Semiconductor Apparatus Diode Gate Resistor dV/dt Control

Solution Overview

Problem

Conventional semiconductor apparatuses with active dummy trench gates connected to the gate terminal experience increased parasitic capacitance, leading to excessive dV/dt and reduced controllability of the gate resistor during IGBT turn-on, due to current charging capacitance between the gate and emitter without passing through the gate resistor.

Innovation Solution

Incorporating a diode between the active and dummy trench gate electrodes, connected to the gate and emitter terminals, respectively, to prevent displacement current from charging the parasitic capacitance, thereby controlling dV/dt through the gate resistor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If active dummy trench gates are connected to the gate terminal, then gate resistance is decreased and dV/dt controllability is improved, but parasitic capacitance increases causing excessive current flow and reduced controllability

Engineering Contradiction:

ImprovedV/dt controllabilityVSAvoidcontrollability precision

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The gate terminal connections are segmented into two groups: active trench gates connected to gate terminal G and dummy trench gates connected to gate terminal GD. This segmentation allows independent control of the two gate types, preventing the parasitic capacitance of dummy gates from affecting the dV/dt controllability of active gates while still providing the benefits of dummy gate connections.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An isolation circuit is introduced as an intermediary between the dummy trench gates and the gate terminal. This isolation circuit prevents the parasitic capacitance of dummy gates from directly affecting the gate resistor's ability to control dV/dt, while still allowing the dummy gates to be connected to a gate terminal for potential activation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If active dummy trench gates are connected to the gate terminal, then gate resistance is decreased, but parasitic capacitance causes excessive current flow charging gate-emitter capacitance without passing through gate resistor

Engineering Contradiction:

Improvegate resistanceVSAvoidexcessive current flow

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The gate terminal connections are segmented into two groups: active trench gates connected to gate terminal G and dummy trench gates connected to gate terminal GD. This segmentation allows independent control of the two gate types, preventing the parasitic capacitance of dummy gates from affecting the dV/dt controllability of active gates while still providing the benefits of dummy gate connections.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An isolation circuit is introduced as an intermediary between the dummy trench gates and the gate terminal. This isolation circuit prevents the parasitic capacitance of dummy gates from directly affecting the gate resistor's ability to control dV/dt, while still allowing the dummy gates to be connected to a gate terminal for potential activation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If dummy trench gates are connected to emitter terminal, then parasitic capacitance is reduced, but gate resistance cannot be decreased effectively

Engineering Contradiction:

Improveparasitic capacitance controlVSAvoidgate resistance

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The gate terminal connections are segmented into two groups: active trench gates connected to gate terminal G and dummy trench gates connected to gate terminal GD. This segmentation allows independent control of the two gate types, preventing the parasitic capacitance of dummy gates from affecting the dV/dt controllability of active gates while still providing the benefits of dummy gate connections.

Inventive Principle:

Principle #1Segmentation

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

This configuration enhances the controllability of dV/dt by preventing excessive current flow and reducing conduction losses, improving the reliability and energy efficiency of the semiconductor apparatus.

Implementation Method 1

a diode whose anode side and cathode side are electrically connected to the trench gate electrode and the dummy trench gate electrodes respectively

Methodology Applied

Scientific EffectDiode rectification: Diode

Data Source

PatentUS10192978B2Semiconductor apparatus

Publication Date: 2019.01.29 MITSUBISHI ELECTRIC CORP

AI summary

A semiconductor apparatus includes: a p-type base layer provided on a top surface side of an n-type drift layer; an n-type emitter layer provided on a top surface side of the p-type base layer; a first control electrode having a trench gate electrode embedded so as to reach from a surface layer of the n-type emitter layer to the n-type drift layer; a second control electrode having a trench gate electrode embedded so as to reach from the p-type base layer to the n-type drift layer; a p-type collector layer provided on a bottom surface side of the n-type drift layer; and a diode whose anode side and cathode side are connected to the first control electrode and the second control electrodes, respectively. It is possible to improve the controllability of dV/dt by a gate resistor.