Support Dielectric Fin for Stable Tall Nanosheet Gates
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Solution Overview
Problem
Nanosheet transistors face issues with mechanical instability, particularly gate flop-over, which limits the height-to-width ratio of gate structures and affects device performance.
Innovation Solution
Incorporating a support dielectric pillar adjacent to the active transistor fin to provide mechanical stability, using materials like SiCN, SiON, or SiBCN to form the pillar, which supports the active fin and prevents flop-over during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gate structures are made taller to improve device performance, then transistor performance is improved, but mechanical stability deteriorates causing gate flop-over
Solution Approach 1:
A support dielectric fin is introduced as an intermediary structure between the substrate and the gate structure. This support fin provides mechanical stabilization to the gate, preventing flop-over while allowing the gate to maintain its taller profile for improved performance. The support fin acts as a mediator that resolves the conflict between gate height and structural stability.
Solution Approach 2:
The gate structure is formed as a composite system combining the active transistor fin, the support dielectric fin, and the gate material. The support fin uses dielectric materials (such as silicon nitride, silicon oxide, or silicon oxynitride) that provide mechanical strength and stability, while the active fin provides electrical functionality. This composite structure enables both tall gates for performance and structural stability.
2Power
If gate structures are made taller, then device performance is improved, but manufacturing precision deteriorates due to difficulty in controlling gate profiles
Solution Approach 1:
The support dielectric fin serves as a mechanical scaffold that simplifies the formation of tall gate structures. By providing this underlying support, the manufacturing process can more easily control the gate profile without the gate collapsing or deforming during fabrication. The support fin acts as a template that guides precise gate formation.
Solution Approach 2:
The support dielectric fin is formed before the gate structure is deposited. This preliminary action creates a stable foundation that facilitates subsequent gate formation processes. By preparing the support structure in advance, the manufacturing process can achieve better precision when forming the actual gate, as the support fin prevents deformation during material deposition and patterning steps.
Data Source
AI summary
One or more systems, devices, and/or methods of fabrication provided herein relate to nanosheet transistors with support dielectric pillars. According to one embodiment, a transistor device can comprise an active transistor fin and a support dielectric pillar located adjacent to the active transistor fin, wherein the support dielectric pillar stabilizes the active transistor fin.