Schottky Diode Layout for Surge Current and Thermal Damage Control

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Solution Overview

Problem

Schottky barrier diodes (SBDs) using silicon carbide face challenges in surge current tolerance, leading to potential thermal destruction due to uneven current distribution and high current density under the bonding member.

Innovation Solution

A semiconductor device design with a higher area ratio of conductive members under the bonding member compared to other regions, along with strategically arranged island-shaped p-i-n regions and a Schottky junction, enhances surge current handling by concentrating current effectively and reducing thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a p-n junction diode is provided inside the SBD to increase surge current tolerance, then surge current tolerance is improved, but current density becomes uneven and thermal destruction occurs under the bonding member

Engineering Contradiction:
Improvesurge current toleranceVSAvoidthermal destruction
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating different conductive member configurations in different regions of the semiconductor device. Specifically, the first conductive members are positioned to have a first area ratio in a first region, while the second conductive members have a second area ratio in a second region, where the area ratios differ. This non-uniform distribution optimizes current density distribution locally to prevent thermal destruction while maintaining surge current tolerance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of conductive member area ratio to resolve the contradiction. By adjusting the area ratio of conductive members in different regions, the patent optimizes current distribution to prevent both thermal destruction and maintain surge current tolerance. The area ratio serves as a controllable parameter to balance competing requirements.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conductive members are uniformly distributed, then manufacturing is simplified, but current density becomes uneven leading to thermal destruction

Engineering Contradiction:
Improveconductive member distributionVSAvoidthermal destruction
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent transitions from uniform to non-uniform conductive member distribution by implementing different area ratios in different regions. This local differentiation optimizes current density distribution to prevent thermal destruction while maintaining reasonable manufacturing complexity through systematic regional classification.

Inventive Principle:
Principle #3Local quality

3Reliability

If the area ratio of conductive members is increased under the bonding member, then surge current handling is improved, but device complexity increases

Engineering Contradiction:
Improvesurge current handlingVSAvoidconductive member configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements local quality by dividing the device into distinct regions (first region and second region) with different conductive member area ratios. This regional differentiation targets surge current handling optimization specifically where needed under the bonding member while maintaining simpler configurations elsewhere, balancing performance improvement with device complexity.

Inventive Principle:
Principle #3Local quality

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 design effectively manages surge currents, suppressing damage to the semiconductor device while maintaining low forward voltage in normal operation by optimizing current flow and distribution.

Implementation Method 1

a metal layer located on the first semiconductor layer and on the second semiconductor layer, the metal layer having a Schottky junction with the first semiconductor layer

Methodology Applied
Scientific EffectSchottky junction:

Implementation Method 2

a conductive member located between the second semiconductor layer and the metal layer, the conductive member being made of a different material from the metal layer

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

enhances surge current handling by concentrating current effectively and reducing thermal damage

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4343848A1Semiconductor device
Publication Date: 2024.03.27 KK TOSHIBA
  • EP4343848A1 patent drawingFigure 1
  • EP4343848A1 patent drawingFigure 2
  • EP4343848A1 patent drawingFigure 3

AI summary

A semiconductor device includes a first electrode, a first semiconductor layer of a first conductivity type located on the first electrode, a second semiconductor layer of a second conductivity type located on a portion of the first semiconductor layer, a metal layer located on the first and second semiconductor layers, a second electrode located on the metal layer, a bonding member connected to an upper surface of the second electrode, and a conductive member located between the second semiconductor layer and the metal layer. The metal layer has a Schottky junction with the first semiconductor layer. The conductive member is made of a different material from the metal layer. An area ratio of the conductive member in a region directly under the bonding member is higher than an area ratio of the conductive member in a region other than the region directly under the bonding member.