Semiconductor Isolation Structure for Mobile Ion Blocking
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Solution Overview
Problem
Power semiconductor devices exhibit insufficient robustness against mobile ions during standardized tests like HTRB and H3TRB, leading to device failure.
Innovation Solution
A semiconductor device design featuring a substrate with an isolation region and a charge shielding layer having a sloped sidewall, combined with a metal barrier layer, which prevents mobile ion diffusion and enhances the conformal deposition of the metal barrier layer, thereby improving device robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional isolation region structure is used, then the device structure is simple, but the device shows insufficient robustness against mobile ions causing failure
Solution Approach 1:
The isolation region is segmented into a lower portion and an upper portion that protrudes from the lower portion. This segmentation creates a structured isolation region that effectively blocks mobile ion diffusion paths while maintaining manageable structural complexity
Solution Approach 2:
A charge shielding layer is introduced as an intermediary component between the isolation region and the metal barrier layer. This charge shielding layer with its specific sloped sidewall structure serves as a mediator that enhances the overall effectiveness of preventing mobile ion diffusion while enabling conformal deposition of the metal barrier layer
2Manufacturing precision
If the charge shielding layer has a vertical sidewall, then the deposition process is simpler, but the metal barrier layer cannot be conformally deposited
Solution Approach 1:
The sidewall angle of the charge shielding layer is changed from a vertical configuration to a sloped configuration with an angle of equal to or less than 50 degrees. This parameter change in the geometric configuration enables conformal deposition of the metal barrier layer while the etching process is adjusted to achieve this specific angle
3Reliability
If the isolation region is flat, then the manufacturing process is simpler, but the device lacks improved voltage blocking capability and area efficiency
Solution Approach 1:
The isolation region transitions from a flat two-dimensional structure to a three-dimensional structure with an upper portion that protrudes from the lower portion. This dimensional change creates additional voltage blocking capability and improves area efficiency while maintaining manageable manufacturing 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 semiconductor device demonstrates improved resistance to degradation and failure, ensuring reliable operation over its specified lifetime with enhanced voltage blocking capability and area efficiency.
Implementation Method 1
a charge shielding layer formed over at least a part of the upper portion of the isolation region... prevents mobile ion diffusion
Implementation Method 2
enhances the conformal deposition of the metal barrier layer... a metal barrier layer formed over at least a part of the charge shielding layer and over at least a part of the lower portion of the isolation region
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate and an isolation region at a first main surface of the substrate. The isolation region includes a lower portion and an upper portion that protrudes from the lower portion. The semiconductor device further includes a charge shielding layer over at least a part of the upper portion of the isolation region. An edge of the charge shielding layer has a sidewall which slopes inward at a first angle of equal to or less than 50 degrees. The semiconductor device further includes a metal barrier layer over at least a part of the charge shielding layer and over at least a part of the lower portion of the isolation region. A method of manufacturing the semiconductor device is also described.