Fin Forced Stack Inverter for High Integration Density
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Solution Overview
Problem
The challenge in MOSFET development is to suppress the short channel effect while maintaining high current drive power, which is difficult to achieve with the reduction in MOSFET dimensions, especially in achieving efficient integration in LSI devices.
Innovation Solution
A 1-1 fin forced stack inverter is formed by arranging fins across active areas and performing a fin remove inside active process to remove part of the fins, followed by forming a gate across the remaining fins, thereby reducing the surface area and enhancing integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dimension of MOSFET is reduced according to scaling rule, then integration density is improved, but short channel effect increases and current drive power decreases
Solution Approach 1:
The patent transitions from planar MOSFET structure to vertically stacked FINFET structure, moving from two-dimensional to three-dimensional architecture. Multiple fins are stacked vertically to increase effective channel width and current drive capability while maintaining small footprint, thus improving integration density without sacrificing short channel effect control
Solution Approach 2:
The channel is divided into multiple independent fins stacked vertically, with each fin providing separate current path. This segmentation allows increased total channel width (improving current drive) while each individual fin maintains good gate control (suppressing short channel effect), resolving the contradiction between integration density and device performance
2Power
If more fins are arranged in active area, then current drive power is improved, but surface area increases
Solution Approach 1:
Instead of arranging fins horizontally in the plane, the patent stacks fins vertically in the third dimension. This allows multiple fins (increasing current drive power) to be contained within a small footprint area, effectively resolving the contradiction between power and surface area
Solution Approach 2:
Multiple fins are nested vertically one above another in the same lateral footprint, similar to nested dolls. This nesting arrangement maximizes the use of vertical space to accommodate more fins (higher current drive) without increasing the horizontal surface area occupied by the device
Data Source
AI summary
A method of forming a fin forced stack inverter includes the following steps. A substrate including a first fin, a second fin and a third fin across a first active area along a first direction is provided, wherein the first fin, the second fin and the third fin are arranged side by side. A fin remove inside active process is performed to remove at least a part of the second fin in the first active area. A first gate is formed across the first fin and the third fin in the first active area along a second direction. The present invention also provides a 1-1 fin forced fin stack inverter formed by said method.