FinFET Channel Height Segmentation for Mobility and Leakage Control
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Solution Overview
Problem
Current semiconductor devices face challenges in optimizing channel region dimensions and strain levels to enhance mobility and reduce leakage, as existing methods do not effectively balance active region heights and channel region characteristics for improved performance.
Innovation Solution
The method involves forming a semiconductor device with a fin structure that includes a channel portion and active areas, where the channel portion has a recessed height greater than the active areas, and active regions are formed with specific heights and widths to induce increased strain, thereby enhancing electron and hole mobility and reducing source-drain leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the channel region height is increased to reduce source-drain leakage, then leakage is reduced, but mobility deteriorates due to increased strain
Solution Approach 1:
The device is segmented into distinct regions with different heights: the channel region maintains a first height optimized for mobility, while the active regions are formed at a second height greater than the channel height. This segmentation allows each region to be independently optimized - the channel for low leakage and the active regions for high mobility - resolving the contradiction between leakage reduction and mobility maintenance.
Solution Approach 2:
Different regions of the device are given different local properties: the channel region has a specific height and strain level optimized for leakage control, while the active regions have increased height and modified strain characteristics optimized for carrier mobility. This local differentiation allows simultaneous optimization of both leakage and mobility that would be impossible with a uniform structure.
2Reliability
If strain is increased to enhance mobility, then mobility is improved, but leakage increases due to altered channel characteristics
Solution Approach 1:
The device structure is divided into channel and active regions with different heights and strain levels. The channel region maintains strain levels that control leakage, while the active regions incorporate higher strain for mobility enhancement. This spatial segmentation of strain levels allows both contradictory requirements to be satisfied in different locations.
Solution Approach 2:
Strain is applied locally with different magnitudes in different regions: moderate strain in the channel region for leakage control and enhanced strain in the active regions for mobility improvement. This local quality differentiation resolves the contradiction by allowing high mobility where needed without compromising leakage control in the channel.
3Reliability
If active region height is increased to improve mobility, then mobility is enhanced, but device complexity increases
Solution Approach 1:
The device is segmented into channel and active regions with different heights, achieved through selective epitaxial growth or selective removal techniques. This segmentation approach, while creating vertical complexity, maintains manufacturing feasibility by using established semiconductor fabrication processes to create the height difference between regions.
Solution Approach 2:
The height parameter is changed selectively in different regions through controlled epitaxial growth or etching processes. By changing the height parameter locally in the active regions while maintaining the channel region height, the patent achieves mobility enhancement through a controlled modification of a single geometric parameter using standard fabrication techniques.
Data Source
AI summary
A semiconductor device and methods of formation are provided. The semiconductor device includes a first active region having a first active region height and an active channel region having an active channel region height over a fin. The first active region height is greater than the active channel region height. The active channel region having the active channel region height has increased strain, such as increased tensile strain, as compared to an active channel region that has a height greater than the active channel region height. The increased strain increases or enhances at least one of hole mobility or electron mobility in at least one of the first active region or the active channel region. The active channel region having the active channel region height has decreased source drain leakage, as compared to an active channel region that has a height greater than the active channel region height.