Vertical Leakage Path in GaN Periphery for Lateral Leakage Prevention
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Solution Overview
Problem
III-V semiconductor dies, particularly GaN-based, face lateral leakage issues due to humidity and chemical reactions at the periphery, leading to device degradation and delamination, especially during the singulation process where mechanical damage and improper layer design create conductive pathways.
Innovation Solution
An intentional vertical leakage path is created in the periphery of the semiconductor die using an uninsulated connection structure that extends vertically, providing a low-resistance path to ground, thereby shorting lateral leakage paths and preventing voltage differences at the die edge, thus minimizing chemical reactions and degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the GaN die periphery is left open during singulation, then the manufacturing process is simple, but lateral leakage paths form due to potential differences at the open GaN surface
Solution Approach 1:
The patent introduces a vertical dimension solution by forming a conductive plug that extends vertically through the dielectric layer to connect the GaN periphery to a reference potential layer. This vertical conduction path counteracts the lateral potential differences that cause leakage, effectively solving the problem by adding a dimensional approach rather than modifying the lateral structure.
Solution Approach 2:
The conductive plug acts as an intermediary element between the GaN periphery and the reference potential layer. It mediates the potential difference by providing a controlled electrical connection that eliminates unwanted lateral leakage paths without requiring direct modification of the GaN material or complex additional structures.
2Strength
If a seal ring is added to protect the die sidewall during singulation, then mechanical damage is reduced, but the device complexity increases
Solution Approach 1:
The conductive plug structure serves multiple functions: it provides mechanical support to the die periphery during singulation (replacing the seal ring's protective function) and simultaneously establishes electrical connection to eliminate lateral leakage. This multi-functionality eliminates the need for separate seal ring structures, reducing overall device complexity.
Solution Approach 2:
The patent merges the mechanical protection function and electrical connection function into a single integrated structure. The conductive plug both reinforces the die periphery during handling and provides the necessary electrical path to reference potential, combining what would traditionally require separate components into one element.
3Object-affected harmful factors
If the passivation layer is continuous, then the GaN surface is protected from humidity, but manufacturing precision is reduced due to interruption requirements at sawing locations
Solution Approach 1:
The conductive plug acts as an intermediary that allows the passivation layer to be interrupted at sawing locations without compromising overall protection. By providing an alternative vertical electrical path through the plug, the system maintains electrical integrity even when the passivation is discontinuous, enabling manufacturing flexibility.
Solution Approach 2:
The patent accepts segmented passivation layers at sawing locations and compensates by introducing vertical conductive paths through the conductive plugs. This segmentation approach allows the passivation to be applied in sections during manufacturing while the plugs ensure continuous electrical protection across the entire die periphery.
4Power
If high electric fields are applied to achieve desired device performance, then device performance is improved, but electrochemical degradation accelerates in humid environments
Solution Approach 1:
The conductive plug establishes a reference potential connection at the GaN periphery before the device operates in humid conditions. This preliminary electrical stabilization prevents the formation of lateral potential differences that would otherwise drive electrochemical reactions during high-field operation, proactively eliminating the degradation mechanism.
Solution Approach 2:
By connecting the GaN periphery to a reference potential layer through the conductive plug, the patent creates an equipotential condition at the die edge. This eliminates voltage gradients that would drive ionic migration and electrochemical reactions, allowing high electric fields to be applied in the active regions without causing peripheral degradation.
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 vertical leakage path significantly reduces lateral leakage currents, ensuring the die edge remains at ground potential, preventing electrochemical degradation and allowing for effective screening of defective parts during initial testing.
Implementation Method 1
An intentional vertical leakage path is created in the periphery of the semiconductor die using an uninsulated connection structure that extends vertically, providing a low-resistance path to ground, thereby shorting lateral leakage paths
Implementation Method 2
The combination of a high electric field and moisture leads to severe oxidation of the GaN or AlGaN surface layer, and therefore to destruction of the device. The reduction-oxidation (redox) reaction between an AlxGa1-xN surface layer and water is given by: 2AlxGa1-xN+3H2O=xAl2O3+(1−x)Ga2O3+N2⬆+3H2⬆
Data Source
AI summary
A method of manufacturing a semiconductor die includes forming a semiconductor body on a substrate. The semiconductor body has a periphery which is devoid of active devices and terminates at an edge face of the semiconductor die. The semiconductor body includes a first III-nitride semiconductor layer and a plurality of second III-nitride semiconductor layers below the first III-nitride semiconductor layer. The method further includes forming an uninsulated connection structure which extends vertically in the periphery of the semiconductor body and provides a vertical leakage path for at least some of the second III-nitride semiconductor layers either to the substrate or to a metallization layer disposed above the semiconductor body, but not to both. Additional semiconductor die manufacturing methods are provided.