GaN Epitaxial Peeling Structure for Lower Dislocation Density
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Solution Overview
Problem
Current methods for growing GaN-based materials using MOCVD technology result in high dislocation densities, which hinder the development of high-voltage GaN-based power devices and long-wavelength LEDs, necessitating a new manufacturing method to reduce dislocation density effectively.
Innovation Solution
A semiconductor structure manufacturing method involving a structure to be peeled off, comprising a base with a first mask layer and a first epitaxial layer, where the first opening in the mask layer exposes the base, and a second epitaxial layer is grown on top, allowing for peeling by applying force perpendicular to the base, exploiting thermal expansion differences and epitaxial growth techniques to reduce dislocation density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOCVD technology is used to grow GaN-based materials, then the manufacturing process is mature and efficient, but the dislocation density becomes high which hinders device performance
Solution Approach 1:
The patent divides the continuous epitaxial layer into discrete columnar structures by growing material through patterned openings in a mask layer. This segmentation approach allows each column to be grown independently, preventing dislocation propagation between columns while maintaining high manufacturing efficiency through parallel growth processes.
Solution Approach 2:
The patent applies different structural configurations to different regions: the mask layer with patterned openings creates localized growth zones, while the spaces between openings allow dislocations to terminate. This local quality differentiation enables high-density growth in controlled regions while maintaining low dislocation density overall.
2Manufacturing precision
If a mask layer with openings is used to grow epitaxial layers, then dislocation density is reduced, but the process complexity increases
Solution Approach 1:
The patent introduces a mask layer as an intermediary component that simplifies the overall process. The mask layer with patterned openings serves as a template that guides epitaxial growth, automatically creating the desired columnar structure without requiring complex post-processing or multiple growth steps. This intermediary layer reduces process complexity despite adding a fabrication step.
Solution Approach 2:
The mask layer is prepared in advance with the desired pattern of openings before epitaxial growth begins. This preliminary action defines the growth zones and dislocation termination regions upfront, eliminating the need for complex real-time control during the growth process and simplifying the overall manufacturing sequence.
3Manufacturing precision
If force is applied to peel off the first structure, then the second structure forms a thin semiconductor structure with reduced defects, but the mechanical stress may cause additional damage
Solution Approach 1:
The patent extracts the first structure (containing the mask layer and initial epitaxial layers) from the second structure (containing the final GaN layers) by applying peeling force. This extraction separates the defect-containing sacrificial structure from the high-quality semiconductor structure, allowing the latter to be obtained with reduced defects while the former is discarded or reused.
Solution Approach 2:
The patent designs the first epitaxial layer with specific material properties and thickness to serve as a cushioning layer that absorbs mechanical stress during the peeling process. This beforehand cushioning prevents stress from propagating to the second structure, protecting it from damage while enabling clean separation of the first structure.
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 method effectively reduces dislocation density in GaN-based materials, enabling the production of high-voltage power devices and long-wavelength LEDs with improved performance by terminating dislocation extension and facilitating low-cost peeling to form a thin semiconductor structure with reduced defects.
Implementation Method 1
a first epitaxial layer epitaxially grown from the base to fill up the first opening
Implementation Method 2
a thermal expansion coefficient of the second epitaxial layer is greater than a thermal expansion coefficient of the first mask layer
Data Source
AI summary
The present disclosure provides a manufacturing method of semiconductor structure, including: providing a structure to be peeled off, where the structure to be peeled off includes a first structure and a second structure, the first structure includes: a base; a first mask layer located on the base, where a first opening that exposes the base is provided in the first mask layer, and a first epitaxial layer epitaxially grown from the base to fill up the first opening; and the second structure includes: a second epitaxial layer located on the first epitaxial layer and the first mask layer; and applying force on the structure to be peeled off to fracture the second epitaxial layer and the first epitaxial layer, to peel off the first structure and make the second structure form a semiconductor structure.