Nanosheet MEMS Sensor Integration with Transistors
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Solution Overview
Problem
Existing solutions for fabricating nanosheet transistors are not well-suited for integrating nanosheet field effect transistor (FET) devices and MEMS sensors, as they require separate fabrication processes and dedicated dies, leading to increased cost, complexity, and size of integrated circuit devices.
Innovation Solution
A nanosheet process flow is developed to integrate MEMS sensors with nanosheet transistors on the same die, using standard process steps that minimize additional processing effects on transistors, allowing dual use of fabrication steps and eliminating the need for new fabrication tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate fabrication processes and dedicated dies are used for nanosheet transistors and MEMS sensors, then manufacturing precision and device performance are maintained, but device complexity and fabrication cost increase
Solution Approach 1:
The patent merges the fabrication processes for nanosheet transistors and MEMS sensors into a single integrated process flow. Both device types are formed on the same die using shared process steps including silicon-silicon germanium layer deposition, selective etching, and spacer formation. This consolidation eliminates the need for separate fabrication processes and dedicated dies, reducing overall device complexity while maintaining manufacturing precision through standardized process steps.
Solution Approach 2:
The patent creates a universal nanosheet process flow that can fabricate both nanosheet transistors and MEMS sensors using the same sequence of steps. The process uses common materials (silicon and silicon germanium layers), common fabrication techniques (selective etching, spacer deposition), and a single die substrate for both device types, achieving multi-functionality in the fabrication system.
2Manufacturing precision
If separate fabrication processes are used for nanosheet transistors and MEMS sensors, then device performance is maintained, but fabrication cost increases
Solution Approach 1:
The patent combines the fabrication of nanosheet transistors and MEMS sensors into a single process flow on one die, eliminating duplicate fabrication steps. Shared process steps include the deposition of silicon and silicon germanium layers, selective etching to release MEMS structures, and spacer formation for both transistor gates and MEMS anchors. This merging reduces fabrication cost by eliminating redundant process steps and equipment usage.
3Manufacturing precision
If separate dedicated dies are used for nanosheet transistors and MEMS sensors, then device performance is maintained, but chip size increases
Solution Approach 1:
The patent merges nanosheet transistors and MEMS sensors onto a single die substrate, forming both device types within the same integrated structure. The nanosheet process flow creates transistor stacks and MEMS sensor stacks on the same die, sharing common process steps and materials. This consolidation significantly reduces the total chip area required compared to using separate dedicated dies for each device type.
4Adaptability or versatility
If new fabrication tools are introduced for MEMS sensor integration, then sensor functionality is achieved, but device complexity and cost increase
Solution Approach 1:
The patent achieves MEMS sensor functionality using the existing nanosheet fabrication toolset without introducing new specialized equipment. The same deposition, etching, and spacer formation tools used for nanosheet transistors are applied to create MEMS structures. This universal approach maintains sensor functionality while avoiding the complexity and cost associated with new fabrication tools.
Data Source
AI summary
A nanosheet MEMS sensor device and method are described for integrating the fabrication of nanosheet transistors (61) and MEMS sensors (62) in a single nanosheet process flow by forming separate nanosheet transistor and MEMS sensor stacks (12A-16A, 12B-16B) of alternating Si and SiGe layers which are selectively processed to form gate electrodes (49A-C) which replace the silicon germanium layers in the nanosheet transistor stack, to form silicon fixed electrodes using silicon layers (13B-2, 15B-2) on a first side of the MEMS sensor stack, and to form silicon cantilever electrodes using silicon layers (13B-1, 15B-1) on a second side of the MEMS sensor stack by forming a narrow trench opening (54) in the MEMS sensor stack to expose and remove remnant silicon germanium layers on the second side in the MEMS sensor stack.