Computer-aided-design (CAD) of semiconductor microtransducers is
relatively new in contrast to their counterparts in the integrated
circuit world. Integrated silicon microtransducers are realized using
microfabrication techniques similar to those for standard integrated
circuits (ICs). Unlike IC devices, however, microtransducers must
interact with their environment, so their numerical simulation is
considerably more complex. While the design of ICs aims at suppressing
"parasitic" effects, microtransducers thrive on optimizing the one or
the other such effect. The challenging quest for physical models and
simulation tools enabling microtransducer CAD is the topic of this book.
It is intended as a text for graduate students in Electrical Engineering
and Physics and as a reference for CAD engineers in the microsystems
industry. This text evolved from a series of courses offered to graduate
students from Electrical Engineering and Physics. Much of the material
in the book can be presented in about 40 hours of lecture time. The book
starts with an illustrative example which highlights the goals and
benefits of microtransducer CAD. This follows with a summary of model
equations describing electrical transport in semiconductor devices and
microtransducers in the absence of external fields. Models treating the
effects of the external radiant, magnetic, thermal, and mechanical
fields on electrical transport are then systematically introduced. To
enable a smooth transition into modeling of mechanical systems, an
abridged version of solid structural and fluid mechanics is presented,
whereby the focus is on pertinent model equations and boundary
conditions. This follows with model equations and boundary conditions
relevant to various types of mechanical microactuators including
electrostatic, thermal, magnetic, piezoelectric, and electroacoustic.
The book concludes with a glimpse into SPICE simulation of the
mixed-signal microsystem, i.e., microtransducer plus circuitry. Where
possible, the model equations are supplemented with tables and/or graphs
of process-dependent material data to enable the CAD engineer to carry
out simulations even when reliable material models are not available.
IVZ LANG: Introduction: Modeling and Simulation of Microtransducers;
Illustrative Example; Progress in Microtransducer Modeling; References.-
Basic Electronic Transport: Poisson's Equation; Continuity Equations;
Carrier Transport in Crystalline Materials and Isothermal Behavior;
Electrical Conductivity and Isothermal Behavior in Polycrystalline
Materials; Electrical Conductivity and Isothermal Behavior in Metals;
Boundary and Interface Conditions; The External Fields - What Do They
Influence?; References.- Radiation Effects on Carrier Transport:
Reflection and Transmission of Optical Signals; Modeling Optical
Absorption in Intrinsic Semiconductors; Absorption in Heavily-Doped
Semiconductors; Optical Generation Rate and Quantum Efficiency; Low
Energy Interactions with Insulators and Metals; High Energy Interactions
and Monte Carlo Simulations; Model Equations for Radiant Sensor
Simulation; Illustrative Simulation Example - Color Sensor; References.-
Magnetic-Field Effects on Carrier Transport: Galvanomagnetic Transport
Equation; Galvanomagnetic Transport Coefficients; Equations and Boundary
Conditions for Magnetic Sensor Simulation; Illustrative Simulation
Example - Micromachined Magnetic Vector Probe; References.- Thermal
Non-Uniformity Effects on Carrier Transport: Non-Isothermal Effects;
Electrothermal Transport Model; Electrical and Thermal Transport
Coefficients; Electro-Thermo-Magnetic Interactions; Heat Transfer in
Thermal Microstructures; Summary of Equations and Computational
Procedure; Illustrative Simulation Example - Micro Pirani Gauge;
References.- Mechanical Effects on Carrier Transport: Piezoresistive
Effect; Strain and Electron Transport; Strain and Hole Transport;
Piezojunction Effect; Effects of Stress Gradients;
Galvano-Piezo-Magnetic Effects; The Piezo Drift-Diffusion Transport
Model; Illustrative Simulation Example - Stress Effects on Hall Sensors;
References.- Mechanical and Fluidic Signals: Definitions; Model
Equations for Mechanical Analysis; Model Equations for Analysis of Fluid
Transport; Illustrative Simulation Example - Analysis of Flow Channels;
References.- Micro-Actuation: Transduction Principles; State-of-the-Art
and Preview; Electrostatic Actuation; Thermal Actuation; Magnetic
Actuation; Piezoelectric Actuation; Electroacoustic Transducers;
Computational Procedure and Coupling; Illustrative Example - CMOS
Micromirror.- Microsystem Simulation: Electrical Analogues for
Mixed-Signals and Historical Developments; Circuit Modeling and
Implementation Considerations; Lumped Analysis: Illustrative Example -
Electrostatic Micromirror; Distributed Analysis: Illustrative Example -
Flow Microsensor; References.- Subject Index.
