High-Voltage Drift Region Insulation for Silicide-Free Breakdown Control
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Solution Overview
Problem
Conventional high voltage semiconductor devices face challenges in improving electrical performance and integrating with other components due to shrinking feature sizes, particularly in preventing the formation of silicide layers on drift regions which affect breakdown voltage and efficiency.
Innovation Solution
A high voltage semiconductor device design that includes an insulation structure connected directly with the drift region, preventing the formation of silicide layers between specific components, thereby enhancing electrical performance by reducing off-current and improving integration with other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicide layer is formed on the drift region to improve conductivity, then electrical conductivity is improved, but breakdown voltage decreases and electrical performance deteriorates
Solution Approach 1:
The patent applies different treatments to different regions of the drift region: silicide is formed on source/drain regions for low resistance contact, while the drift region itself remains free of silicide to maintain high breakdown voltage. This is achieved through selective masking and patterning processes that prevent silicide deposition only on the drift region.
Solution Approach 2:
The patent introduces an intermediate insulating layer between the drift region and the silicide formation process. This insulating layer acts as a barrier that prevents direct contact between metal and silicon during silicide formation, thereby preventing harmful silicide layer formation on the drift region while allowing silicide formation on other regions.
2Productivity
If feature size is reduced to improve integration density, then integration capability is improved, but electrical performance of high voltage units deteriorates
Solution Approach 1:
The patent maintains different structural characteristics in different regions: the drift region keeps its original large-area, low-doping structure for high voltage performance, while other regions are scaled down for high integration density. This allows simultaneous achievement of high voltage capability and high integration density through selective scaling.
Solution Approach 2:
The patent segments the device structure into distinct functional regions with different scaling requirements. The drift region is kept separate and unscaled to maintain electrical performance, while surrounding regions are scaled for integration density. This segmentation allows independent optimization of each region for its specific function.
3Ease of manufacture
If conventional manufacturing process is used to simplify fabrication, then manufacturing complexity is reduced, but precision in preventing silicide formation deteriorates
Solution Approach 1:
The patent performs preliminary patterning of the drift region before the silicide formation process. By pre-defining the drift region boundaries with insulating layers or masks, the subsequent silicide formation process automatically excludes the drift region without requiring additional precision control steps, thus maintaining manufacturing simplicity while achieving precise silicide placement.
Data Source
AI summary
A high voltage semiconductor device includes a semiconductor substrate, a first drift region, a gate structure, a first sub gate structure, a first spacer structure, a second spacer structure, and a first insulation structure. The first drift region is disposed in the semiconductor substrate. The gate structure is disposed on the semiconductor substrate and separated from the first sub gate structure. The first sub gate structure and the first insulation structure are disposed on the first drift region. The first spacer structure is disposed on a sidewall of the gate structure. The second spacer structure is disposed on a sidewall of the first sub gate structure. At least a part of the first insulation structure is located between the first spacer structure and the second spacer structure. The first insulation structure is directly connected with the first drift region located between the first spacer structure and the second spacer structure.