Using tabulated thermodynamic data, a comprehensive investigation of the thermo-dynamic stability of binary oxides in contact with silicon at 1000 K was conducted. Reactions between silicon and each binary oxide at 1000 K, including those involving ternary phases, were considered. Sufficient data exist to conclude that all binary oxides except the following are thermodynamically unstable in contact with silicon at 1000 K: Li2O, most of the alkaline earth oxides (BeO, MgO, CaO, and SrO), the column IIIB oxides (Sc2O3, Y2O3, and Re2O3, where Re is a rare earth), ThO2, UO2, ZrO2, HfO2, and Al2O3. Of these remaining oxides, sufficient data exist to conclude that BeO, MgO, and ZrO2 are thermodynamically stable in contact with silicon at 1000 K. Our results are consistent with reported investigations of silicon/binary oxide interfaces and identify candidate materials for future investigations.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400010384

Thermodynamic stability of binary oxides in contact With silicon

Part I: Background and Fundamentals Introduction, Mohamed Gad-el-Hak, University of Notre Dame Scaling of Micromechanical Devices, William Trimmer, Standard MEMS, Inc., and Robert H. Stroud, Aerospace Corporation Mechanical Properties of MEMS Materials, William N. Sharpe, Jr., Johns Hopkins University Flow Physics, Mohamed Gad-el-Hak, University of Notre Dame Integrated Simulation for MEMS: Coupling Flow-Structure-Thermal-Electrical Domains, Robert M. Kirby and George Em Karniadakis, Brown University, and Oleg Mikulchenko and Kartikeya Mayaram, Oregon State University Liquid Flows in Microchannels, Kendra V. Sharp and Ronald J. Adrian, University of Illinois at Urbana-Champaign, Juan G. Santiago and Joshua I. Molho, Stanford University Burnett Simulations of Flows in Microdevices, Ramesh K. Agarwal and Keon-Young Yun, Wichita State University Molecular-Based Microfluidic Simulation Models, Ali Beskok, Texas A&M University Lubrication in MEMS, Kenneth S. Breuer, Brown University Physics of Thin Liquid Films, Alexander Oron, Technion, Israel Bubble/Drop Transport in Microchannels, Hsueh-Chia Chang, University of Notre Dame Fundamentals of Control Theory, Bill Goodwine, University of Notre Dame Model-Based Flow Control for Distributed Architectures, Thomas R. Bewley, University of California, San Diego Soft Computing in Control, Mihir Sen and Bill Goodwine, University of Notre Dame Part II: Design and Fabrication Materials for Microelectromechanical Systems Christian A. Zorman and Mehran Mehregany, Case Western Reserve University MEMS Fabrication, Marc J. Madou, Nanogen, Inc. LIGA and Other Replication Techniques, Marc J. Madou, Nanogen, Inc. X-Ray-Based Fabrication, Todd Christenson, Sandia National Laboratories Electrochemical Fabrication (EFAB), Adam L. Cohen, MEMGen Corporation Fabrication and Characterization of Single-Crystal Silicon Carbide MEMS, Robert S. Okojie, NASA Glenn Research Center Deep Reactive Ion Etching for Bulk Micromachining of Silicon Carbide, Glenn M. Beheim, NASA Glenn Research Center Microfabricated Chemical Sensors for Aerospace Applications, Gary W. Hunter, NASA Glenn Research Center, Chung-Chiun Liu, Case Western Reserve University, and Darby B. Makel, Makel Engineering, Inc. Packaging of Harsh-Environment MEMS Devices, Liang-Yu Chen and Jih-Fen Lei, NASA Glenn Research Center Part III: Applications of MEMS Inertial Sensors, Paul L. Bergstrom, Michigan Technological University, and Gary G. Li, OMM, Inc. Micromachined Pressure Sensors, Jae-Sung Park, Chester Wilson, and Yogesh B. Gianchandani, University of Wisconsin-Madison Sensors and Actuators for Turbulent Flows. Lennart Loefdahl, Chalmers University of Technology, and Mohamed Gad-el-Hak, University of Notre Dame Surface-Micromachined Mechanisms, Andrew D. Oliver and David W. Plummer, Sandia National Laboratories Microrobotics Thorbjoern Ebefors and Goeran Stemme, Royal Institute of Technology, Sweden Microscale Vacuum Pumps, E. Phillip Muntz, University of Southern California, and Stephen E. Vargo, SiWave, Inc. Microdroplet Generators. Fan-Gang Tseng, National Tsing Hua University, Taiwan Micro Heat Pipes and Micro Heat Spreaders, G. P. "Bud" Peterson, Rensselaer Polytechnic Institute Microchannel Heat Sinks, Yitshak Zohar, Hong Kong University of Science and Technology Flow Control, Mohamed Gad-el-Hak, University of Notre Dame) Part IV: The Future Reactive Control for Skin-Friction Reduction, Haecheon Choi, Seoul National University Towards MEMS Autonomous Control of Free-Shear Flows, Ahmed Naguib, Michigan State University Fabrication Technologies for Nanoelectromechanical Systems, Gary H. Bernstein, Holly V. Goodson, and Gregory L. Snider, University of Notre Dame Index

