Gate Isolation Wall Structure for Nanostructure Transistor Uniformity
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Solution Overview
Problem
The challenges in semiconductor manufacturing include increased complexity and defects such as threshold voltage variations, metal gate extrusion, sidewall spacer damage, and electrical shorts in nanostructure transistors, which affect device performance and yield.
Innovation Solution
The introduction of a gate isolation wall and dielectric liner in semiconductor devices with nanostructure transistors, which includes a gate isolation structure to electrically isolate gate structures and improve threshold voltage uniformity, reduce metal gate extrusion defects, and prevent electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate structures are scaled down to increase storage capacity and processing speed, then device performance improves, but threshold voltage variations and electrical shorts increase
Solution Approach 1:
A gate isolation wall is introduced as an intermediary structure between adjacent gate structures. This isolation wall prevents direct electrical interaction between gates while maintaining proper spacing, thereby reducing threshold voltage variations and electrical shorts that occur when gates are scaled down closely together
Solution Approach 2:
The gate structure is segmented into separate isolated units by introducing gate isolation walls between adjacent gates. This segmentation allows each gate to be independently controlled and isolated, preventing electrical interference and maintaining uniform threshold voltage across scaled-down devices
2Quantity of substance
If gate structures are scaled down to increase storage capacity, then device density improves, but metal gate extrusion defects increase
Solution Approach 1:
The gate isolation wall is formed in advance before metal gate deposition and patterning processes. This preliminary structure prevents metal gate material from extruding between adjacent gates during subsequent processing steps, as the isolation wall creates a physical barrier that maintains proper spacing
Solution Approach 2:
The gate isolation wall is formed preliminarily to establish proper gate spacing before metal gate formation. This preliminary action ensures that when metal gates are later deposited and patterned at scaled dimensions, there is sufficient isolation to prevent extrusion defects
3Ease of manufacture
If manufacturing processes are simplified to reduce costs, then production efficiency improves, but sidewall spacer damage and electrical shorts increase
Solution Approach 1:
The gate isolation wall serves multiple functions simultaneously: it provides electrical isolation between gates, prevents sidewall spacer damage during processing, and maintains proper gate spacing. This multi-functionality allows a single structure to address multiple reliability issues without requiring additional complex process steps
Data Source
AI summary
The present disclosure describes a semiconductor device having an isolation structure. The semiconductor structure includes a set of nanostructures on a substrate, a gate dielectric layer wrapped around the set of nanostructures, a work function metal layer on the gate dielectric layer and around the set of nanostructures, and the isolation structure adjacent to the set of nanostructures and in contact with the work function metal layer. A portion of the work function metal layer is on a top surface of the isolation structure.