FinFET Gate Electrode Mechanical Stability via Spacer Support
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Solution Overview
Problem
As semiconductor devices are scaled, FinFET gate electrodes become mechanically unstable due to the challenge of wrapping thin and tall gate electrodes around high aspect fins, leading to reduced mechanical stability.
Innovation Solution
The use of spacers formed along the sidewalls of the gate opening before the gate electrode is created, which increases mechanical stability and allows for smaller gate dimensions by providing support and reducing the height of the gate electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If gate electrodes are scaled down to achieve smaller dimensions, then device miniaturization is improved, but mechanical stability of the gate electrode deteriorates
Solution Approach 1:
A spacer layer is introduced as an intermediary structural element between the substrate and the gate electrode. This spacer provides mechanical support to the scaled-down gate electrode, preventing collapse while maintaining the reduced dimensions. The spacer acts as a mediator that enables small gate dimensions without sacrificing structural integrity.
Solution Approach 2:
The spacer layer is formed prior to depositing the gate electrode material. This preliminary structural preparation creates a stable foundation that supports subsequent gate electrode formation at reduced dimensions, preventing mechanical instability before it occurs during the scaling process.
2Length of moving object
If gate electrodes are made thinner to achieve smaller dimensions, then device scaling is improved, but mechanical stability deteriorates
Solution Approach 1:
The spacer layer serves as a mechanical intermediary that compensates for the reduced thickness of the gate electrode. By providing additional structural support from beneath, the spacer enables thin gate electrodes to maintain sufficient mechanical strength despite their reduced cross-sectional dimensions.
3Length of stationary object
If gate electrodes are made taller to maintain aspect ratio, then structural integrity is improved, but mechanical stability deteriorates due to wrapping around high aspect fins
Solution Approach 1:
The spacer layer is deposited before gate electrode formation, creating a preliminary support structure that prevents the gate electrode from collapsing during the wrapping process around high aspect fins. This advance preparation eliminates the need to increase gate height for structural integrity.
Data Source
AI summary
A method for forming a semiconductor device includes providing a semiconductor layer, forming a passivation layer over the semiconductor layer, wherein the passivation layer has an opening having sidewalls, forming a fin over the semiconductor layer, wherein after forming the passivation layer the fin is within the opening, and forming a portion of a gate within the opening. In one embodiment, a dummy gate is used. In one embodiment, spacers are formed within the opening of the passivation layer. The structure is also discussed.