MIM Capacitor Bottom Electrode Extension for High Density
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Solution Overview
Problem
MIM capacitors face a challenge in maximizing capacitance values while minimizing surface area, which is essential for high packing density in semiconductor devices, as capacitance generally decreases with reduced surface area, and existing structures like crown capacitors do not fully satisfy this requirement.
Innovation Solution
The design involves forming MIM capacitors with extended bottom electrodes to increase surface area by extending them to the polysilicon layer or through a portion of the STI, allowing for increased capacitance without adverse effects on other device regions, and integrating these capacitors within the existing process flow for semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the bottom electrode is extended to increase surface area, then the capacitance value is improved, but the device complexity increases
Solution Approach 1:
The extended bottom electrode serves multiple functions: it provides the lower electrode for the MIM capacitor, establishes electrical contact through the conductive layer, and interfaces with the STI region for proper device integration. This multi-functionality reduces the need for separate structures and simplifies the overall device architecture despite the extended geometry
Solution Approach 2:
The capacitor bottom electrode is merged with the existing conductive layer and STI contact structure. By extending the bottom electrode through the conductive layer to contact the STI, the design combines multiple structural elements into a unified configuration, reducing the number of discrete components and simplifying fabrication processes
Data Source
AI summary
The present disclosure provides a semiconductor device that includes a semiconductor substrate, an isolation structure formed in the semiconductor substrate, a conductive layer formed over the isolation structure, and a metal-insulator-metal (MIM) capacitor formed over the isolation structure. The MIM capacitor has a crown shape that includes a top electrode, a first bottom electrode, and a dielectric disposed between the top electrode and the first bottom electrode, the first bottom electrode extending at least to a top surface of the conductive layer.