Semiconductor Device Isolation Structure Segmentation
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Solution Overview
Problem
Conventional laterally diffused metal oxide semiconductor (LDMOS) devices have low on-current and high resistance, requiring more area, which is a challenge in designing semiconductor devices with limited size for high power and voltage applications.
Innovation Solution
The semiconductor device incorporates an active area structure with gates and isolation structures arranged in perpendicular directions, where the isolation structures are shorter than the active area width, and polysilicon structures connected across the active area to enhance on-current and prevent current concentration on silicide surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDMOS structure is used, then voltage resistance is achieved, but on-current is low and resistance is high
Solution Approach 1:
The isolation structures are segmented into multiple sections along the active area, with each section having a specific length that is shorter than the width of the active area in the second direction. This segmentation allows current to flow through multiple paths while maintaining voltage resistance, thereby improving on-current without sacrificing voltage withstand capability.
Solution Approach 2:
The patent applies different properties to different regions: silicide is applied to certain areas to reduce resistance and improve on-current, while isolation structures are strategically placed in specific locations to maintain voltage resistance. The selective application of silicide and isolation structures creates local quality variations that optimize both voltage resistance and on-current performance.
2Reliability
If conventional LDMOS structure is used, then voltage resistance is achieved, but device area is large
Solution Approach 1:
The patent introduces a second direction perpendicular to the first direction (along the active area), and places isolation structures with specific orientation and length in this second direction. By controlling the length of isolation structures in the second direction to be shorter than the active area width, the patent enables more efficient space utilization, reducing the overall device area while maintaining voltage resistance through the strategic placement of isolation structures.
3Reliability
If isolation structures are added to improve voltage resistance, then on-current is reduced due to current blocking
Solution Approach 1:
The isolation structures are designed with partial action - their length is specifically controlled to be shorter than the width of the active area in the second direction. This partial coverage allows the isolation structures to provide voltage resistance where needed while leaving gaps that allow current to flow through, thus maintaining on-current performance while achieving voltage resistance.
Data Source
AI summary
A semiconductor device includes an active area structure, at least one gate and at least one isolation structure. The active area structure is arranged along a first direction. The at least one gate is arranged above the active area structure and along a second direction. The second direction is different from the first direction. The at least one isolation structure is arranged in the active area structure. A length of the at least one isolation structure is shorter than a width of the active area structure in the second direction.