Semiconductor Edge Termination Taper Angle Control
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Solution Overview
Problem
Conventional semiconductor devices face challenges in maintaining withstand voltage due to electric field concentration near the edge termination portion, which can lead to avalanche breakdown, especially when the taper angle of the insulating film is larger than 60 degrees.
Innovation Solution
A semiconductor device design featuring a semiconductor substrate with an edge termination portion and an active portion, where the insulating film has a taper angle of 60 degrees or less, and a resistive film electrically connected to both the outer edge region and the well region, effectively reducing electric field intensity and preventing avalanche breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the taper angle of the insulating film is increased to simplify manufacturing, then the ease of manufacture is improved, but electric field concentration occurs leading to avalanche breakdown and reduced reliability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the taper angle of the insulating film to 60 degrees or less. This parameter optimization reduces electric field concentration at the edge termination portion while maintaining manufacturability, thereby preventing avalanche breakdown and ensuring reliable device operation at high withstand voltages
2Reliability
If the taper angle of the insulating film is decreased to prevent electric field concentration, then the withstand voltage is improved, but the manufacturing precision requirements become more stringent
Solution Approach 1:
The patent establishes a specific parameter range for the taper angle (60 degrees or less) that balances reliability improvement with manufacturing feasibility. This parameter specification ensures sufficient reduction of electric field concentration while remaining within achievable manufacturing tolerances
3Reliability
If a resistive film is added to reduce electric field intensity, then the withstand voltage is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a resistive film as an intermediary element between the metal electrode and the semiconductor substrate. This resistive film serves as a mediator that reduces electric field intensity at the edge termination portion through its resistive properties, thereby preventing avalanche breakdown and improving withstand voltage despite the added structural complexity
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 design effectively reduces the decrease in withstand voltage by controlling the taper angle of the insulating film, maintaining a higher rated withstand voltage when the taper angle is 48 degrees or less, thus preventing avalanche breakdown and ensuring reliable semiconductor device operation.
Implementation Method 1
a potential gradient is formed, depending on a potential difference between the base region and the stopper region. Electric fields may be formed in the resistive film, depending on the potential gradient. Any variation in the potential gradient is desirably adjusted to prevent an avalanche from occurring, due to the electric fields of the resistive film, in a semiconductor substrate located beneath the resistive film.
Implementation Method 2
In a resistive film electrically connecting a base region and a stopper region to each other, a potential gradient is formed, depending on a potential difference between the base region and the stopper region. Electric fields may be formed in the resistive film, depending on the potential gradient.
Data Source
AI summary
A semiconductor device including a semiconductor substrate having an edge termination portion and an active portion is provided. The edge termination portion includes an outer edge region provided on an end portion of a front surface of the semiconductor substrate and within a predetermined depth range. The active portion includes a well region provided on an inner side relative to the outer edge region of the front surface of the semiconductor substrate and within a predetermined depth range. The semiconductor device further includes an insulating film provided on the front surface of the semiconductor substrate and at least between the outer edge region and the well region and having a taper portion, and a resistive film provided on the insulating film and electrically connected to the outer edge region and the well region. A taper angle of the taper portion of the insulating film is 60 degrees or less.