3D GaN HEMT Epitaxy Wafer for Heat Dissipation and Crystal Quality
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Solution Overview
Problem
Conventional GaN HEMT devices suffer from deteriorated heat dissipation characteristics and crystal quality due to thickness increase and impurity doping, which affects device reliability and lifespan.
Innovation Solution
A high-quality GaN HEMT power semiconductor epitaxy wafer with a three-dimensional nitride structure is developed, featuring a varying composition ratio along the lateral direction, formed on a SiC or Si growth substrate, and comprising a nucleation region of AlN and a three-dimensional AlInGaN structure, which alleviates lattice constant differences and annihilates dislocations, enabling an ultra-thin epitaxy structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of GaN HEMT device is increased, then the film formation quality is improved, but the heat dissipation characteristics deteriorate
Solution Approach 1:
The patent introduces a three-dimensional nitride structure (nanopillars, nanowires, or nanotubes) with vertical orientation perpendicular to the substrate surface. This 3D architecture enables heat to dissipate through multiple pathways (radially outward and vertically upward) rather than being constrained to planar diffusion, significantly improving heat dissipation efficiency while maintaining a compact footprint that preserves film quality.
Solution Approach 2:
The three-dimensional nitride structure creates a porous or hierarchical architecture within the GaN HEMT device. This porous structure increases the surface area-to-volume ratio, providing enhanced thermal conduction pathways and facilitating more efficient heat removal from the active regions without compromising the integrity and quality of the thin film layers.
2Reliability
If impurity doping is used in GaN buffer region, then high-resistance layer is formed to reduce vertical leakage current, but film formation quality deteriorates
Solution Approach 1:
The patent extracts or removes the impurity doping step from the GaN buffer region fabrication process. Instead of introducing iron or carbon dopants to create high-resistance layers, the invention achieves leakage current reduction through alternative means such as optimized buffer layer composition, graded structures, or the three-dimensional nitride architecture that provides natural electrical isolation, thereby maintaining superior film formation quality.
Solution Approach 2:
The three-dimensional nitride structure serves as an intermediary element that provides both electrical isolation (reducing vertical leakage current) and structural support. This intermediary structure achieves the high-resistance function without requiring impurity doping, thus preventing the deterioration of film formation quality while still providing the necessary electrical isolation.
3Temperature
If the thickness of GaN HEMT device is minimized for heat dissipation, then heat dissipation characteristics improve, but crystal quality deteriorates
Solution Approach 1:
By transitioning from a planar 2D structure to a 3D vertical structure, the patent enables thin film devices to achieve excellent heat dissipation through the third dimension (vertical height and radial surfaces). The three-dimensional nitride pillars or wires provide efficient thermal pathways that do not depend on increasing lateral thickness, allowing minimal device thickness while maintaining high crystal quality.
Solution Approach 2:
The patent employs a composite structure combining the three-dimensional nitride phase (AlN, GaN, or InGaN) with the surrounding GaN HEMT layers. This composite architecture leverages the superior thermal conductivity and structural stability of the nitride phase to maintain crystal quality in the thin-film regime while achieving enhanced heat dissipation performance.
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 three-dimensional nitride structure improves crystal quality, minimizes heat generation, and enhances heat dissipation, resulting in improved device reliability and lifespan.
Implementation Method 1
having a composition ratio that varies along a lateral direction... alleviates lattice constant differences
Implementation Method 2
annihilates dislocations
Implementation Method 3
GaN HEMT epitaxy wafers... are manufactured by depositing a film on an electrically insulating silicon carbide (SiC) or silicon (Si) substrate
Data Source
AI summary
Embodiments according to the present invention provide a high-quality GaN HEMT power semiconductor epitaxy wafer having a three-dimensional nitride structure, comprising: a growth substrate; a nucleation region formed on the growth substrate; and a three-dimensional nitride structure region formed on the nucleation region and having a composition ratio that varies along a lateral direction.