Electrodeless PEC Etching of Group III Nitride Wafers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a lack of effective techniques for performing electrodeless photoelectrochemical (PEC) etching of Group III nitride wafers, which requires complex setups like cathode electrodes and external circuits, limiting its application, especially for large-diameter wafers with high dislocation density.
Innovation Solution
A method involving a wafer immersed in an etching solution containing peroxodisulfate ions, where the surface is irradiated with specific wavelengths of light (200 nm to 310 nm and 310 nm to 365 nm) to generate radicals and holes for etching, eliminating the need for a cathode electrode and external circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional PEC etching with cathode electrode and external circuit is used, then etching can be performed, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The invention extracts and removes the cathode electrode and external circuit from the PEC etching system, retaining only the essential anode (wafer) and etching solution components. This simplification eliminates the complex wiring and electrode assembly while maintaining the core photoelectrochemical etching functionality through direct light irradiation of the wafer in the etching solution.
Solution Approach 2:
The wafer serves as its own anode in this electrodeless PEC etching method, eliminating the need for separate electrode structures. The system uses the wafer's inherent properties and the etching solution's chemical composition to achieve etching without requiring external power circuits or additional electrodes, making the process self-sufficient and simpler to operate.
2Manufacturing precision
If single wavelength light irradiation is used, then irradiation setup is simple, but etching uniformity and flatness deteriorate
Solution Approach 1:
The irradiation system is segmented into multiple independent light sources, each emitting at different wavelengths optimized for specific etching functions. This segmentation allows precise control over the photoelectrochemical reactions, with each wavelength contributing to different aspects of the etching process, thereby improving etching uniformity and flatness through targeted spectral control.
Solution Approach 2:
The invention changes the light irradiation parameter from a single wavelength to multiple wavelengths, optimizing the spectral distribution to match the absorption characteristics of the etching solution and wafer material. This parameter optimization enables better control over the etching rate and quality, achieving superior uniformity and flatness results.
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 allows for efficient and uniform etching of Group III nitride wafers without the need for additional electrodes or circuits, improving etching uniformity and flatness, and can be applied to large-diameter wafers with low dislocation density.
Implementation Method 1
irradiating the surface of the wafer with light through the etching solution; wherein the group III nitride crystal has a composition in which a wavelength corresponding to a band gap is 310 nm or more, and during irradiation of the light, the surface of the wafer is irradiated with a first light having a wavelength of 200 nm or more and less than 310 nm
Implementation Method 2
irradiated with a second light having a wavelength of 310 nm or more and less than a wavelength corresponding to a band gap under a second irradiation condition
Data Source
AI summary
There is provided a structure manufacturing method, including: preparing a wafer at least whose surface comprises Group III nitride crystal in a state of being immersed in an etching solution containing peroxodisulfate ions; and irradiating the surface of the wafer with light through the etching solution; wherein the group III nitride crystal has a composition in which a wavelength corresponding to a band gap is 310 nm or more, and during irradiation of the light, the surface of the wafer is irradiated with a first light having a wavelength of 200 nm or more and less than 310 nm under a first irradiation condition, and is irradiated with a second light having a wavelength of 310 nm or more and less than a wavelength corresponding to the band gap under a second irradiation condition controlled independently of the first irradiation condition.