GaN Semiconductor Protective Film Segmentation for Etching
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Solution Overview
Problem
GaN-based semiconductor devices face challenges in reducing leak current and improving workability of protective films, particularly with Al2O3 films, where increasing thickness for dielectric breakdown strength leads to etching failures during wet etching.
Innovation Solution
A semiconductor device structure comprising a first layer of aluminum oxide (Al2O3) to reduce leak current and a second layer of a different electrical insulation material, such as silicon dioxide (SiO2), to enhance dielectric breakdown strength, allowing for reduced thickness of the first layer and improved etching flexibility, including the option for wet or dry etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the protective film made of Al2O3 is increased to ensure sufficient dielectric breakdown strength, then the electrical properties are improved, but etching failure (peel-off or drop-off of resist mask) occurs during wet etching processing
Solution Approach 1:
The protective film is divided into two separate layers: a first layer made of Al2O3 that provides excellent interface passivation and leak current reduction, and a second layer made of a different electrical insulation material that provides sufficient dielectric breakdown strength and etching stopper function. This segmentation allows each layer to be optimized for its specific function without compromising the other.
Solution Approach 2:
The protective film uses a composite structure combining Al2O3 with another electrical insulation material. The Al2O3 layer provides superior interface quality and leak current characteristics, while the second layer material (such as SiO2, SiN, SiON, HfO2, AlN, ZrO2, or ZrON) provides adequate dielectric breakdown strength and serves as an etching stopper, creating a composite material system that achieves both electrical performance and manufacturing workability.
2Ease of manufacture
If the thickness of the protective film is reduced to improve etching workability, then etching failures are suppressed, but the dielectric breakdown strength becomes insufficient
Solution Approach 1:
The protective film is divided into two separate layers: a first layer made of Al2O3 that provides excellent interface passivation and leak current reduction, and a second layer made of a different electrical insulation material that provides sufficient dielectric breakdown strength and etching stopper function. This segmentation allows each layer to be optimized for its specific function without compromising the other.
Solution Approach 2:
The protective film uses a composite structure combining Al2O3 with another electrical insulation material. The Al2O3 layer provides superior interface quality and leak current characteristics, while the second layer material (such as SiO2, SiN, SiON, HfO2, AlN, ZrO2, or ZrON) provides adequate dielectric breakdown strength and serves as an etching stopper, creating a composite material system that achieves both electrical performance and manufacturing workability.
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 solution effectively reduces leak current, enhances dielectric breakdown strength, and improves the workability of the protective film, suppressing etching failures and potential damage to semiconductor layers while allowing for cost reduction, miniaturization, and easier manufacturing.
Implementation Method 1
a first layer made of aluminum oxide (Al2O3) and arranged adjacent to the p-type semiconductor layer and the n-type semiconductor layer to coat an edge of a p-n junction surface
Implementation Method 2
a second layer made of an electrical insulation material different from aluminum oxide (Al2O3) and formed on the first layer
Implementation Method 3
In terms of reducing the potential damage of the semiconductor layer, wet etching is more preferable than dry etching for the etching process of the protective film
Data Source
AI summary
A semiconductor device includes: a p-type semiconductor layer mainly made of GaN; an n-type semiconductor layer mainly made of GaN and joined with the p-type semiconductor layer; a protective film arranged to coat the p-type semiconductor layer and the n-type semiconductor layer; a gate insulating film arranged to coat the p-type semiconductor layer and the n-type semiconductor layer; and a gate electrode joined with the gate insulating film. The protective film includes: a first layer made of Al2O3 and arranged adjacent to the p-type semiconductor layer and the n-type semiconductor layer to coat an edge of a p-n junction surface; a second layer made of an electrical insulation material different from Al2O3 and formed on the first layer; and an opening structure formed to pass through the first layer and the second layer. The gate insulating film is placed inside of the opening structure.