Schottky Barrier Edge Modification for Leakage Reduction

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Solution Overview

Problem

Heterojunction semiconductor devices face high leakage current issues in the off-state due to the edge effect at the gate edge, where the electric field accumulates, leading to increased current flow, which existing solutions like fluorine-doped back barriers negatively impact on-state characteristics.

Innovation Solution

A conductive barrier portion is introduced underneath the edge region of the Schottky electrode to incrementally increase the Schottky barrier, spatially separating the current path from the electric field accumulation, reducing leakage current without compromising on-state performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a fluorine-doped enhanced back barrier is provided underneath the Schottky gate to reduce leakage current, then leakage current in off-state is reduced, but on-characteristics of the device are negatively influenced

Engineering Contradiction:
Improveleakage currentVSAvoidon-characteristics
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by introducing a conductive barrier portion only underneath the edge region of the Schottky electrode, rather than uniformly doping the entire back barrier. This localized approach increases the Schottky barrier specifically at the gate edge where leakage occurs due to electric field accumulation, while leaving the central region unchanged to preserve strong on-state characteristics and high electron mobility.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The Schottky electrode is segmented into a central region and an edge region, with the conductive barrier portion applied only to the edge region. This segmentation allows differential treatment of areas with different functional requirements: the central region maintains low barrier for high current flow in on-state, while the edge region gets enhanced barrier to suppress leakage in off-state.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If the Schottky barrier is increased at the gate edge to reduce leakage current, then leakage current is reduced, but the uniformity of the barrier is compromised

Engineering Contradiction:
Improveleakage currentVSAvoidbarrier uniformity
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent deliberately creates non-uniform barrier composition by adding a conductive barrier portion only in the edge region. This local modification accepts reduced overall uniformity to achieve the specific goal of suppressing edge-related leakage current while maintaining appropriate barrier characteristics in the central region for optimal device performance.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If a conductive barrier portion is introduced underneath the edge region to locally increase the Schottky barrier, then leakage current is reduced without compromising on-state performance, but device complexity increases

Engineering Contradiction:
Improveleakage currentVSAvoidstructure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces a conductive barrier portion only in the edge region underneath the Schottky electrode, creating a localized modification rather than a global structural change. This approach reduces leakage current at the critical edge region while maintaining the simplicity of the overall device structure and avoiding complex multi-layer or multi-component designs.

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

This approach significantly reduces leakage current in the off-state by increasing the Schottky barrier locally at the gate edge, thereby minimizing the impact on on-state characteristics, enhancing the device's overall performance.

Implementation Method 1

there is often no dopant required in the AIGaN layer due to the strong spontaneous and piezoelectric polarization effect in such systems

Methodology Applied
Scientific EffectSpontaneous polarization: Polarisation

Implementation Method 2

there is often no dopant required in the AIGaN layer due to the strong spontaneous and piezoelectric polarization effect in such systems

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

a Schottky electrode and a first further electrode each conductively coupled to a different area of the heterojunction

Methodology Applied
Scientific EffectSchottky barrier formation: Conduction (electrical)

Data Source

PatentEP2667415B1Heterojunction semiconductor device and manufacturing method
Publication Date: 2021.02.17 NEXPERIA BV
  • EP2667415B1 patent drawingFigure 1~2
  • EP2667415B1 patent drawingFigure 3~4
  • EP2667415B1 patent drawingFigure 5~6

AI summary

Disclosed is a semiconductor device comprising a group 13 nitride heterojunction comprising a first layer having a first bandgap and a second layer having a second bandgap, wherein the first layer is located between a substrate and the second layer; and a Schottky electrode and a first further electrode each conductively coupled to a different area of the heterojunction, said Schottky electrode comprising a central region and an edge region, wherein the element comprises a conductive barrier portion located underneath said edge region only of the Schottky electrode for locally increasing the Schottky barrier of the Schottky electrode. A method of manufacturing such a semiconductor device is also disclosed.