The MEMS Handbook

The outstanding properties of SiO2, which include high resistivity, excellent dielectric strength, a large band gap, a high melting point, and a native, low defect density interface with Si, are in large part responsible for enabling the microelectronics revolution. The Si/SiO2 interface, which forms the heart of the modern metal–oxide–semiconductor field effect transistor, the building block of the integrated circuit, is arguably the worlds most economically and technologically important materials interface. This article summarizes recent progress and current scientific understanding of ultrathin (<4 nm) SiO2 and Si–O–N (silicon oxynitride) gate dielectrics on Si based devices. We will emphasize an understanding of the limits of these gate dielectrics, i.e., how their continuously shrinking thickness, dictated by integrated circuit device scaling, results in physical and electrical property changes that impose limits on their usefulness. We observe, in conclusion, that although Si microelectronic devices...

Ultrathin (<4 nm) SiO2 and Si-O-N gate dielectric layers for silicon microelectronics: Understanding the processing, structure, and physical and electrical limits

To date, the highest bulk lithium ion-conducting solid electrolyte is the perovskite (ABO3)-type lithium lanthanum titanate (LLT) Li3xLa(2/3)-x□(1/3)-2xTiO3 (0 < x < 0.16) and its related structure materials. The x ≈ 0.1 member exhibits conductivity of 1 × 10-3 S/cm at room temperature with an activation energy of 0.40 eV. The conductivity is comparable to that of commonly used polymer/liquid electrolytes. The ionic conductivity of LLT mainly depends on the size of the A-site ion cation (e.g., La or rare earth, alkali or alkaline earth), lithium and vacancy concentration, and the nature of the B−O bond. For example, replacement of La by other rare earth elements with smaller ionic radii than that of La decreases the lithium ion conductivity, while partial substitution of La by Sr (larger ionic radii than that of La) slightly increases the lithium ion conductivity. The high lithium ion conductivity of LLT is considered to be due to the large concentration of A-site vacancies, and the motion of lithium by a...

Lithium Lanthanum Titanates: A Review

Al3O3 thin film growth on Si(100) using binary reaction sequence chemistry

The microwave dielectric characteristics of ilmenite titanates, M2+TiO3 (where M2+=Ni, Mg and Mn) and ( Mg0.95 M0.052+)TiO3 (where M2+= Ni, Mg, Co and Mn) series, have been investigated as a function of ionic radius of M2+ and (Mg0.95 M0.052+)2+ ions, respectively. The ilmenite titanates have high Q value and low dielectric constant due to the isolation of TiO6 octahedra by the M O6 octahedron layer and cation vacancy layer in comparison with the perovskite titanates. The existence of localized 3d electrons in Ni2+(3 d8) and Mn2+(3 d5) is concerned with the microwave dielectric properties of the M2+ TiO3 series. The dielectric constant e r at 10 GHz of the (Mg0.95 M0.052+)TiO3 series shows the minimum value around the average ionic radius of 0.721 A, while the Q value shows a maximum, probably due to a local lattice distortion. The (Mg0.95Co0.05)TiO3 compound shows a maximum Q value of 23,000 at 10 GHz, dielectric constant of 16.8, and τ f of -54 ppm/K.

