GaN Etching via Ion Implantation and Oxidation
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Solution Overview
Problem
Current etching methods for III-N materials, such as GaN, face challenges in precision and productivity due to ion bombardment and lack of control over etching depth, leading to degradation of the AlGaN layer and reduced device performance.
Innovation Solution
A method involving hydrogen and/or helium ion implantation followed by oxygen plasma oxidation and selective etching allows for precise control of etching depth and reduced duration, using a plasma-based process that modifies the layer surface for improved homogeneity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional plasma etching with chlorinated chemistries is used, then the etching process can be performed, but the ion bombardment degrades the materials of the layers and patterns, leading to reduced device performance
Solution Approach 1:
The patent applies preliminary action by performing ion implantation (hydrogen and/or helium) before the etching process. This pre-modifies the GaN layer structure, creating regions that are more resistant to ion bombardment damage during subsequent etching, thereby protecting the material while maintaining etching efficiency
Solution Approach 2:
The patent changes the physical and chemical parameters of the GaN layer through ion implantation, altering the material properties in specific regions. This creates a modified structure that responds differently to plasma etching, reducing damage while maintaining controlled etching rates
2Device complexity
If traditional plasma etching is used, then the process is simple, but controlling the etching depth is not very precise due to the absence of a stop layer
Solution Approach 1:
The patent implements a feedback mechanism through cyclic etching processes. By repeating alternating etching and oxidation steps, the process provides self-regulation where the oxidation step creates a protective layer that prevents over-etching, enabling precise depth control without adding significant complexity
Solution Approach 2:
The patent employs periodic action through cyclic etching processes that alternate between etching steps and oxidation steps. This periodic repetition allows for controlled removal of material at precise depths, with each cycle removing a controlled amount of material while the oxidation provides a self-limiting mechanism
3Manufacturing precision
If cyclic etching techniques are used to limit disadvantages, then the control of etched thickness is improved and surface damage is reduced, but the implementation duration is significant and not compatible with industrial requirements
Solution Approach 1:
The patent optimizes process parameters including ion implantation energy, dose, and plasma conditions to achieve faster etching rates while maintaining precision. By carefully controlling these parameters, the process reduces the number of cycles needed while preserving the benefits of cyclic etching
Solution Approach 2:
The patent applies preliminary ion implantation to enhance the etching rate in subsequent steps. This pre-modification of the material structure allows for faster removal of material in the etching phase, reducing overall process time while maintaining the precision benefits of cyclic processing
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 enables precise and efficient etching of III-N layers with reduced damage and increased productivity, resulting in improved device performance and compatibility with industrial requirements.
Implementation Method 1
modifying, by implanting hydrogen (H)- and/or helium (He)-based ions, at least some of the thickness (e100) of said layer to form in said layer at least one modified portion
Implementation Method 2
oxidising at least some of the modified portion by exposing said layer to an oxygen-based plasma, to define in said at least one oxidised portion and at least one non-oxidised portion
Implementation Method 3
etching the at least one oxidised portion selectively at the at least one non-oxidised portion
Data Source
AI summary
A method for etching at least one layer of a gallium nitride (GaN)-based material is provided, the method including: providing the GaN-based layer having a front face; and at least one cycle including the following successive steps: modifying, by implanting hydrogen (H)- and/or helium (He)-based ions, at least some of a thickness of the GaN-based layer to form in the layer at least one modified portion extending from the front face, the implanting being carried out from a plasma, the modifying by implanting being carried out such that the modified portion extends from the front face and over a depth greater than 3 nm; oxidizing at least some of the modified portion by exposing the layer to an oxygen-based plasma, to define in the layer, at least one oxidized portion and at least one non-oxidized portion; and etching the oxidized portion selectively at the non-oxidized portion.