GAA Nanostructure Wall Layout for Tighter Gate-Cut Spacing
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Solution Overview
Problem
The integration of gate-all-around (GAA) devices in semiconductor manufacturing is challenging due to complexity in fabrication, particularly in achieving precise spacing and scaling down dimensions while maintaining gate control and mitigating short-channel effects.
Innovation Solution
A semiconductor structure is formed with self-aligned wall structures that minimize the spacing between active regions and gate-cut features, using photolithography and self-aligned processes to pattern nanostructures, which reduce total cell capacitance and enable scaling down of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fabrication methods are used for GAA devices, then manufacturing process complexity increases, but gate control and short-channel effect mitigation are compromised
Solution Approach 1:
The method performs preliminary patterning of the gate electrode and dielectric layers before forming the channel structure. By pre-positioning the gate elements and using self-aligned processes, the fabrication complexity is reduced while ensuring precise gate control over the channel region.
Solution Approach 2:
The patent employs self-aligned processes where previously formed structures automatically serve as alignment references for subsequent steps. The gate electrode and dielectric layers are positioned such that no additional alignment steps are needed, reducing process complexity while maintaining precise gate control.
2Productivity
If device dimensions are scaled down to improve production efficiency, then manufacturing costs decrease, but manufacturing precision requirements increase
Solution Approach 1:
Self-aligned processes are used where previously formed structures automatically serve as alignment references. The gate electrode and dielectric layers are positioned such that their relative locations are determined by the deposition and etching processes themselves, not by additional lithography alignment steps, thereby maintaining precision at scaled dimensions.
Solution Approach 2:
The method changes the approach from lithography-defined spacing to process-defined spacing. By controlling deposition thicknesses and etch depths, the spacing between features is determined by process parameters rather than optical resolution limits, enabling precise spacing at smaller dimensions.
3Area of stationary object
If spacing between active regions is reduced to increase device density, then area utilization improves, but gate control deteriorates
Solution Approach 1:
The gate electrode and dielectric layers are pre-positioned before channel formation, creating a preliminary gate structure that extends over the future channel region. This preliminary action ensures that even when active regions are closely spaced, the gate control is established before the channel is defined, maintaining effectiveness.
Solution Approach 2:
The gate structure is extended into the vertical dimension with dielectric layers positioned above and below the gate electrode. This three-dimensional gate configuration provides enhanced gate control over the channel region, allowing closer spacing of active regions while maintaining effective electrostatic control through the added vertical dimension.
Data Source
AI summary
A semiconductor structure is provided. The semiconductor structure includes a first plurality of nanostructures between a first source/drain feature and a second source/drain feature, a first gate segment surrounding the first plurality of nanostructures, and a wall structure abutting the first gate segment. A first nanostructure in the first plurality of nanostructures includes a bulk portion and a protrusion, and the protrusion protrudes from a first sidewall of the bulk portion toward the wall structure.