GAA Gate Stack Structure With Inner Spacers for Scaled Fin Reliability
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity and difficulty of fabrication processes as feature sizes continue to decrease.
Innovation Solution
The development of a gate all around (GAA) transistor structure is achieved through a method involving sacrificial layers and channel layers formed using epitaxial growth processes, followed by patterning and etching techniques to create fin structures and gate stacks, utilizing materials like SiGe and Si for sacrificial and channel layers, and high-k dielectric materials for insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple sequential stages including forming sacrificial layers, forming channel layers, patterning, etching, and gate stack formation. Each stage handles a specific aspect of the device structure, breaking down the complex process of creating sub-10nm features into manageable segments that can be executed with existing fabrication tools and techniques.
Solution Approach 2:
Sacrificial layers are formed in advance before the actual device structure is created. These preliminary layers serve as templates that guide subsequent patterning and etching steps, allowing precise feature formation without requiring direct manipulation of the final structure at such small dimensions.
2Area of stationary object
If feature sizes continue to decrease to increase functional density, then chip area utilization is improved, but manufacturing reliability deteriorates
Solution Approach 1:
Sacrificial layers act as intermediary structures that enable precise formation of channel layers and gate stacks at sub-10nm dimensions. These intermediate templates provide mechanical support and dimensional control during fabrication, ensuring manufacturing reliability while achieving high chip area utilization through dense feature packing.
Solution Approach 2:
The patent employs precise control of material deposition parameters, etching conditions, and layer thicknesses to maintain manufacturing reliability at reduced feature sizes. By optimizing parameters such as layer thickness, material composition, and process conditions, the invention achieves reliable device formation despite the challenges of scaling to smaller dimensions.
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 approach enables the formation of reliable semiconductor devices with precise control over feature sizes, enhancing production efficiency and reducing manufacturing costs by allowing for smaller and more complex circuit designs.
Implementation Method 1
a method involving sacrificial layers and channel layers formed using epitaxial growth processes
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate including a base and a fin structure over the base. The fin structure includes a nanostructure. The semiconductor device structure includes a gate stack over the base and wrapped around the nanostructure. The gate stack has an upper portion, a first sidewall portion, and a lower portion, the upper portion is over the nanostructure, the first sidewall portion is over a first sidewall of the nanostructure, the lower portion is between the base and the nanostructure, and the lower portion is wider than the first sidewall portion. The semiconductor device structure includes a first inner spacer and a second inner spacer over opposite sides of the first sidewall portion and under the upper portion.