Nitride Semiconductor ELO Structure for Flat Low-Defect Lateral Growth
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Solution Overview
Problem
The flatness of nitride semiconductor layers formed using Epitaxial Lateral Overgrowth (ELO) methods is compromised due to contact with mask portions, leading to increased defect density.
Innovation Solution
A semiconductor substrate design featuring a template substrate with a growth suppression region and a first seed region, including a first raised portion extending from the seed region, a growth suppression film, a first base portion, and a first wing portion separated from the growth suppression region, which allows for low defect density and high flatness by lateral growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the nitride semiconductor layer grows in the lateral direction and contacts the mask portion, then the growth area is increased, but the flatness of the layer decreases
Solution Approach 1:
The patent introduces a growth suppression film as an intermediary layer between the nitride semiconductor layer and the mask portion. This film prevents direct contact and harmful interaction while allowing the semiconductor layer to grow laterally. The growth suppression film acts as a mediator that enables extended growth area without compromising layer flatness, as it provides a controlled interface that suppresses unwanted epitaxial growth on the mask surface.
Solution Approach 2:
The patent segments the growth interface by introducing a distinct growth suppression film layer that separates the functional regions. The mask portion, growth suppression film, and nitride semiconductor layer are segmented into distinct functional zones, allowing independent optimization of each layer's properties and interactions, thereby maintaining flatness while enabling lateral expansion.
2Length of moving object
If the nitride semiconductor layer contacts the mask portion, then the lateral growth is enhanced, but the defect density increases
Solution Approach 1:
The growth suppression film serves as a protective intermediary that prevents direct contact between the nitride semiconductor layer and the mask portion. This intermediary layer allows lateral growth to proceed while blocking the transmission of defects and dislocations from the mask interface, thereby enhancing lateral dimension without increasing defect density.
Solution Approach 2:
The patent converts the potentially harmful direct contact interface into a beneficial separated structure by introducing the growth suppression film. The film transforms the harmful defect-generating contact into a beneficial controlled interface that enables lateral growth while suppressing defect formation, effectively turning the interface problem into a solution.
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 achieves a nitride semiconductor layer with reduced threading dislocations and improved flatness by utilizing a growth suppression film to prevent contact between the wing portion and the mask portion, enabling wider and defect-free growth.
Implementation Method 1
when a GaN layer is formed by film formation on a heterogeneous substrate, threading dislocations are generated from an interface between different materials
Data Source
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AI summary
Provided are a template substrate including a growth suppression region and a first seed region aligned in a first direction, and a first semiconductor part located above the template substrate and including a nitride semiconductor. The first semiconductor part includes a first raised portion extending from the first seed region to a location above the growth suppression region, a growth suppression film in contact with the first raised portion, a first base portion located above the first raised portion, and a first wing portion connected to the first base portion, separated from the growth suppression region, and located above a void space.