High-k Gate Dielectrics for CMOS Technology

PREFACE

PART ONE: Scaling and Challenge of Si-based CMOS

SCALING AND LIMITATION OF SI-BASED CMOS
Introduction
Scaling and Limitation of CMOS
Toward Alternative Gate Stacks Technology
Improvements 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
Introduction
High-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 Films
Photoinduced 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 APPLICATIONS
Introduction
Requirement of High-k Oxide Materials
Rare-Earth Oxide as Alternative Gate Dielectrics
Structural Characteristics of High-k RE Oxide Films
Electrical Characteristics of High-k RE Oxide Films
Conclusions 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 Films
Hygroscopic 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 ALIGNMENT
Introduction
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 Interfaces
Metal 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 PLATFORM
Introduction
High-k/Si CMOSFETs
High-k/Ge CMOSFETs
Ge Platform
Conclusions

THEORETICAL PROGRESS ONGAAS (001)SURFACE ANDGAAS/HIGH-K INTERFACE
Introduction
Computational Method
GaAs 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 DIELECTRICS
Introduction
Buried 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 Processes
Mobility
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
Reliability
Conclusions

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 in novel devices. Due to his outstanding performance in research work, Professor Gang 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 and solar cells. Professor Zhaoqi Sun has authored more than 140 scientific publications
and has received numerous scientific awards, including the Science and Technology Award of the AnhuiProvince and an Outstanding Teacher Award.

G. He, Anhui University, Hefei, P.R. China; Z. Sun, Anhui University, Hefei, P.R. China