Selective Gallium Oxide Dry Etching Without GaN Surface Damage
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Solution Overview
Problem
Conventional etching methods for gallium oxide, such as wet etching and plasma etching, result in surface defects and reduced selectivity relative to gallium nitride, leading to degraded quantum efficiency and performance in micro-LEDs due to the inability to delicately remove gallium oxide without damaging underlying gallium nitride surfaces.
Innovation Solution
A dry etching process using specific reagents like chloride and bromide in a plasma-free environment, which selectively etches gallium oxide relative to gallium nitride, minimizing surface damage and achieving high etching selectivity by forming volatile gallium-containing gases that are easily purged, thereby controlling the etch depth and preventing damage to gallium nitride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wet etching or plasma etching is used to remove gallium oxide, then the etching process can proceed, but surface defects are created and selectivity relative to gallium nitride is reduced
Solution Approach 1:
The patent changes the chemical parameters of the etching process by using organic halide reagents (such as methyl chloride, ethyl bromide) instead of conventional inorganic etchants. This parameter change enables selective removal of gallium oxide through formation of volatile gallium halide species, achieving both high etching rate and minimal surface damage to gallium nitride.
Solution Approach 2:
The patent employs an inert or reducing atmosphere (using organic halide reagents in the absence of oxygen or water) to prevent oxidation of the gallium nitride surface during etching. This inert environment protects the underlying gallium nitride from damage while allowing selective etching of gallium oxide through volatile gallium halide formation.
2Productivity
If conventional plasma etching is used, then etching can occur, but selectivity between gallium oxide and gallium nitride is reduced
Solution Approach 1:
The patent changes the chemical state parameters by using organic halide reagents that decompose to provide controlled halogen species. This enables selective reaction with gallium oxide to form volatile gallium halides, achieving greater than 10:1 selectivity over gallium nitride, whereas conventional plasma etching provides insufficient selectivity.
Solution Approach 2:
The patent replaces the physical/mechanical plasma etching mechanism with a chemical vapor deposition-style process using organic halide reagents. This substitution allows selective chemical reaction with gallium oxide through volatile product formation, whereas plasma etching relies on physical ion bombardment that lacks sufficient material selectivity.
3Productivity
If aggressive etching methods are used to remove gallium oxide quickly, then productivity increases, but damage to underlying gallium nitride surfaces occurs
Solution Approach 1:
The patent changes the chemical reactivity parameters by using organic halide reagents that selectively react with gallium oxide at controlled rates. The decomposition of these reagents provides gentle, controlled halogen species that etch gallium oxide through volatile gallium halide formation without the aggressive ion bombardment that damages gallium nitride surfaces.
Solution Approach 2:
The patent introduces organic halide reagents as intermediary substances that mediate the etching process. These reagents decompose to provide controlled halogen species that selectively react with gallium oxide, acting as a buffer that prevents direct aggressive contact with the gallium nitride surface while maintaining high etching productivity.
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 dry etching process effectively removes gallium oxide with high selectivity (>10:1) and minimal impact on gallium nitride, reducing surface defects and enhancing the quantum efficiency of micro-LEDs by maintaining a plasma-free environment and using specific reagents to control the etching process.
Implementation Method 1
contacting the exposed region of gallium oxide with the at least one of chloride and bromide from the reagent to form a gallium-containing gas
Implementation Method 2
purging the substrate processing region with an inert gas to remove the gallium-containing gas
Data Source
AI summary
Exemplary methods of etching gallium oxide from a semiconductor substrate may include flowing a first reagent in a substrate processing region housing the semiconductor substrate. The first reagent may include HX. X may be at least one of fluorine, chlorine, and bromine. The semiconductor substrate may include an exposed region of gallium oxide. Fluorinating the exposed region of gallium oxide may form a gallium halide and H2O. The methods may include flowing a second reagent in the substrate processing region. The second reagent may be at least one of trimethylgallium, tin acetylacetonate, tetramethylsilane, and trimethyltin chloride. The second reagent may promote a ligand exchange where a methyl group may be transferred to the gallium halide to form a volatile Me2GaY or Me3Ga. Y may be at least one of fluorine, chlorine, and bromine from the second reagent. The methods may include recessing a surface of the gallium oxide.