MPS Diode Layout With Floating P-Regions for Lower Leakage

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Solution Overview

Problem

Wide bandgap semiconductor rectifying devices, such as JBS diodes, suffer from reverse current leakage due to large Schottky contact areas, which deteriorates forward voltage characteristics.

Innovation Solution

A merged PiN Schottky (MPS) diode design featuring floating doped regions around biased doped regions with a Schottky metal layer, where the first portions of the doped regions are electrically floating and the second portions are connected to the top metal, reducing current leakage and improving forward voltage characteristics by preventing depletion regions and increasing Schottky contact area without increasing leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the Schottky contact area is increased to improve reverse blocking voltage, then reverse blocking capability is improved, but reverse current leakage increases and forward voltage characteristics deteriorate

Engineering Contradiction:

Improvereverse blocking voltageVSAvoidreverse current leakage

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The doped regions are divided into multiple discrete portions (first portions and second portions) rather than continuous regions. This segmentation allows the Schottky contact to interact with multiple separated doped regions, increasing effective contact area while the gaps between portions prevent continuous depletion region formation that would cause leakage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the doped regions have different electrical characteristics - first portions are electrically floating while second portions are electrically connected to the Schottky contact. This local differentiation allows specific areas to serve different functions: floating portions prevent depletion penetration while connected portions provide rectifying contact.

Inventive Principle:

Principle #3Local quality

2Strength

If floating doped regions are introduced to prevent depletion region penetration, then reverse blocking voltage is maintained, but device structure complexity increases

Engineering Contradiction:

Improvereverse blocking voltageVSAvoiddoped region structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The floating doped regions and Schottky contact structure are merged into a unified device architecture where the same doped regions serve dual purposes: providing rectifying contact when connected and preventing depletion penetration when floating. This integration avoids adding separate components and reduces overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The doped regions perform multiple functions simultaneously - they provide the rectifying Schottky contact interface, create barriers to depletion region penetration, and maintain reverse blocking voltage. This multi-functionality eliminates the need for separate structures and reduces device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 MPS diode effectively reduces current leakage and enhances forward voltage characteristics by utilizing floating doped regions to prevent electric field penetration and maintain high reverse blocking voltage, while allowing for larger Schottky contact areas without increased leakage.

Implementation Method 1

a Schottky barrier diode (SBD) having a carrier potential barrier of a difference in work function between a semiconductor layer and metal

Methodology Applied

Scientific EffectSchottky barrier:

Implementation Method 2

the first portions of the doped regions are electrically floating... floating doped regions to prevent electric field penetration and maintain high reverse blocking voltage

Methodology Applied

Scientific EffectElectric field blocking: Electric Field

Implementation Method 3

The Schottky metal layer is conformally deposited on the second epitaxial layer and the exposed second portions of the doped regions

Methodology Applied

Scientific EffectConformal deposition: Deposition (physical)

Data Source

PatentUS12191403B2Method of manufacturing merged PiN Schottky (MPS) diode

Publication Date: 2025.01.07 LEAP SEMICON CORP

AI summary

A merged PiN Schottky (MPS) diode includes a substrate, a first epitaxial layer of a first conductivity type, doped regions of a second conductivity type, a second epitaxial layer of the first conductivity type, and a Schottky metal layer. The first epitaxial layer is disposed on the first surface of the substrate. The doped regions are disposed in a surface of the first epitaxial layer, wherein the doped regions consist of first portions and second portions, the first portions are electrically floating, and the second portions are electrically connected to a top metal. The second epitaxial layer is disposed on the surface of the first epitaxial layer, wherein trenches are formed in the second epitaxial layer to expose the second portions of the doped regions. The Schottky metal layer is conformally deposited on the second epitaxial layer and the exposed second portions of the doped regions.