Nitride Semiconductor Regrowth Layout to Prevent Surface Damage
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Solution Overview
Problem
Conventional semiconductor devices using nitride semiconductors face surface damage during manufacturing processes, particularly in regrown nitride semiconductor layers.
Innovation Solution
A method involving the formation of insulating layers to protect the surface of regrown nitride semiconductor layers, with electrodes and gate electrodes positioned to minimize interference from these layers, reducing surface damage and maintaining gate controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a regrown nitride semiconductor layer with high impurity concentration is formed to reduce on resistance, then the electrical conductivity is improved, but the surface of the regrown layer becomes damaged during manufacturing processes
Solution Approach 1:
A protective insulating film is introduced as an intermediary layer between the regrown nitride semiconductor layer and the etching environment. This insulating film prevents direct contact between the etchant and the semiconductor surface, thereby protecting the surface from damage while allowing the high impurity concentration structure to maintain its electrical conductivity benefits
Solution Approach 2:
The insulating film is formed on the regrown nitride semiconductor layer before the etching process. This preliminary protective action ensures that when subsequent etching or manufacturing steps are performed, the semiconductor surface is already protected, preventing damage before it can occur
2Manufacturing precision
If a mask is used to form openings in the insulating layer, then precise patterning is achieved, but the mask removal process damages the regrown nitride semiconductor layer surface
Solution Approach 1:
The insulating film serves as a protective intermediary that remains on the regrown nitride semiconductor layer during mask formation and removal. This allows precise patterning to be achieved using the mask, while the insulating film prevents the mask removal chemicals from damaging the semiconductor surface
Solution Approach 2:
The protective function is segmented from the structural function. The insulating film is divided into regions: some areas are removed to form openings for electrodes, while other areas remain to protect the semiconductor surface during mask removal, achieving both precise patterning and surface protection
3Object-affected harmful factors
If a second insulating layer is formed to cover the boundary line, then surface protection is improved, but the device structure becomes more complex
Solution Approach 1:
The second insulating layer is designed to perform multiple functions simultaneously: it covers the boundary line between different regions, provides continuous surface protection during subsequent processing steps, and maintains electrical isolation. This multi-functionality justifies the additional structural complexity by delivering multiple benefits from a single layer
Data Source
AI summary
A method for manufacturing a semiconductor device includes forming a first insulating layer on a first nitride semiconductor layer having a principal surface, forming a mask including a first mask opening on the first insulating layer, forming a first opening in the first insulating layer through the first mask opening, forming a second nitride semiconductor layer on the first nitride semiconductor layer inside the first opening, forming a second insulating layer covering a boundary between the second nitride semiconductor layer and the first insulating layer through the first mask opening and thereafter removing the mask, forming a second opening in the second insulating layer, forming a first electrode on the second insulating layer contacting the second nitride semiconductor layer through the second opening, and forming a gate electrode above the first nitride semiconductor layer, and separated from the second insulating layer in a plan view perpendicular to the principal surface.