Semiconductor Device with Nested Level-Shift and Isolation Regions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices with high withstand-voltage isolation regions and level-shift devices face challenges in reducing chip size while maintaining electrical isolation, leading to increased chip size due to the placement of level-shift devices outside the high withstand-voltage isolation region.
Innovation Solution
A semiconductor device with a P-type SOI substrate, featuring an N-type first region, annular trench, N-type second region, N-type third region, and P-type isolation region, where the level-shift device is formed within the N-type third region, and the P-type isolation region extends along the boundary between the third and first regions, ensuring electrical isolation through a combination of dielectric and P-type isolation structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the level-shift device is formed outside the high withstand-voltage isolation region, then electrical isolation is ensured, but chip size increases
Solution Approach 1:
The level-shift device is nested inside the high withstand-voltage isolation region by forming the N-type third region (level-shift device region) within the N-type first region (isolation region). This nested configuration allows the level-shift device to be positioned inside the isolation region, reducing chip size while maintaining electrical isolation through the P-type isolation region that extends along the boundary.
Solution Approach 2:
The P-type isolation region extends along the boundary between the N-type third region and the N-type first region in plan view, creating a dimensional barrier that ensures electrical isolation while allowing compact spatial arrangement. This boundary extension approach adds an isolating dimension without increasing overall chip footprint.
2Area of stationary object
If the level-shift device is formed inside the high withstand-voltage isolation region, then chip size is reduced, but electrical isolation may be compromised
Solution Approach 1:
The P-type isolation region is formed in advance along the boundary between the N-type third region and the N-type first region before final device operation. This preliminary isolation structure pre-establishes electrical separation, ensuring that when the level-shift device is formed inside the isolation region, electrical isolation is already in place and cannot be compromised by the device's position.
3Reliability
If the P-type isolation region extends along the boundary between the third and first regions, then electrical isolation is ensured, but device complexity increases
Solution Approach 1:
The P-type isolation region serves multiple functions simultaneously: it provides electrical isolation between the N-type third region (level-shift device) and the N-type first region (isolation region), and it extends along the boundary to maintain isolation effectiveness. This multi-functional design achieves reliable electrical isolation without requiring additional separate isolation structures, thereby limiting the increase in device complexity.
Data Source
AI summary
A semiconductor device includes a P-type low potential region, an N-type first region, an N-type second region, an N-type third region, an annular trench, and a P-type isolation region. The N-type first region is provided on the principal surface of a P-type SOI layer provided to a P-type SOI substrate. The N-type first region has a concave portion. The N-type third region is provided inside the concave portion of the N-type first region so as to be away from the edge of the concave portion. A level-shift device is formed on the surface of the N-type third region. The P-type isolation region is a slit region extending in U-shape along the boundary between the N-type third region and the concave portion of the N-type first region.