https://iopscience.iop.org/article/10.1143/JJAP.33.5466/pdf

Microwave Dielectric Characteristics of Ilmenite-Type Titanates with High Q Values

Heteroepitaxial Al2O3 films were grown successfully on (100)Si substrates at substrate temperatures above 1000 °C by low‐pressure chemical vapor deposition with the use of N2 bubbled Al(CH3)3 and N2O. From reflection high‐energy electron diffraction analysis, the epitaxial films were found to be γ‐Al2O3 with an orientation relation of (100)Al2O3//(100)Si. Capacitors with 700‐A‐thick Al2O3 films as gate insulators were fabricated and showed high‐frequency capacitance‐voltage characteristics without hysteresis. An interface state density of 1.7×1011 cm−2 eV−1 was observed by using quasistatic capacitance‐voltage measurements. The leakage current was 9.7×10−11 A/cm2 at a gate voltage of 3.0 V.

Epitaxial Al2O3 films on Si by low‐pressure chemical vapor deposition

A method to implement quaternary circuits using NMOS devices is proposed. The authors have designed a simplified elementary form of inverter and have implemented a series of fundamental logic and memory circuits. These circuits comprise MOS transistors with three values of enhancement-mode threshold voltage and one depletion-mode threshold voltage. The features of these circuits are a small number of MOS transistors, a simple structure, and an exact transfer characteristic. Several fundamental circuits such as inverter, NAND, NOR, and delta literal have been fabricated by conventional NMOS technology. Comparisons between the measured and calculated results indicate a good agreement, taking into account some back-bias effect. The performance of the inverter, including speed, noise margin, and pattern area, is also discussed.

Realization of quaternary logic circuits by n-channel MOS devices

Heteroepitaxial growth of γ‐Al2O3 films was performed successfully onto (100) and (111) Si substrates at low substrate temperatures between 720 and 800 °C by metalorganic molecular beam epitaxy using N2 bubbled Al(CH3)3 and N2O. Using in situ reflection high‐energy electron diffraction, the orientation relationships between epitaxial γ‐Al2O3 films and Si substrates were found to be (100) γ‐Al2O3//(100) Si with [110] γ‐Al2O3//[110] Si and (111) γ‐Al2O3//(111) Si with [112] γ‐Al2O3//[112] Si. The stoichiometry of the grown films was found similar to that of Al2O3 from Auger signals.

Metalorganic molecular beam epitaxy of γ‐Al2O3 films on Si at low growth temperatures

The (1-x)LaAlO3–xSrTiO3 solid solution system with the perovskite structure was synthesized and its dielectric behavior was investigated. The lattice parameter of (1-x)LaAlO3–xSrTiO3 increases with increasing the fraction of SrTiO3 in the system. 0.45LaAlO3–0.55SrTiO3 shows a dielectric constant e of 34, a temperature coefficient of resonant frequency τf of -8 ppmK-1 and a dielectric loss Q of 6900, which satisfy the suggested requirements for applications to mobile communications devices. The annihilation of the ferroelectric mode of SrTiO3 corresponds to the drastic decrease of e and τf of SrTiO3 to those of 0.25LaAlO3–0.75SrTiO3.

https://iopscience.iop.org/article/10.1143/JJAP.37.5625/pdf

Tetsuro Nakamura

Papers

Microwave Dielectric Characteristics of Ilmenite-Type Titanates with High Q Values

Epitaxial Al2O3 films on Si by low‐pressure chemical vapor deposition

Realization of quaternary logic circuits by n-channel MOS devices

Metalorganic molecular beam epitaxy of γ‐Al2O3 films on Si at low growth temperatures

Dielectric Behavior of (1-x)LaAlO3–xSrTiO3 Solid Solution System at Microwave Frequencies