Variable Height Substrate Fins for Drive Current Optimization
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Solution Overview
Problem
Multi-gate devices, such as transistors, face challenges in optimizing drive current without increasing transistor area, as the gate channel width is dependent on fin height, limiting the independent selection of transistor height and area for desired device characteristics.
Innovation Solution
The formation of fins with different heights on a substrate allows for the creation of multi-gate transistors with varying drive currents by selecting fin heights, enabling independent adjustment of transistor height and area to achieve desired device properties, using patterned mask layers and etching processes to achieve specific height differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fin height is increased to increase gate channel width and drive current, then drive current is improved, but transistor area increases
Solution Approach 1:
The patent applies local quality by creating fins with different heights at different locations on the substrate. Specifically, first fins have a first height while second fins have a second height that is greater than the first height. This allows different regions to have optimized characteristics for their specific function, enabling independent optimization of drive current without necessarily increasing overall transistor area.
Solution Approach 2:
The patent utilizes the vertical dimension by varying fin heights in the vertical direction rather than only in the horizontal plane. By creating height differentials in the vertical dimension, the gate channel width can be effectively increased for higher fins, thereby increasing drive current without proportionally increasing the planar footprint or transistor area.
2Adaptability or versatility
If fin height is varied to optimize device characteristics, then device performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the substrate into different regions with different fin heights. First fins are formed in a first region with a first height, while second fins are formed in a second region with a second height. This segmentation allows independent optimization of device characteristics in different regions while using standardized manufacturing processes for each segment.
Solution Approach 2:
The patent employs preliminary action through the use of mask layers before etching. A first mask layer is formed to protect regions where first fins will be formed, and a second mask layer is formed to protect regions where second fins will be formed. These preliminary masking steps define the fin height patterns before the etching process, simplifying the overall manufacturing by pre-establishing the selective protection scheme.
Data Source
AI summary
A device includes a number of fins. Some of the fins have greater heights than other fins. This allows the selection of different drive currents and/or transistor areas.