Basic Structure of GaN-based LED Epitaxial Layers
01 Introduction
The epitaxial layer structure of gallium nitride (GaN)-based LEDs is the core determinant of device performance, requiring careful consideration of material quality, carrier injection efficiency, luminescent efficiency, and thermal management. With evolving market demands for higher efficiency, yield, and throughput, epitaxial technology continues to advance. While mainstream manufacturers adopt similar foundational structures, key differentiators lie in nuanced optimizations that reflect R&D capabilities. Below is an overview of the most common GaN LED epitaxial structure.
02 Epitaxial Structure Overview
Sequentially grown on the substrate, the epitaxial layers typically include:
1. Buffer layer
2. Undoped GaN layer(Optional n-type AlGaN layer)
3. N-type GaN layer
4. Lightly doped n-type GaN layer
5. Strain-relief layer
6. Multiple quantum well (MQW) layer
7. AlGaN electron blocking layer (EBL)
8. Low-temperature p-type GaN layer
9. High-temperature p-type GaN layer
10.Surface contact layer
Common GaN LED Epitaxial Structures
Detailed Layer Functions
1）Buffer Layer
Grown at 500–800°C using binary (GaN/AlN) or ternary (AlGaN) materials.
Purpose: Mitigates lattice mismatch between substrate (e.g., sapphire) and epilayers to reduce defects.
Industry trend: Most manufacturers now pre-deposit AlN via PVD sputtering before MOCVD growth to enhance throughput.
2）Undoped GaN Layer
Two-stage growth: Initial 3D GaN islands followed by high-temperature 2D GaN planarization.
Outcome: Provides atomically smooth surfaces for subsequent layers.
3）N-type GaN Layer
Si-doped (8×10¹⁸–2×10¹⁹ cm⁻³) for electron supply.
Advanced option: Some designs insert an n-AlGaN interlayer to filter threading dislocations.
4）Lightly Doped n-GaN Layer
Lower doping (1×10¹⁸–2×10¹⁸ cm⁻³) creates a current-spreading high-resistance region.
Benefits: Improves voltage characteristics and luminescence uniformity.
5）Strain-Relief Layer
InGaN-based transition layer with graded In composition (between GaN and MQW levels).
Design variants: Superlattices or shallow-well structures to gradually accommodate lattice strain.
6）MQW (Multiple Quantum Well)
InGaN/GaN periodic stacks (e.g., 5–15 pairs) for radiative recombination.
Optimization: Si-doped GaN barriers reduce operating voltage and enhance brightness.
latest company news about Basic Structure of GaN-based LED Epitaxial Layers 2
7）AlGaN Electron Blocking Layer (EBL)
High-bandgap barrier to confine electrons within MQWs, boosting recombination efficiency.
8）Low-Temp p-GaN Layer
Mg-doped layer grown slightly above MQW temperature to:
Enhance hole injection
Protect MQWs from subsequent high-temperature damage
9）High-Temp p-GaN Layer
Grown at ~950°C to:
Supply holes
Planarize V-pits propagating from MQWs
Reduce leakage currents
10）Surface Contact Layer
Heavily Mg-doped GaN for ohmic contact formation with metal electrodes, minimizing operating voltage.
03 Conclusion
The GaN LED epitaxial structure exemplifies the synergy between materials science and device physics, where each layer critically impacts electro-optical performance. Future advancements will focus on defect engineering, polarization management, and novel doping techniques to push efficiency boundaries and enable emerging applications.
As a pioneer in gallium nitride (GaN) LED epitaxial technology, ZMSH has pioneered advanced GaN-on-sapphire and GaN-on-SiC epitaxial solutions, leveraging proprietary MOCVD (Metal-Organic Chemical Vapor Deposition) systems and precision thermal management to deliver high-performance LED wafers with defect densities below 10⁶ cm⁻² and uniform thickness control within ±1.5%. Our customizable substrates—including GaN-on-sapphire, blue sapphire, silicon carbide, and metal composite substrates—enable tailored solutions for ultra-high-brightness LEDs, micro-LED displays, automotive lighting, and UV-C applications. By integrating AI-driven process optimization and ultrafast pulsed laser annealing, we achieve <3% wavelength shift and >95% reliability, supported by automotive-grade certifications (AEC-Q101) and mass production scalability for 5G backlights, AR/VR optics, and industrial IoT devices.
The following is GaN substrate & Sapphire wafer of ZMSH:
* Please contact us for any copyright concerns, and we will promptly address them.
