Engineered Multigate Structure for GAA Channel Control
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Solution Overview
Problem
Existing gate-all-around (GAA) devices face challenges in fabrication that degrade performance and increase processing complexity, hindering the development of advanced integrated circuits.
Innovation Solution
A method for fabricating multigate devices, including GAA transistors, involves forming semiconductor layers with nonuniform composition and patterning them to create fins with specific profiles, followed by the formation of gate structures that wrap around the channels, optimizing source/drain features for reduced parasitic capacitance and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional IC scaling is continued to reduce minimum feature size, then production efficiency improves and costs decrease, but manufacturing process complexity increases
Solution Approach 1:
The patent transitions from planar 2D gate structures to three-dimensional gate-all-around structures that wrap completely around the channel region. This dimensional change enables better gate control and electrostatic management while maintaining compatibility with scaled dimensions, thereby improving productivity without proportionally increasing manufacturing complexity
Solution Approach 2:
The gate structure is designed to nest around the channel region in a gate-all-around configuration, with the gate wrapping completely around the channel on all sides. This nested architecture provides superior gate control and electrostatics while maintaining a compact footprint that supports continued IC scaling
2Reliability
If gate-all-around structures are implemented to improve gate control, then gate-channel coupling increases and short-channel effects are reduced, but fabrication challenges arise that degrade device performance
Solution Approach 1:
The fabrication process is divided into distinct sequential stages: forming the channel structure first, then depositing gate materials conformally around it, followed by separate steps for source/drain formation and interconnect integration. This segmentation allows each component to be optimized independently while maintaining the overall gate-all-around architecture
Solution Approach 2:
The channel structure is formed and positioned before the gate materials are deposited around it. This preliminary action ensures proper alignment and spacing are established early in the process, enabling subsequent gate formation steps to achieve the required precision without compounding tolerances
3Reliability
If gate-all-around structures are implemented to improve gate control, then processing complexity increases
Solution Approach 1:
The gate-all-around structure serves multiple functions simultaneously: it provides gate control, acts as an interconnect barrier, defines the active channel region, and enables electrostatic management. This multi-functionality reduces the need for separate dedicated structures, thereby managing processing complexity while achieving superior gate control
Solution Approach 2:
The gate structure is merged with the interconnect barrier function, where the same gate-all-around structure that provides channel control also serves as the barrier for adjacent interconnect lines. This merging eliminates the need for separate barrier structures, reducing overall processing complexity
Data Source
AI summary
The present disclosure provides one embodiment of a semiconductor structure. The semiconductor structure includes a fin region formed on a substrate, wherein the fin region includes multiple channels vertically stacked on the substrate; a gate stack disposed on the fin region, wherein the gate stack is wrapping around each of the multiple channels and includes gate extensions being extending laterally to be overlapped with inner spacers; and a pair of source/drain (S/D) features formed on the fin region, interposed by the gate stack, and connected with the multiple channels.