Staggered Semiconductor Contact Structure Preventing Silicon Diffusion
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Solution Overview
Problem
High voltage and high power semiconductor devices, such as IGBTs, face electrical and mechanical challenges due to additional metal layers which can interact negatively with the underlying semiconductor substrate during thermal processes, leading to damage and deterioration of electrical characteristics.
Innovation Solution
A semiconductor device structure with a first and second insulator layer and corresponding contact layers, where the second contact layer is laterally displaced from the first, creating a staggered configuration that prevents unacceptable interdiffusion and provides a robust, mechanically stable contact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional metal layers are added to form robust press pack connections, then mechanical strength and electrical contact are improved, but silicon atom diffusion into the metal layers occurs during thermal processing, deteriorating electrical characteristics
Solution Approach 1:
An insulating layer is introduced as an intermediary between the semiconductor substrate and the metal contact layers. This intermediate layer acts as a diffusion barrier that prevents silicon atoms from migrating into the metal layers during thermal processing, while still allowing the metal layers to provide robust mechanical contact. The insulating layer thus mediates between the conflicting requirements of mechanical strength and electrical characteristic stability.
Solution Approach 2:
The contact structure is segmented into distinct functional layers: a lower metal layer for electrical contact, an insulating layer for diffusion protection, and an upper metal layer for mechanical strength. This segmentation allows each layer to perform its specific function without interfering with the others, particularly preventing the harmful interaction between silicon and metal while maintaining both electrical and mechanical performance.
2Strength
If additional metal layers are added to form robust press pack connections, then mechanical strength is improved, but the device complexity increases
Solution Approach 1:
The contact structure is divided into distinct functional segments: lower and upper metal layers separated by an insulating layer. This segmentation allows each layer to be optimized for its specific function while maintaining overall structural simplicity. The clear functional division makes the structure easier to manufacture and understand compared to a monolithic complex metallization scheme.
Solution Approach 2:
The contact structure employs a composite layered architecture combining insulating and conductive materials. This composite approach provides both mechanical strength and diffusion protection through a relatively simple layered configuration, avoiding the need for complex single-material solutions or intricate multi-layer metallization schemes.
3Device complexity
If the second contact layer is directly positioned over the first contact aperture, then electrical connection is simplified, but silicon diffusion into the contact layer occurs during thermal treatment
Solution Approach 1:
The insulating layer serves as a protective intermediary positioned between the semiconductor substrate and the upper metal contact layer. During thermal treatment, this intermediate layer blocks the diffusion path of silicon atoms, preventing them from reaching and contaminating the upper contact layer. The insulating layer thus mediates the harmful diffusion process while allowing the simplified direct positioning of contact layers to be maintained.
Solution Approach 2:
The problem of silicon diffusion is solved by introducing a protective dimension - the insulating layer in the vertical stacking direction. This additional dimensional element (the insulating barrier layer) blocks the diffusion path without requiring lateral displacement or complex routing, thus maintaining structural simplicity while effectively preventing harmful diffusion.
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
This configuration effectively prevents silicon atom diffusion into the contact layer during thermal treatments, maintaining the integrity of electrical characteristics and enhancing the reliability of semiconductor devices in high voltage and high current applications.
Implementation Method 1
a first insulator layer, disposed on a surface of the semiconductor device, and comprising a first contact aperture, disposed within the first insulator layer
Implementation Method 2
a first contact layer, comprising a first electrically conductive material, disposed over the insulator layer, and being in electrical contact with the semiconductor device through the first contact aperture
Data Source
AI summary
A semiconductor device structure may include a semiconductor device, disposed at least in part in a semiconductor substrate, and a first insulator layer, disposed on a surface of the semiconductor device, and comprising a first contact aperture, disposed within the first insulator layer. The semiconductor device structure may also include a first contact layer, comprising a first electrically conductive material, disposed over the insulator layer, and being in electrical contact with the semiconductor device through the first contact aperture, and a second insulator layer, disposed over the first contact layer, wherein the second insulator layer further includes a second contact aperture, displaced laterally from the first contact aperture, by a first distance. The semiconductor device structure may further include a second contact layer, comprising a second electrically conductive material, disposed over the second insulator layer, and electrically connected to the semiconductor device through the first and second contact aperture.