Monolithic III-Nitride Vertical-Lateral Integration Without Wafer Bonding

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Solution Overview

Problem

The production of vertical components based on III-nitride compound semiconductors is challenging due to the lack of native nitride substrates, leading to the use of incompatible substrates like silicon, which compromises the quality of gallium nitride and increases production costs, while integration with lateral components is complex and inefficient, affecting reliability and size constraints.

Innovation Solution

A high-performance component is developed using a method that involves selective epitaxial overgrowth to form a lateral heterostructure on a partial area of a vertical transistor component, eliminating the need for wafer bonding and allowing monolithic integration of vertical and lateral components, thereby reducing parasitic effects and enabling smaller, more efficient devices with high current-carrying capacities and low layer resistances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If wafer bonding or hybrid integration processes are used to integrate vertical and lateral components, then component functionality is achieved, but production costs and device complexity increase significantly

Engineering Contradiction:
Improveintegration capabilityVSAvoidproduction process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges vertical and lateral component fabrication into a single monolithic structure by forming the lateral heterostructure directly on the vertical component surface during the same epitaxial growth process, eliminating the need for separate wafer bonding or hybrid integration steps

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The device is segmented into functional regions (vertical component region and lateral component region) within a single continuous epitaxial structure, allowing each region to be optimized independently while maintaining structural integration

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If wafer bonding is used to assemble vertical and lateral components, then component integration is achieved, but device size and weight increase

Engineering Contradiction:
Improvecomponent integrationVSAvoiddevice weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

Multiple components are merged into a single monolithic epitaxial structure grown on one substrate, eliminating the need for separate substrates and bonding layers that would increase device weight

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If silicon substrates are used for vertical components, then production cost is reduced and large-area fabrication is enabled, but gallium nitride quality deteriorates

Engineering Contradiction:
Improveproduction costVSAvoidgallium nitride quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The device structure is segmented such that high-quality III-nitride layers are grown only where needed (in the vertical component region and lateral heterostructure region), while the silicon substrate is used only as a cost-effective base that does not contact the sensitive GaN channels

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A buffer layer structure acts as an intermediary between the silicon substrate and the III-nitride layers, decoupling the substrate's mechanical advantages from its negative impact on GaN crystal quality

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If selective epitaxial overgrowth is used to form lateral heterostructure on vertical component, then monolithic integration is achieved and parasitic effects are reduced, but manufacturing process complexity increases

Engineering Contradiction:
Improveparasitic effect reductionVSAvoidepitaxial process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The epitaxial overgrowth is applied selectively only to specific regions of the vertical component surface where lateral heterostructure is needed, while other regions maintain their original structure, allowing localized optimization without affecting the entire device

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 results in high-efficiency, high-power-density components suitable for energy-efficient power electronics, electromobility, and photovoltaics, with improved reliability and reduced production costs by eliminating the need for wafer bonding and using the quality of III-nitride technology.

Implementation Method 1

the lateral heterostructure of the second component is formed monolithically on a partial region of a surface of the vertical component by means of selective epitaxial overgrowth

Methodology Applied
Scientific EffectEpitaxy: Epitaxy

Data Source

PatentEP4451322A1High-performance iii-nitride compound semiconductor device, intermediate product, and method for manufacturing high-performance device
Publication Date: 2024.10.23 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4451322A1 patent drawingFigure 1a~1c
  • EP4451322A1 patent drawingFigure 2~3
  • EP4451322A1 patent drawingFigure 4~5

AI summary

The invention relates to a high-performance device (1) based on III nitride compound semiconductors, comprising at least a first, vertical transistor device (2) and at least a second device (10) with a lateral heterostructure (11), wherein the lateral heterostructure (11) of the second device (10) is formed monolithically on a partial region (4) of a surface (3) of the first, vertical device (2) by selective epitaxial growth, wherein the second device (10) comprises at least one transistor and optionally further active and/or passive devices, and wherein both the first transistor device (2) and the second device (10) are formed based on III nitride compound semiconductors. The invention further relates to an intermediate product (16) for the production of a high-performance device (1) and a method for the production of a high-performance device (1) based on III nitride compound semiconductors.