Vertical Thyristor Epitaxial Structure With Integrated FETs

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Solution Overview

Problem

Conventional IGBTs face limitations in switching frequency due to the accumulation of holes in the N− drift region, which restricts their suitability for high-frequency applications, and existing gate drive circuitry may not provide adequate electrical isolation efficiently.

Innovation Solution

A semiconductor device with a thyristor epitaxial layer structure and integrated field effect transistors, utilizing a common modulation doped QW structure, allows for optical signal-controlled switching between conducting and non-conducting states, enhancing switching frequency and incorporating epitaxial resistive regions for voltage protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional IGBT structure is used, then high power capability is achieved, but switching frequency is limited due to hole accumulation in N- drift region

Engineering Contradiction:

Improveswitching frequencyVSAvoidhole accumulation effect

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The device is segmented into two main functional parts: a thyristor epitaxial layer structure for high-power conduction and integrated field effect transistors for switching control. This segmentation allows the high-power thyristor structure to operate without the hole accumulation limitations that constrain conventional IGBTs, while the FETs provide fast switching capability independently of the drift region hole dynamics

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges a thyristor epitaxial layer structure with integrated field effect transistors to create a hybrid device. The thyristor structure provides high-power capability without hole accumulation limitations, while the FETs provide voltage-controlled switching. This combination achieves both high power capability and high switching frequency that neither structure could achieve alone

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If conventional gate drive circuitry is used, then electrical isolation is provided, but isolation efficiency is inadequate for high-frequency applications

Engineering Contradiction:

Improveelectrical isolation efficiencyVSAvoidswitching frequency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces conventional electrical gate drive circuitry with optical control mechanisms. Optical signals are used to control the integrated field effect transistors, providing superior electrical isolation between the control circuit and power circuit. This optical control method eliminates the limitations of conventional electrical isolation while maintaining high-frequency switching capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If high voltage operation is implemented, then power capability is increased, but voltage breakdown risk increases

Engineering Contradiction:

Improvepower capabilityVSAvoidvoltage breakdown

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates epitaxial resistive regions that are formed during the epitaxial growth process. These resistive regions are positioned to provide voltage protection before breakdown can occur. The resistive regions dissipate excessive voltage stress and protect the high-power thyristor structure from voltage breakdown, enabling safe high-voltage operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 semiconductor device achieves improved switching frequencies and efficient electrical isolation, enabling high-power applications with reduced voltage breakdown risks, thus overcoming the limitations of conventional IGBTs.

Implementation Method 1

A first field effect transistor having a channel for current flow therethrough is integrally formed on the substrate together with the thyristor epitaxial layer structure

Methodology Applied

Scientific EffectField effect transistor channel control:

Implementation Method 2

An epitaxial resistive region is electrically coupled to and extends laterally from a particular one of the plurality of intermediate regions

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentUS9276160B2Power semiconductor device formed from a vertical thyristor epitaxial layer structure

Publication Date: 2016.03.01 OPEL SOLAR INC

AI summary

A semiconductor device suitable for power applications includes a thyristor epitaxial layer structure defining an anode region offset vertically from a cathode region with a plurality of intermediate regions therebetween. An anode electrode is electrically coupled to the anode region. A cathode electrode is electrically coupled to the cathode region. A switchable current path that extends vertically between the anode region and the cathode region has a conducting state and a non-conducting state. An epitaxial resistive region is electrically coupled to and extends laterally from one of the plurality of intermediate regions. An FET is provided having a channel that is electrically coupled to the epitaxial resistive region. The FET can be configured to inject (or remove) electrical carriers into (or from) the one intermediate region via the epitaxial resistive region in order to switch the switchable current path between its non-conducting state and its conducting state.