III-V Nanosheet Channel Replacement on Silicon Substrates
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Solution Overview
Problem
Existing processes for fabricating III-V semiconductor devices are costly due to the use of indium phosphate substrates, which are more expensive than conventional silicon substrates, and there is a need for a method to efficiently form high-performance semiconductor devices with low power consumption.
Innovation Solution
A method involving the formation of a stack of alternating sacrificial layers with specific crystal orientations, where replacement channel layers are grown from the sidewalls of recessed sacrificial layers, and source/drain regions are epitaxially grown from these channel layers, allowing for the formation of III-V semiconductor devices on a group IV semiconductor substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indium phosphate substrates are used for fabricating III-V semiconductor devices, then device performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses conventional, inexpensive silicon substrates instead of expensive indium phosphate substrates. The silicon substrate serves as a temporary platform during fabrication, enabling cost-effective production while maintaining device performance through the replacement channel process.
Solution Approach 2:
The patent changes the substrate material parameter from indium phosphate to silicon, and modifies the crystal orientation parameter by forming (111) surfaces on silicon. This parameter change enables compatibility with standard silicon manufacturing processes while achieving the desired device performance.
2Ease of manufacture
If conventional silicon substrates are used, then manufacturing cost is reduced, but device performance deteriorates
Solution Approach 1:
The patent introduces sacrificial layers (silicon dioxide and silicon nitride) as intermediary structures. These layers mediate between the silicon substrate and the III-V semiconductor material, enabling the growth of high-performance III-V channels on cost-effective silicon substrates through selective epitaxial growth.
Solution Approach 2:
The patent segments the channel structure into multiple thin layers (first channel layer, second channel layer) grown on the silicon substrate. This segmentation allows precise control of material composition and crystal orientation, maintaining device performance while using silicon substrates.
3Manufacturing precision
If replacement channel layers are grown from sidewalls of sacrificial layers, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary actions by forming sacrificial layers with specific patterns and orientations before growing the replacement channel layers. The sacrificial layers are pre-configured with (111) crystal orientations and specific thicknesses to guide the subsequent epitaxial growth of III-V channels with precise control over their formation.
Solution Approach 2:
The patent employs self-aligned growth where the replacement channel layers automatically form on the sidewalls of the sacrificial layers through selective epitaxial growth. The sacrificial layers themselves serve as the template and guide for channel formation, eliminating the need for separate alignment steps and reducing process complexity.
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 cost-effective fabrication of high-performance III-V semiconductor devices with low power consumption by using conventional group IV semiconductor substrates, reducing material costs and improving device performance.
Implementation Method 1
Replacement channel layers are grown from sidewalls of the first sacrificial layers
Implementation Method 2
A first source/drain region is grown from the replacement channel layer
Data Source
AI summary
Semiconductor devices and methods of forming the same include forming a stack of alternating first and second sacrificial layers. The first sacrificial layers are recessed relative to the second sacrificial layers. Replacement channel layers are grown from sidewalls of the first sacrificial layers. A first source/drain region is grown from the replacement channel layer. The recessed first sacrificial layers are etched away. A second source/drain region is grown from the replacement channel layer. The second sacrificial layers are etched away. A gate stack is formed between and around the replacement channel layers.