Stacked Capacitor Electrode Structure for Memory Cell
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Solution Overview
Problem
As semiconductor devices miniaturize, the reduced area for capacitors in memory cells leads to insufficient capacitance and mechanical strength issues, causing electrode collapse and increased contact resistance, which degrades capacitor performance.
Innovation Solution
The semiconductor device incorporates a stacked capacitor structure with a crown-shaped first lower electrode and a cylindrical second lower electrode, where the second electrode covers the inner and outer surfaces of the first electrode, increasing contact area and mechanical support through additional supporters, enhancing capacitance and preventing electrode collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the area of the capacitor is reduced to achieve miniaturization, then the semiconductor device size is reduced, but the capacitance becomes insufficient
Solution Approach 1:
The invention transitions from a planar capacitor structure to a three-dimensional stacked structure with multiple lower electrodes (first lower electrode 30 and second lower electrode 40a) arranged vertically. This dimensional change allows the capacitor to achieve sufficient capacitance within a reduced planar area by utilizing vertical space, thereby resolving the contradiction between miniaturization and capacitance maintenance.
Solution Approach 2:
The patent implements a nested configuration where the second lower electrode 40a is positioned on top of the first lower electrode 30, with both electrodes extending into the same vertical space. This nesting arrangement maximizes the use of available volume, allowing multiple electrode structures to coexist in a compact footprint while maintaining high capacitance.
2Quantity of substance
If the aspect ratio of the capacitor increases to achieve sufficient capacitance in reduced area, then the capacitance is improved, but the mechanical strength of the lower electrode decreases causing collapse
Solution Approach 1:
The lower electrode structure is segmented into multiple discrete components: the first lower electrode 30 and the second lower electrode 40a. This segmentation allows each electrode to be independently supported by inter-layer insulating films (first inter-layer insulating film 14 and second inter-layer insulating film 15), distributing the mechanical load and preventing collapse even with increased aspect ratio.
Solution Approach 2:
The inter-layer insulating films 14 and 15 serve as intermediary support structures between the lower electrodes and the upper electrode. These films provide mechanical reinforcement to the high aspect ratio lower electrodes, preventing collapse while allowing the electrodes to maintain their extended vertical structure for high capacitance.
3Area of moving object
If the area for capacitor formation is reduced, then the device is miniaturized, but the contact area between stacked lower electrodes decreases increasing contact resistance
Solution Approach 1:
The contact interface between the first lower electrode 30 and second lower electrode 40a is extended from a simple planar contact to a multi-dimensional interface that includes the inner surface of the first lower electrode and the outer surface of the second lower electrode. This dimensional extension of the contact area maintains low contact resistance even when the overall planar footprint is reduced.
Data Source
AI summary
A semiconductor device may include, but is not limited to a first electrode upwardly extending, and a second electrode upwardly extending along the first electrode. The first electrode includes a lower portion and an upper portion. The second electrode covers a bottom surface and an outer side surface of the lower portion of the first electrode. The upper portion of the first electrode is positioned higher than the second electrode.