Capacitively Coupled Field Plate Semiconductor Termination
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Solution Overview
Problem
Conventional semiconductor devices face challenges in preventing moisture and contaminants from entering the active regions due to direct electrical contact between metal field plates and equipotential rings, which can degrade device integrity, especially in humid environments.
Innovation Solution
A termination region design that employs insulation layers, such as a field oxide layer, to capacitively couple field rings with metal field plates and polysilicon elements, preventing direct electrical contact and enhancing moisture sealing while managing electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal field plates and equipotential rings are directly electrically contacted with field rings, then electrical connectivity is ensured, but moisture and contaminants can ingress into the active regions degrading device integrity
Solution Approach 1:
An insulation layer is introduced as an intermediary between the metal field plate/equipotential ring and the field ring. This insulation layer prevents direct electrical contact while allowing capacitive coupling to maintain the electrical field management function. The insulation layer acts as a barrier that blocks moisture and contaminant ingress paths while preserving the necessary electrical functionality through capacitive interaction.
2Object-affected harmful factors
If insulation layers are introduced to prevent direct contact between field rings and metal components, then moisture sealing is enhanced, but direct electrical contact is lost
Solution Approach 1:
The patent replaces the mechanical/direct electrical contact system with a capacitive coupling system. Instead of relying on direct physical contact between metal components and field rings for electrical connectivity, the insulation layer enables capacitive coupling that achieves the same electrical field management function without requiring direct contact. This substitution eliminates the moisture ingress pathway while maintaining electrical functionality through the capacitive effect.
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 capacitive coupling effectively manages electric fields and prevents contamination ingress, ensuring the semiconductor device's integrity and performance in humid environments by isolating the field rings from metal components.
Implementation Method 1
an insulation layer disposed to prevent direct electrical contact between the field rings and the field plate such that the at least one field ring is capacitively coupled with the at least one field plate
Implementation Method 2
A field plate is typically comprised of a metal, such as aluminum, or other conductor materials, and extends the electric potential forces at the depletion layer to beyond the edge of the field plate, thus reducing the depletion layer curvature and the intensity of the electric field
Data Source
AI summary
A termination region of a semiconductor die is provided, which includes one or more field rings arranged in the termination region, one or more metal field plates, and an insulation layer disposed to prevent direct electrical contact between the field rings and the field plate such that the at least one field ring is capacitively coupled with the at least one field plate. Such a termination region may also include a polysilicon plate capacitively coupled with a diffusion region laterally spaced from the field rings, the polysilicon plate being located at an outer surface or directly under a passivation layer at an outer surface of the die. The termination region may also include floating field rings. The insulation layer may be a field oxide layer.