Nanowire GAA Transistor Structure to Reduce Voids and Short-Channel Effects
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing advanced semiconductor devices due to the increasing complexity and scaling down of integrated circuits, which requires more sophisticated processing and manufacturing techniques.
Innovation Solution
The development of a gate all around (GAA) transistor structure, which involves patterning semiconductor device structures using photolithography and self-aligned processes, forming a stack structure with alternating semiconductor layers, and creating source/drain portions to enhance carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If planar transistors are used in conventional IC structures, then manufacturing processes are simpler and easier to control, but device performance is limited and short channel effects are more pronounced
Solution Approach 1:
The patent transitions from planar (2D) transistor structures to three-dimensional nanowire structures with gate-all-around configuration. This dimensional change enables the gate to surround the channel in all directions, providing superior electrostatic control and reducing short channel effects while improving device performance without proportionally increasing manufacturing complexity
Solution Approach 2:
The patent employs alternating layers of different semiconductor materials (e.g., Si/SiGe) to form the nanowire stack structure. This composite material approach enables selective etching to create suspended nanowire channels while maintaining structural integrity, achieving both performance improvement and manufacturability
2Productivity
If geometric size is scaled down to increase functional density, then production efficiency increases and costs decrease, but processing and manufacturing complexity increases
Solution Approach 1:
The patent divides the transistor structure into segmented nanowire channels formed from alternating semiconductor layers. This segmentation allows independent control and optimization of different channel regions, enabling scaled-down geometries with maintained manufacturability through modular fabrication approaches
Solution Approach 2:
The patent forms the complete nanowire stack structure with alternating layers before any channel definition or gate formation steps. This preliminary structuring enables subsequent self-aligned processing and simplifies later fabrication steps, reducing overall processing complexity despite advanced scaling
3Reliability
If conventional transistor structures are used, then manufacturing processes are well-established and easier to control, but void formation occurs and structural reliability is reduced
Solution Approach 1:
The patent removes sacrificial layers (e.g., SiGe) from between the nanowire channels, creating suspended nanowire structures. This extraction eliminates void formation issues present in conventional structures while maintaining ease of manufacture through selective etching processes that are extensions of existing semiconductor fabrication techniques
Solution Approach 2:
The patent uses sacrificial layers as intermediary structures during fabrication. These temporary structures enable precise nanowire formation and alignment, then are removed to create the final suspended structure. This intermediary approach simplifies the overall manufacturing process by breaking down complex steps into manageable sequential operations
Data Source
AI summary
Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a plurality of nanostructures over a substrate, and a gate electrode surrounding the nanostructures. The semiconductor device structure includes a source/drain (S/D) portion adjacent to the gate electrode, and an interlayer dielectric layer adjacent formed over the source/drain portion. The semiconductor device structure includes an etch stop layer adjacent between the source/drain portion and the interlayer dielectric layer, and a protective element adjacent formed over the interlayer dielectric layer.