Composite Semiconductor Substrate With Junction-Free Well Isolation
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Solution Overview
Problem
Conventional CMOS technologies face challenges with p/n-junction isolations, leading to latch-up issues, inefficient thermal dissipation, and noise disturbances due to incomplete well isolations, which become exacerbated as device geometries shrink and power dissipation increases.
Innovation Solution
The implementation of a composite semiconductor substrate using Deep-well-Trench-Isolation (DWTI) and Horizontal-well-Isolation (HWI) structures, eliminating p/n-junctions and employing high-thermal-conductivity materials to fully isolate wells and improve thermal dissipation, while allowing for scalable and mechanically robust designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If p/n-junction isolation is used in conventional CMOS, then electrical isolation between wells is achieved, but latch-up problems and noise disturbances occur due to incomplete isolation
Solution Approach 1:
The isolation structure is segmented into two distinct components: Deep-well-Trench-Isolation (DWTI) extending vertically into the substrate and Horizontal-well-Isolation (HWI) running horizontally between wells. This segmentation allows each component to address specific isolation needs, with DWTI providing deep vertical isolation to prevent latch-up and HWI providing horizontal separation to minimize noise coupling, achieving complete electrical isolation without the harmful effects of conventional p/n-junction isolation
Solution Approach 2:
The invention transitions from conventional single-plane isolation to a three-dimensional isolation architecture. DWTI addresses the vertical dimension by extending deep into the substrate to isolate wells from the bulk, while HWI addresses the horizontal dimension by separating adjacent wells laterally. This multi-dimensional approach ensures complete electrical isolation and eliminates latch-up problems that cannot be fully addressed by traditional two-dimensional isolation schemes
2Productivity
If conventional CMOS scaling is pursued, then device density increases, but thermal dissipation becomes insufficient due to increased power dissipation
Solution Approach 1:
A dedicated thermal management layer is introduced as an intermediary component between the active CMOS devices and the substrate. This layer, positioned within the DWTI structure, serves as a thermal conduit that efficiently conducts heat away from the densely packed devices, enabling continued scaling while maintaining acceptable thermal conditions through enhanced heat sinking capabilities
3Reliability
If triple well formation process is used, then complex electrical isolation is achieved, but process complexity and manufacturing steps increase
Solution Approach 1:
The invention merges the isolation functions into a unified DWTI-HWI structure that combines deep vertical isolation and horizontal isolation into a single integrated architecture. This eliminates the need for separate triple well formation processes and multiple discrete isolation steps, reducing process complexity while achieving complete electrical isolation and eliminating latch-up problems through the synergistic combination of vertical and horizontal isolation components
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
This approach significantly reduces latch-up problems, minimizes leakage, enhances thermal dissipation, and improves scalability and mechanical strength, enabling more efficient and stable CMOS device operations without the need for complex triple well formations.
Implementation Method 1
A combination of the deep well trench isolation region and the horizontal well isolation region fully isolates the first well region from other portion of the bulk semiconductor substrate
Implementation Method 2
either the deep well trench isolation region or the horizontal well isolation region includes a high-thermal-conductivity material which has a thermal conductivity higher than that of the SiO2 or silicon
Data Source
AI summary
A composite semiconductor substrate includes a bulk semiconductor substrate and a first well region. The bulk semiconductor substrate has an original semiconductor surface and with a first doping type. The first well region is in the bulk semiconductor substrate with a second doping type, wherein the first doping type is different from the second doping type. There is no PN junction between the bulk semiconductor substrate and the first well region.