Semiconductor Structure With Diffusion Barrier Layer
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Solution Overview
Problem
The scaling down of laterally diffused metal oxide semiconductors (LDMOS) is limited due to dopant diffusion from conductive features, which affects electrical properties and prevents further reduction in source-drain resistance, hindering performance enhancement.
Innovation Solution
A semiconductor structure with a diffusion barrier layer, comprising dielectric barrier layers such as a barrier oxide and nitride layer, is introduced between the conductive feature and the epitaxial layer to prevent dopant diffusion, and the conductive feature is designed with a protruding portion to prevent seam formation and enhance current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of LDMOS is reduced to enhance performance, then the source-drain resistance can be reduced, but dopant diffusion from the conductive feature to peripheral elements becomes more significant and negatively affects electrical properties
Solution Approach 1:
A diffusion barrier layer is introduced as an intermediary between the conductive feature and the epitaxial layer to block dopant diffusion. This mediator prevents the harmful interaction between the conductive feature and peripheral elements, allowing device scaling without compromising electrical properties of LDMOS.
Solution Approach 2:
The conductive feature is segmented into two parts: a lower conductive portion embedded in the epitaxial layer and an upper protruding portion extending above it. This segmentation allows the lower portion to provide electrical connection while the upper portion, separated by the diffusion barrier layer, prevents dopant diffusion to peripheral elements.
2Reliability
If a diffusion barrier layer is introduced to prevent dopant diffusion, then electrical properties are maintained, but the device structure becomes more complex
Solution Approach 1:
The diffusion barrier layer is implemented as a thin film structure that can be conformally deposited on the sidewalls of the conductive feature. This thin film approach provides effective dopant blocking while minimizing the additional space required, thus limiting the increase in device complexity.
3Productivity
If the conductive feature is designed with a protruding portion higher than the epitaxial layer, then seam formation is prevented and current flow is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The protruding portion of the conductive feature is formed before subsequent processing steps. This preliminary formation ensures that the conductive feature already has the optimal geometry for preventing seam formation and enhancing current flow before other device components are added, simplifying the overall manufacturing sequence.
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 diffusion barrier layer effectively blocks dopant diffusion, allowing for further scaling of LDMOS without impacting electrical properties, and the protruding conductive feature design prevents seam-related issues, enabling reduced source-drain resistance and improved performance.
Implementation Method 1
a diffusion barrier layer disposed on sidewalls of the conductive feature
Data Source
AI summary
A semiconductor structure includes a substrate, an epitaxial layer disposed on the substrate, a conductive feature disposed in the epitaxial layer having a protruding portion that is higher than the epitaxial layer, and a diffusion barrier layer disposed on sidewalls of the conductive feature.