FinFET Matched Capacitors Using Shared Fin Structures
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Solution Overview
Problem
Existing semiconductor devices face challenges in fabricating matched capacitors with identical capacitance values, which is crucial for devices handling analog signals, due to variations in capacitor area, silicon doping, and dielectric thickness.
Innovation Solution
The method involves forming matched metal-oxide-semiconductor capacitors (MOSCaps) using FinFET techniques, where a common semiconductor fin structure and shared source and drain regions ensure identical capacitance properties, with conductive gates and insulators deposited in a three-dimensional structure to maintain chemical and physical similarity across capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional capacitor fabrication methods are used, then manufacturing process is simpler, but capacitor matching precision deteriorates due to variations in area, doping, and dielectric thickness
Solution Approach 1:
The patent merges the capacitor fabrication process with the FinFET transistor fabrication process. The capacitors share common structures (fin structure, source/drain regions, insulator layers, conductor layers) with the transistors, so that a single fabrication process simultaneously creates both functional devices with high matching precision without requiring separate processing steps.
Solution Approach 2:
The insulator layers and conductor layers are designed to serve dual functions: they form the gate structure for FinFET transistors and simultaneously form the capacitor structure (insulator structure and conductor structure) for capacitors. This multi-functionality ensures that both devices are fabricated with identical process parameters, achieving high matching precision.
2Manufacturing precision
If separate capacitor fabrication processes are used, then device functionality is more flexible, but manufacturing precision deteriorates due to process variations
Solution Approach 1:
The patent combines capacitor and transistor fabrication into a unified process where the same deposition and etching steps create both device types. This merging ensures that capacitors and transistors are manufactured under identical conditions, achieving high matching precision while maintaining the ability to design different device configurations.
Solution Approach 2:
The unified fabrication process is segmented into distinct functional regions: some regions are configured to form FinFET transistors while adjacent regions are configured to form capacitors. The segmentation allows both device types to coexist on the same substrate, manufactured with the same precision while maintaining design flexibility for different circuit configurations.
Data Source
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AI summary
Disclosed are various embodiments of FinFET semiconductor devices. A pair of matched capacitors can be formed that share a common source, drain and/or channel. Accordingly, the capacitance characteristics of each capacitor can be manufactured such that they are similar to one another. A resistor manufactured by employing FinFET techniques is also described. The resistor can be manufactured with an effective length that is greater than a distance traversed along a substrate by the resistor.