Self-Triggering Gated Thyristor ESD Protection
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Solution Overview
Problem
Existing electrostatic discharge (ESD) protection devices require multiple components and complex triggering circuits, leading to instability and increased surface occupation, especially in gated thyristor designs.
Innovation Solution
A self-triggering gated thyristor design with nested bipolar transistors and an MOS transistor, where the base region of the second bipolar transistor acts as a resistive semiconductor region connected to the cathode, allowing internal resistive-capacitive triggering without external circuits, fabricated using silicon-on-insulator technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a gated thyristor is used to reduce component count, then the number of components decreases, but stability deteriorates and external triggering circuits are required
Solution Approach 1:
The patent merges the triggering function with the thyristor structure by integrating an MOS transistor and resistive semiconductor region directly into the thyristor. This combination eliminates the need for external triggering circuits while maintaining stability, as the triggering components are now part of the thyristor itself rather than separate external elements.
Solution Approach 2:
The thyristor is designed to be self-triggering through the integrated MOS transistor and resistive semiconductor region that automatically respond to ESD pulses. The device serves its own triggering needs without requiring external control circuits, achieving both component reduction and stability by making the triggering function inherent to the thyristor structure.
2Reliability
If external triggering circuits are added to ensure stability, then reliability improves, but device complexity and surface area increase
Solution Approach 1:
The triggering function is merged with the thyristor by integrating the MOS transistor and resistive semiconductor region within the thyristor structure. This eliminates separate external triggering circuits, reducing device complexity while maintaining stability through the integrated design.
Solution Approach 2:
The MOS transistor and resistive semiconductor region are nested within the thyristor structure, with the MOS transistor gate connected to the cathode through the resistive region. This nesting approach allows the triggering components to be housed within the thyristor itself, reducing overall device complexity and surface area while ensuring stable operation.
3Reliability
If external triggering circuits are used, then the thyristor can be triggered reliably, but surface area occupation increases
Solution Approach 1:
The triggering components (MOS transistor and resistive semiconductor region) are merged with the thyristor structure, eliminating the need for separate external triggering circuits. This integration significantly reduces the total surface area while maintaining reliable triggering through the compact integrated design.
Solution Approach 2:
The MOS transistor and resistive semiconductor region are nested within the thyristor structure, with the MOS transistor gate connected to the cathode through the resistive region that is part of the thyristor's base region. This nesting minimizes surface area occupation while ensuring reliable triggering functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces component count, enhances stability, and minimizes surface area occupation by enabling self-triggering during ESD pulses while maintaining stability during normal operation, effectively protecting electronic components from bidirectional ESDs.
Implementation Method 1
this base region of the second bipolar transistor, which is situated on the cathode side and which is also the substrate region of the MOS transistor, offers an intrinsic resistance which, with the reverse capacitive NP junction between the base regions of the two bipolar transistors, allows the thyristor to be triggered when an ESD pulse occurs
Implementation Method 2
allows the thyristor to be triggered when an ESD pulse occurs propagating from the anode towards the cathode
Implementation Method 3
the reverse capacitive NP junction between the base regions of the two bipolar transistors
Data Source
AI summary
A semiconductor device includes a thyristor disposed in a semiconductor body. The thyristor has an anode, a cathode, a first bipolar transistor located on an anode side, and a second bipolar transistor located on a cathode side. The first and second bipolar transistors are nested and connected between the anode and the cathode. A MOS transistor is disposed in the semiconductor body. The MOS transistor is coupled between a collector region and an emitter region of the second bipolar transistor. The MOS transistor has a gate region connected to the cathode via a resistive semiconductor region that incorporates at least a part of a base region of the second bipolar transistor.