Power Semiconductor Fin Spacer Layout to Prevent Electrode Shorts
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Solution Overview
Problem
Power semiconductor devices face reliability issues due to accidental electrical contacts between load terminals and gate electrodes, which can occur during production or over time, leading to reduced reliability and efficiency.
Innovation Solution
A method of producing a power semiconductor device involves creating a semiconductor body with a vertically protruding fin covered by insulation and electrode materials, forming recesses adjacent to the fin, and forming insulating sidewall spacers that terminate at a specific pull-back distance below the fin's top, ensuring electrical insulation and reducing the risk of accidental contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the electrode material is placed close to the fin for compact design, then device area is reduced, but the risk of accidental electrical contact between load terminals and gate electrodes increases
Solution Approach 1:
The patent introduces an insulating sidewall spacer as an intermediary element between the electrode material and the fin. This spacer creates a physical barrier that prevents accidental electrical contact while allowing the electrode to remain in close proximity to the fin for compact device design. The spacer acts as a mediator that maintains both reliability and area efficiency.
Solution Approach 2:
The patent solves the contradiction by transitioning from a two-dimensional planar separation to a three-dimensional vertical structure. The insulating sidewall spacer extends vertically along the fin, creating separation in the vertical dimension while maintaining horizontal compactness. This dimensional transition allows close electrode-fin placement without compromising reliability.
2Power
If the fin structure is made taller for better current conduction, then current carrying capacity is improved, but the complexity of maintaining proper insulation and contact increases
Solution Approach 1:
The patent applies preliminary action by forming the insulating sidewall spacer before creating the contact opening. This preliminary insulation structure is established in advance, simplifying subsequent processing steps. The spacer is formed conformally on the fin surface, ensuring proper insulation is in place before any contact structures are created, thereby reducing overall device complexity.
Solution Approach 2:
The patent applies local quality by providing insulation only where needed - specifically on the sidewalls of the fin where the electrode material is present. The insulating sidewall spacer is localized to the regions adjacent to the electrode, rather than covering the entire fin structure. This localized approach maintains current conduction efficiency while providing necessary insulation, reducing unnecessary complexity.
3Reliability
If the pull-back distance of sidewall spacers is increased for better insulation, then electrical insulation is improved, but the contact area between load terminal and fin is reduced
Solution Approach 1:
The patent applies partial action by providing insulation only in the specific regions where the electrode material is present, rather than uniformly across the entire fin structure. The insulating sidewall spacer is formed with a width that provides sufficient insulation distance from the electrode to the fin surface, but does not excessively reduce the contact area. This partial insulation approach maintains both reliability and adequate contact area.
Data Source
AI summary
A power semiconductor device includes: a semiconductor body with a vertically protruding fin configured to conduct a portion of a nominal load current of the device; and a first load terminal in contact with an upper portion of the fin. An electrode material is arranged adjacent to the fin and electrically insulated from the fin by insulation material. The electrode material is electrically insulated from the first load terminal by an insulating material. The power semiconductor device further includes, on top of the electrode material, insulating sidewall spacers adjacent to the insulating material and the insulation material. The sidewall spacers terminate at a pull-back distance below the top of the fin. The pull-back distance amounts to at least 90% of a width of the fin at the top of the fin.