GaN Semiconductor P-type Guard Ring Epitaxial Growth
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Solution Overview
Problem
Conventional methods for manufacturing gallium nitride (GaN) based semiconductor devices, such as Schottky diodes, face challenges in creating reliable and high-quality P-type guard rings due to the wide band-gap nature of nitride semiconductors, which results in highly resistive or semi-insulative edge termination structures with defects, leading to poor reliability and unclamped inductive switching (UIS) capability.
Innovation Solution
The formation of P-type guard rings near the edges of GaN-based semiconductor devices using an epitaxial growth process in trenches, allowing for controllable dopant profiles, reduced resistance, and improved structural integrity, thereby enhancing the reliability and performance of the termination structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional implant and diffusion processes are used to form guard rings in GaN devices, then the manufacturing process is simple and familiar, but the resulting guard rings are highly resistive or semi-insulative with defects, leading to poor reliability
Solution Approach 1:
The patent changes the fundamental manufacturing parameter from post-growth implant/diffusion processes to in-situ epitaxial growth with doping. This allows P-type dopants to be incorporated during the GaN layer formation itself, creating true P-type semiconductor regions with proper electrical characteristics rather than highly resistive or semi-insulative structures, thereby improving guard ring reliability
Solution Approach 2:
The patent replaces the mechanical implantation process with a chemical epitaxial growth process. Instead of physically implanting dopants into the GaN lattice and relying on thermal diffusion, the dopants are incorporated chemically during the epitaxial growth of the GaN layer, resulting in better dopant distribution and lower resistance guard rings
2Reliability
If ion implantation is used to form guard rings, then the process can be implemented with existing equipment, but the guard rings become highly resistive and contain defects from the implant process, reducing UIS capability
Solution Approach 1:
The patent performs dopant incorporation during the epitaxial growth process itself, before any subsequent processing steps. By incorporating P-type dopants in-situ during GaN layer formation, the guard rings are created with proper doping profiles and crystal structure integrity from the beginning, avoiding the damage and defects that would result from later ion implantation and thermal processing
Solution Approach 2:
The patent changes the doping mechanism from post-growth ion implantation to in-situ epitaxial doping. This fundamental parameter change allows for precise control of dopant concentration and distribution during the growth process, creating high-quality P-type regions with uniform doping and no implantation-induced defects, thereby improving UIS capability
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 epitaxial growth method results in high-quality, reliable P-type guard rings that effectively reduce high electric fields and leakage current, improving the breakdown performance and UIS capability of GaN-based semiconductor devices.
Implementation Method 1
growing a doped gallium nitride based epitaxial layer in the trench to function as guard ring
Data Source
AI summary
This invention discloses a gallium nitride based semiconductor power device disposed in a semiconductor substrate. The power device comprises a termination area disposed at a peripheral area of the semiconductor power device comprises a termination structure having at least a guard ring disposed in a trench filled with doped gallium-based epitaxial layer therein.