Clear methodologies that grant protection from latchup, with insight into the physics, technology and circuit issues involved, are in increasing demand.
This book describes CMOS and BiCMOS semiconductor technology and their sensitivity to present day latchup phenomena, from basic over–voltage and over–current conditions, single event latchup (SEL) and cable discharge events (CDE), to latchup domino phenomena. It contains chapters focusing on bipolar physics, latchup theory, latchup and guard ring characterization structures, characterization testing, product level test systems, product level testing and experimental results. Discussions on state–of–the–art semiconductor processes, design layout, and circuit level and system level latchup solutions are also included, as well as:
- latchup semiconductor process solutions for both CMOS to BiCMOS, such as shallow trench, deep trench, retrograde wells, connecting implants, sub–collectors, heavily–doped buried layers, and buried grids from single– to triple–well CMOS;
- practical latchup design methods, automated and bench–level latchup testing methods and techniques, latchup theory of logarithm resistance space, generalized alpha (a) space, beta (b) space, new latchup design methods connecting the theoretical to the practical analysis, and;
- examples of latchup computer aided design (CAD) methodologies, from design rule checking (DRC) and logical–to–physical design, to new latchup CAD methodologies that address latchup for internal and external latchup on a local as well as global design level.
Latchup acts as a companion text to the author s series of books on ESD (electrostatic discharge) protection, serving as an invaluable reference for the professional semiconductor chip and system–level ESD engineer. Semiconductor device, process and circuit designers, and quality, reliability and failure analysis engineers will find it informative on the issues that confront modern CMOS technology. Practitioners in the automotive and aerospace industries will also find it useful. In addition, its academic treatment will appeal to both senior and graduate students with interests in semiconductor process, device physics, computer aided design and design integration.
Chapter 1 CMOS Latchup.
1.1 CMOS Latchup.
1.2 Fundamental Concepts of Latchup Design Practice.
1.3 Building a CMOS Latchup Strategy.
1.4 CMOS Latchup Technology Migration Strategy.
1.5 Key Metrics of Latchup Design Practice.
1.6 CMOS Latchup Technology Trends and Scaling.
1.7 Key Developments.
1.8 Latchup Failure Mechanisms.
1.9 CMOS Latchup Events.
1.10 Electrostatic Discharge Sources.
1.11 Single Event Latchup.
1.12 Summary and Closing Comments.
Chapter 2 Bipolar Transistors.
2.1 The Bipolar Transistor and CMOS Latchup.
2.2 Bipolar Transistor.
2.3 Recombination Mechanisms.
2.4 Photon Currents in Metallurgical Junctions.
2.5 Avalanche Breakdown.
2.6 Vertical Bipolar Transistor Model.
2.7 Lateral Bipolar Transistor Models.
2.8 Lateral Bipolar Transistor Models with Electric Field Assist.
2.9 Lateral Bipolar Transistor Models Nonuniform Vertical Profile.
2.10 Triple–Well Bipolar Transistor Models Lateral and Vertical Contributions.
2.11 Merged Triple–Well Bipolar Models.
2.12 Summary and Closing Comments.
Chapter 3 Latchup Theory.
3.1 Regenerative Feedback.
3.1.1 Regenerative Feedback without Shunt Resistors and Alpha Representation.
3.2 Latchup Criterion with Emitter Resistance.
3.3 Holding Point Conditions.
3.4 Resistance Space.
3.5 Beta Space.
3.6 CMOS Latchup Differential Tetrode Condition.
3.7 CMOS Latchup Differential Holding Current Relationship.
3.8 CMOS Latchup Differential Holding Voltage Relationship.
3.9 CMOS Latchup Differential Resistance Relationship.
3.10 Differential Generalized Alpha Space Relationship.
3.11 High–Level Injection.
3.12 Transient Latchup.
3.13 External Latchup.
3.14 Alpha Particle Induced Latchup.
3.15 Summary and Closing Comments.
Chapter 4 Latchup Structures, Characterization and Test.
4.1 Guard Rings.
4.2 Latchup Characterization Structures Single– and Dual–Well CMOS PNPN Test Structures.
4.3 Latchup Characterization Basic Triple–Well pnpn Latchup Test Structures.
4.4 Latchup Characterization Techniques pnpn Structures with Deep Trench.
4.5 Latchup Characterization and Testing Nonautomated Test Systems and Methodology.
4.6 Latchup Characterization and Testing Automatic Test Systems.
4.7 Latchup Characterization Wafer–Level Test Procedures.
4.8 Latchup Characterization Techniques Wafer–level Transmission Line Pulse Methodology.
4.9 Latchup Characterization Transient Latchup.
4.10 Guard Ring Characterization.
4.11 Latchup Failure Analysis Techniques.
4.12 Summary and Closing Comments.
Chapter 5 CMOS Latchup Process Features and Solutions Dual–Well and Triple–Well CMOS.
5.1 CMOS Semiconductor Process Solutions and CMOS Latchup.
5.5 pþ/nþ Scaling.
5.6 Isolation and Latchup.
5.8 Triple Well.
5.9 High–Dose Buried Layer.
5.10 Future Concepts.
5.11 Summary and Closing Comments.
Chapter 6 CMOS Latchup Process Features and Solutions Bipolar and BiCMOS Technology.
6.1 CMOS Latchup in Bipolar and RF BiCMOS Technology.
6.2 Substrates High–Resistance Substrates.
6.4 Alternative Isolation Concepts.
6.5 Trench Isolation (TI).
6.6 Deep Trench.
6.7 Triple–Well and BiCMOS Processes Integration.
6.8 Heavily Doped Buried Layer Implant and BiCMOS Technology.
6.9 Summary and Closing Comments.
Chapter 7 CMOS Latchup Circuits.
7.1 Table of Circuit Interactions.
7.2 Intrabook Latchup Mechanisms.
7.3 Interbook Latchup Mechanisms.
7.4 Circuit Solutions Input Circuit.
7.5 Power Supply Concepts.
7.6 Latchup Circuit Solutions Power Supply to Power Supply Sequencing Circuitry.
7.7 Overshoot and Undershoot Clamp Networks.
7.8 Passive and Active Guard Rings.
7.9 Triple–Well Noise and Latchup Suppression Structures.
7.10 System–Level Issues.
7.11 Summary and Closing Comments.
Chapter 8 Latchup Computer Aided Design (CAD) Methods.
8.1 Latchup CAD Rules.
8.2 Design Rule Checking.
8.3 Computer–Aided Design Extraction Methodologies Searching for the pnpn.
8.4 CAD Extraction Methods Searching for the Guard Rings.
8.5 Latchup Extraction Methods and Tools.
8.6 Latchup CAD Simulation.
8.7 Summary and Closing Comments.