Emitter Electrode Convex Layout for Trench Gate Oxide Reliability
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Solution Overview
Problem
In semiconductor devices with a vertical trench gate structure, high voltage drops near the resistance element for the gate pad can cause dielectric breakdown in the silicon oxide film, leading to reduced reliability due to impact ionization and residual carriers in the semiconductor substrate.
Innovation Solution
A semiconductor device design featuring a convex portion on the emitter electrode electrically connected to a well region via holes in the interlayer insulating film, which overlaps the resistance elements and gate wiring, effectively reducing the potential at the measurement point and preventing dielectric breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistance element is connected to the gate pad for protection circuit, then the semiconductor device is protected from surge voltage, but high voltage drop occurs near the resistance element causing dielectric breakdown in the silicon oxide film
Solution Approach 1:
A convex portion is added to the emitter electrode structure, positioned between the resistance element and the gate pad. This convex portion acts as an intermediary conductive structure that provides an alternative current path, reducing the voltage drop concentration near the resistance element and preventing dielectric breakdown in the silicon oxide film while maintaining the protection function.
Solution Approach 2:
The emitter electrode is modified by adding a convex portion that protrudes in the vertical dimension (thickness direction of the semiconductor substrate). This dimensional change creates a new spatial configuration that reduces electrical stress concentration in the horizontal plane near the resistance element, thereby preventing dielectric breakdown while maintaining surge protection functionality.
2Reliability
If the convex portion is added to the emitter electrode to reduce voltage drop, then dielectric breakdown is prevented, but the device structure becomes more complex
Solution Approach 1:
The convex portion is integrated into the existing emitter electrode structure rather than being a separate component. By merging the voltage reduction function into the emitter electrode itself, the design achieves the desired electrical performance while minimizing structural complexity and avoiding additional discrete elements.
Solution Approach 2:
The convex portion serves multiple functions: it reduces voltage drop near the resistance element, prevents dielectric breakdown in the silicon oxide film, and maintains the protection circuit functionality. This multi-functionality achieves reliability improvement without proportionally increasing device 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 enhances the reliability of the semiconductor device by reducing the likelihood of dielectric breakdown in the insulating film under the resistance element, improving switching characteristics and preventing voltage-induced damage.
Implementation Method 1
the convex portion and the well region are electrically connected via a hole formed in the interlayer insulating film
Implementation Method 2
a resistance element is connected to the gate pad as part of a protection circuit for protecting the semiconductor device from a surge voltage
Implementation Method 3
when a collector potential is further raised, an inside of the semiconductor substrate becomes a high electric field and the impact ions are generated
Data Source
AI summary
Two resistance elements are each formed so as to overlap a portion of each of a gate pad and a gate wiring in a plan view, and are electrically connected to the gate pad and the gate wiring. A p-type well region is formed so as to overlap a portion of each of the two insulating films, the two resistance elements, the gate pad, the gate wiring, and the emitter electrode in the plan view. The emitter electrode includes a convex portion that protrudes toward a gate pad side in a Y direction in the plan view. The convex portion is located between the two resistance elements in the plan view. The convex portion and the well region are electrically connected via a hole formed in an interlayer insulating film.