Optically Triggered Silicon Thyristor With Trench Isolation

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Solution Overview

Problem

Thyristors, particularly silicon controlled switches, face challenges in being triggered efficiently without requiring continuous trigger current, and existing optical triggering methods often rely on external compound semiconductor sources, which may not be integrated seamlessly with silicon-based systems.

Innovation Solution

An optically triggered switch is designed with a silicon layer containing a trench and a silicon diode that generates electromagnetic radiation to trigger a physically and electrically isolated thyristor, allowing the switch to turn on without continuous current, utilizing mechanisms like p-n junction diodes and trench isolation for efficient triggering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If external compound semiconductor optical sources are used to trigger the thyristor, then the thyristor can be triggered optically, but the integration with silicon-based systems is poor and device complexity increases

Engineering Contradiction:

Improveintegration with silicon-based systemsVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses a silicon diode instead of compound semiconductor to generate the optical trigger signal, maintaining material homogeneity throughout the device. All components (silicon diode, silicon layer, thyristor) are made of silicon or silicon-based materials, enabling seamless integration with silicon-based systems and eliminating the need for complex heterostructure interfaces.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent combines the optical trigger generation function and the switching function into a single integrated device structure. The silicon diode that generates electromagnetic radiation is formed in the same silicon layer as the thyristor, with both functions merged into one compact device rather than requiring separate external optical sources and switches.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If a trench is formed to physically and electrically isolate the silicon diode from the thyristor, then electrical isolation is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveelectrical isolationVSAvoidtrench formation precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a trench as an intermediary structure between the silicon diode and the thyristor. This trench physically and electrically isolates the two components while allowing them to remain in the same silicon layer. The trench acts as a mediator that provides the necessary isolation without requiring the components to be completely separate devices, thus balancing isolation requirements with manufacturing feasibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If continuous trigger current is used to maintain the thyristor in the on state, then the thyristor remains reliably on, but energy consumption increases

Engineering Contradiction:

Improveswitching reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic electromagnetic radiation pulses from the silicon diode to trigger the thyristor into the on state, rather than requiring continuous trigger current. Once triggered, the thyristor maintains its on state through its inherent latching mechanism, consuming minimal holding current. The periodic optical pulses replace the need for continuous external triggering, significantly reducing energy consumption while maintaining reliable switching.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent substitutes the electrical trigger current mechanism with an optical trigger mechanism using electromagnetic radiation from a silicon diode. This replacement eliminates the need for continuous electrical triggering and reduces the energy required to maintain the on state, as the optical trigger only needs to provide the initial latching current pulse rather than continuous current.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables a thyristor to be triggered by electromagnetic radiation generated within the silicon layer, improving switching efficiency and integration within silicon-based systems, reducing the need for external trigger sources and continuous current.

Implementation Method 1

at least one silicon diode formed in the silicon layer... configured to turn on in response to electromagnetic radiation generated by the silicon diode

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS8012775B2Method of forming a light activated silicon controlled switch

Publication Date: 2011.09.06 MICROSEMI SEMICONDUCTOR US INC

AI summary

The present invention provides a method of forming an optically triggered switch. Embodiments of the method include forming a silicon layer, forming one or more trenches in the silicon layer, and forming one or more silicon diodes in the silicon layer. Embodiments of the method also include forming a first thyristor in the silicon layer such that the first thyristor is physically and electrically isolated from the silicon diode(s) by the trench(es). The first thyristor is configured to turn on in response to electromagnetic radiation generated by the silicon diode(s).