MIM Capacitor With Extended Plate For High Capacitance
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Solution Overview
Problem
In integrated circuit devices, the miniaturization of semiconductor chips makes it challenging to design capacitors with sufficient capacitance due to limited insulator and electrode contact area, necessitating an increase in capacitance while minimizing the horizontal footprint.
Innovation Solution
A metal insulator metal (MIM) capacitor design featuring a bottom capacitor plate with an extended, curved top face within a trench, covered by a high-k dielectric layer and a top capacitor plate, which increases the capacitor plate area and thus capacitance without expanding the footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor uses conventional flat parallel metal plates, then the manufacturing process is simple, but the capacitance is insufficient due to limited contact area in miniaturized structures
Solution Approach 1:
The bottom capacitor plate is formed with a three-dimensional extended top face structure that protrudes upward from the trench bottom, transforming the conventional two-dimensional flat plate into a multi-dimensional structure. This vertical extension increases the effective contact area between capacitor plates without expanding the horizontal footprint, thereby increasing capacitance while maintaining compact dimensions suitable for miniaturized integrated circuits
Solution Approach 2:
The extended top face structure is nested within the trench feature, with the high-k dielectric layer conformally coating the extended surface and the top capacitor plate positioned above it. This nested arrangement allows the additional capacitance-generating surface area to be integrated within the existing trench boundaries rather than requiring additional horizontal space
2Reliability
If the capacitor plate area is increased to improve capacitance, then the capacitance increases, but the horizontal footprint area expands
Solution Approach 1:
Instead of increasing capacitor plate area in the horizontal plane, the invention extends the bottom capacitor plate vertically upward to create an extended top face. This dimensional transition from horizontal to vertical expansion increases the effective contact area for capacitance while keeping the horizontal footprint constant, effectively decoupling capacitance increase from footprint expansion
Solution Approach 2:
The extension of the bottom capacitor plate is localized to the central region of the trench, creating a non-uniform three-dimensional structure where the top face area is greater than the bottom face area. This localized quality change concentrates the capacitance-enhancing geometry where it is most effective while maintaining compact overall dimensions
Data Source
AI summary
A capacitor structure and a method for constructing the structure are described. A metal insulator metal capacitor in an integrated circuit device includes a first dielectric layer on a substrate. The first dielectric layer has a linear trench feature in which the capacitor is disposed. A bottom capacitor plate is in a lower portion of the trench. The bottom capacitor plate has an extended top face so that the extended top face extends upwards in a central region of the bottom capacitor plate metal relative to side regions. A high-k dielectric layer is disposed over the extended top face of the bottom capacitor plate. A top capacitor plate is disposed in a top, remainder portion of the trench on top of the high-k dielectric layer.