MOSFET Isolation Structure for Dense Semiconductor Integration
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Solution Overview
Problem
As semiconductor devices are scaled down, the operating characteristics of MOSFETs deteriorate, leading to challenges in manufacturing devices with excellent performance while overcoming integration limitations.
Innovation Solution
A semiconductor device is designed with a specific structure that includes a first active pattern, a second active pattern spaced apart at different distances, device isolation layers, channel structures, and a separation dielectric layer between the channel structures. This structure improves electrical properties and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size and design rule of semiconductor devices are decreased, then integration density increases, but operating characteristics of MOSFETs deteriorate
Solution Approach 1:
The device isolation structure is segmented into multiple layers: a first device isolation layer (51) and a second device isolation layer (52), with the separation dielectric layer (20) positioned between channel structures. This multi-layer segmentation allows for optimized electrical isolation at different spatial levels, maintaining MOSFET operating characteristics while enabling higher integration density through compact device spacing.
Solution Approach 2:
The separation dielectric layer (20) acts as an intermediary element positioned between adjacent channel structures (CH1, CH2, CH3, CH4). This intermediate layer provides electrical isolation and prevents interference between neighboring devices, enabling closer device spacing and higher integration density while maintaining reliable operation. The dielectric material serves as a mediator that resolves the conflict between proximity and electrical isolation.
2Productivity
If device spacing is reduced to increase integration density, then productivity improves, but electrical isolation between devices deteriorates
Solution Approach 1:
The isolation structure extends into the vertical dimension with two distinct device isolation layers (51, 52) at different elevation levels, in addition to the separation dielectric layer (20) between channel structures. This three-dimensional isolation architecture provides electrical isolation in multiple spatial dimensions, effectively blocking electrical interference even when devices are closely spaced horizontally, thus enabling high integration density without compromising electrical isolation.
Solution Approach 2:
The device isolation structure employs composite dielectric materials with different properties: the first device isolation layer (51) and second device isolation layer (52) use different dielectric materials, and the separation dielectric layer (20) uses yet another dielectric material. This composite material approach allows optimization of each layer for specific functions (e.g., stress control, electrical isolation, mechanical support), achieving superior overall performance in both integration density and electrical isolation.
Data Source
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AI summary
A semiconductor device may include a first active pattern, a second active pattern spaced apart at a first distance from the first active pattern, a third active pattern spaced apart at a second distance from the second active pattern, a first device isolation layer between the first and second active patterns, a second device isolation layer between the second and third active patterns, a first channel structure overlapping the first active pattern, a second channel structure overlapping the second active pattern, a third channel structure overlapping the third active pattern, and a separation dielectric layer between the first and second channel structures. The separation dielectric layer may overlap the first device isolation layer. A level of a top surface of the first device isolation layer may be higher than a level of a top surface of the second device isolation layer.