Summary STRUCTURAL AND ELECTRICAL CHARACTERISTICS OF ALTERNATIVE HIGH-K DIELECTRICS FOR CMOS APPLICATIONSIntroduction Requirement of High-k Oxide MaterialsRare-Earth Oxide as Alternative Gate Dielectrics Structural Characteristics of High-k RE Oxide Films Electrical Characteristics of High-k RE Oxide FilmsConclusions and Perspectives HYGROSCOPIC TOLERANCE AND PERMITTIVITY ENHANCEMENT OF LANTHANUM OXIDE (LA2O3) FOR HIGH-K GATE INSULATORS Introduction Hygroscopic Phenomenon of La2O3 Films Low Permittivity Phenomenon of La2O3 Films Hygroscopic Tolerance Enhancement of La2O3 FilmsHygroscopic Tolerance Enhancement of La2O3 Films by Ultraviolet Ozone Treatment Thermodynamic Analysis of Moisture Absorption Phenomenon in High-k Gate Dielectrics Permittivity Enhancement of La2O3 Films by Phase Control Summary CHARACTERIZATION OF HIGH-K DIELECTRIC INTERNAL STRUCTURE BY X-RAY SPECTROSCOPY AND REFLECTOMETRY: NEW APPROACHES TO INTERLAYER IDENTIFICATION AND ANALYSIS Introduction Chemical Bonding and Crystalline Structure of Transition Metal Dielectrics NEXAFS Investigation of Internal Structure Studying the Internal Structure of High-K Dielectric Films by Hard X-Ray Photoelectron Spectroscopy and TEM Studying the Internal Structure of High-K Dielectric Films by X-ray Reflectometry HIGH-K INSULATING FILMS ON SEMICONDUCTORS AND METALS: GENERAL TRENDS IN ELECTRON BAND ALIGNMENTIntroduction Band Offsets and IPE Spectroscopy Silicon/Insulator Band Offsets Band Alignment at Interfaces of High-Mobility Semiconductors Metal/Insulator Barriers Conclusions PART THREE: Challenge in Interface Engineering and Electrode INTERFACE ENGINEERING IN THE HIGH-K DIELECTRIC GATE STACKS Introduction High-k Oxide/Si InterfacesMetal Gate/High-k Dielectric Interfaces Chemical Tuning of Band Alignments for Metal Gate/High-k Oxide Interfaces Summary and Discussion INTERFACIAL DIPOLE EFFECTS ON HIGH-K GATE STACKS Introduction Metal Gate Consideration Interfacial Dipole Effects in High-k Gate Stacks Observation of the Interfacial Dipole in High-k Stacks Summary METAL GATE ELECTRODE FOR ADVANCED CMOS APPLICATION The Scaling and Improved Performance of MOSFET Devices Urgent Issues about MOS Gate Materials for Sub-0.1 mm Device Gate Stack New Requirements of MOS Gate Materials for Sub-0.1 mm Device Gate Stack Summary PART FOUR: Development in non-Si-based CMOS technology METAL GATE/HIGH-K CMOS EVOLUTION FROM SI TO GE PLATFORMIntroductionHigh-k/Si CMOSFETs High-k/Ge CMOSFETs Ge PlatformConclusions THEORETICAL PROGRESS ONGAAS (001)SURFACE ANDGAAS/HIGH-K INTERFACE IntroductionComputational MethodGaAs Surface Oxidation and Passivation Origin of Gap States at the High-k/GaAs Interface and Interface Passivation Conclusions III -V MOSFETS WITH ALD HIGH-K GATE DIELECTRICSIntroductionBuried Channel InGaAs MOSFETs Summary PART FIVE: High-k Application in Novel Devices HIGH-K DIELECTRICS IN FERROELECTRIC GATE FIELD EFFECT TRANSISTORS FOR NONVOLATILE MEMORY APPLICATIONS Introduction Overview of High-k Dielectric Studies for FeFET Applications Developing of HfTaO Buffer Layers for FeFET Applications Summary RARE-EARTH OXIDES AS HIGH-K GATE DIELECTRICS FOR ADVANCED DEVICE ARCHITECTURES Introduction Key Challenges for High-k Dielectrics Rare-Earth Oxides as High-k Dielectrics High-k Dielectrics in Advanced Device Architecture PART SIX: Challenge and Future Directions THE INTERACTION CHALLENGES WITH NOVEL MATERIALS IN DEVELOPING HIGH-PERFORMANCE AND LOW-LEAKAGE HIGH-K/METAL GATE CMOS TRANSISTORS Introduction Traditional CMOS Integration Processes High-k/Metal Gate Integration ProcessesMobility Metal Electrodes and Effective Work Function Tinv Scaling and Impacts on Gate Leakage and Effective Work Function Ambients and Oxygen Vacancy-Induced Modulation of Threshold Voltage ReliabilityConclusions