Gate Cut Confinement Within Gate Trenches for Transistor Isolation
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Solution Overview
Problem
As integrated circuits scale down in size, forming gate cuts to isolate adjacent transistors becomes challenging due to uneven heights and detrimental impact on conductive features, leading to poor yield in existing fabrication techniques.
Innovation Solution
The formation of gate cuts is confined within the gate trench using a dielectric liner and fill, with anisotropic etching to create a recess and subsequent deposition of dielectric materials, ensuring the gate cut does not extend beyond the trench boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate cuts are formed using conventional fabrication techniques, then transistor isolation is achieved, but uneven heights and detrimental impact on conductive features occur leading to poor yield
Solution Approach 1:
The gate trench is formed and filled with dielectric material before the gate structure is completely formed. This preliminary action allows the gate cut to be defined within the trench boundaries, preventing subsequent damage to conductive features and improving fabrication yield while maintaining proper transistor isolation.
Solution Approach 2:
A dielectric liner is deposited within the gate trench to serve as an intermediary structure. This liner defines the boundaries of the gate cut and prevents the isolation structure from extending beyond the trench, thereby avoiding detrimental impacts on adjacent conductive features while achieving effective transistor isolation.
2Productivity
If device spacing is reduced to pack transistors more densely, then circuit density increases, but formation of isolation structures becomes challenging
Solution Approach 1:
The gate cut structure is nested within the gate trench, with the dielectric liner and fill material contained inside the trench boundaries defined by spacer structures. This nesting approach allows dense packing of transistors while maintaining proper isolation formation, as the gate cut is self-contained within the trench and does not interfere with adjacent devices.
Solution Approach 2:
The gate spacer structures automatically define the boundaries of the gate trench, which in turn confines the gate cut. This self-service mechanism eliminates the need for separate alignment steps to define gate cut boundaries, simplifying the fabrication process and enabling easier formation of isolation structures even at reduced device spacings.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for precise isolation of gate structures without affecting other conductive features, improving yield and reliability in semiconductor device fabrication.
Implementation Method 1
anisotropic etching to create a recess
Implementation Method 2
subsequent deposition of dielectric materials
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
Techniques are provided herein to form semiconductor devices that include one or more gate cuts that are self-aligned within the gate trench between adjacent devices. A semiconductor device includes a gate structure around or otherwise on a semiconductor region. The gate structure includes a gate dielectric and a gate electrode. The gate structure is interrupted with a gate cut that extends through an entire thickness of the gate structure and includes dielectric material to electrically isolate the portions of the gate structure on either side of the gate cut. The gate cut is confined within the gate trench such that it does not extend beyond the walls of the gate trench as defined by gate spacer structures. Additionally, the gate dielectric does not extend on any surface of the gate cut, such that the gate cut directly contacts the gate electrode.