Conductor-Insulator-Conductor Capacitor Sidewall Encapsulation
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Solution Overview
Problem
In integrated circuits, capacitors with single-crystalline silicon or polysilicon electrodes face instability due to depletion regions when a bias voltage is applied, leading to unpredictable capacitance, and existing MIM capacitors have limitations in capacitance density as semiconductor devices shrink and integrate more densely.
Innovation Solution
A conductor-insulator-conductor capacitor design with a stepped structure and multiple conductive and insulating layers, where the outer electrode surrounds and encapsulates the inner electrode, enhancing capacitance density by increasing the area of the conductive layers and using high-k materials for the insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-crystalline silicon or polysilicon electrodes are used in capacitors, then the capacitor can be integrated with existing semiconductor processes, but a depletion region forms when bias voltage is applied causing unstable capacitance
Solution Approach 1:
The patent changes the material parameter of the electrode from single-crystalline silicon or polysilicon to metal or metal alloy, which fundamentally alters the electrical characteristics to eliminate depletion region formation while maintaining compatibility with existing semiconductor manufacturing processes
Solution Approach 2:
The patent employs metal or metal alloy materials for the electrode, representing a composite material approach that combines conductivity with stability properties superior to traditional semiconductor materials, thereby achieving both ease of manufacture and reliability
2Reliability
If MIM capacitor structure is used, then voltage coefficient of capacitance and temperature coefficient of capacitance are reduced, but capacitance density is limited as device dimensions shrink
Solution Approach 1:
The patent transitions from planar capacitor geometry to a three-dimensional structure where the electrode extends along the sidewall of the insulating layer, utilizing vertical space to increase capacitance density without expanding the horizontal footprint
Solution Approach 2:
The electrode is positioned to surround and encapsulate the insulating layer, creating a nested configuration where the conductor wraps around the dielectric, maximizing the interfacial area for capacitance while maintaining a compact overall structure
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 design stabilizes capacitance and significantly increases capacitance density, potentially up to 40 to 60 fF/um2, while improving plug landing flexibility and conductivity between electrodes, addressing the limitations of existing capacitors in integrated circuits.
Implementation Method 1
an intermediate dielectric layer located between the inner electrode and the outer electrode and surrounding the inner electrode, such that the inner electrode is electrically isolated from the outer electrode
Implementation Method 2
conductor-insulator-conductor capacitor with a higher capacitance density
Data Source
AI summary
A conductor-insulator-conductor capacitor and a method of fabricating the same are provided. The conductor-insulator-conductor capacitor includes first to third conductive layers and first and second insulating layers. The first insulating layer is located on the first conductive layer and covers the first conductive layer. The second conductive layer is located on the first insulating layer and covers at least a portion of the first insulating layer. The second insulating layer is located on the second conductive layer and covers the top surface and the sidewall of the second conductive layer. The second conductive layer is surrounded and encapsulated by the first insulating layer and the second insulating layer. The third conductive layer is located on the second insulating layer and covers the sidewalls of the second insulating layer and the first conductive layer. The third conductive layer is in physical contact with and electrically connected to the first conductive layer.