GaN PEC Etching for High Aspect Ratio Recesses
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Solution Overview
Problem
The processing of gallium nitride (GaN) materials using photo-electrochemical (PEC) etching is not well understood, and existing methods often result in damaged surfaces and poor flatness of etched features, limiting the formation of high-quality recesses and protrusions with desired aspect ratios.
Innovation Solution
A method involving PEC etching of GaN materials with controlled etching voltage, typically around 1 V, to achieve superior internal flatness and aspect ratios, using a low dislocation density and high in-plane uniformity GaN substrates, and employing specific etching conditions to minimize side etching and maintain the smoothness of side faces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PEC etching is used to etch GaN materials, then less damage is caused compared to dry etching, but the understanding of processing methods is insufficient and results in poor flatness
Solution Approach 1:
The patent applies parameter changes by optimizing the PEC etching voltage to a specific range (0.5-2.0 V) to achieve the desired balance between minimizing material damage and achieving high flatness. By carefully controlling the voltage parameter, the etching process produces recesses with aspect ratios of 5 or more while maintaining superior internal flatness and reducing dislocation density, thus resolving the contradiction between reduced damage and improved manufacturing precision.
2Shape
If high aspect ratio recesses are formed, then the structure complexity increases, but the internal flatness and crystal quality are maintained
Solution Approach 1:
The patent replaces conventional mechanical or chemical etching methods with PEC etching, which uses electrochemical reactions to achieve the desired high aspect ratio structures. This substitution enables the formation of recesses with aspect ratios of 5 or more while maintaining simple process conditions and superior internal flatness, effectively managing structure complexity through a more controlled electrochemical approach.
3Manufacturing precision
If side etching is minimized, then the precision of recess dimensions is improved, but the etching process requires more precise control
Solution Approach 1:
The patent achieves precise dimensional control by optimizing the PEC etching voltage to a specific range (0.5-2.0 V). This parameter optimization minimizes side etching and enables the formation of recesses with aspect ratios of 5 or more while maintaining simple process conditions. The controlled voltage range ensures high dimensional precision without requiring overly complex process control systems.
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 method enables the formation of GaN structures with high aspect ratios, such as recesses and protrusions, with superior internal flatness and minimal damage to the crystal, maintaining band-edge peak intensities and reducing profile roughness, thus improving the quality of GaN materials for semiconductor devices.
Implementation Method 1
Etching that involves anodic oxidation (also referred to as 'photo-electrochemical (PEC) etching' below) is being proposed as a technique to etch GaN materials
Implementation Method 2
Etching that involves anodic oxidation (also referred to as 'photo-electrochemical (PEC) etching' below)
Data Source
AI summary
This invention provides a novel structure formed from GaN material using PEC etching. The structure comprises a member constituted by a single crystal of gallium nitride and the member includes a recess having an aspect ratio of 5 or more.