Vertical Trench Capacitor Structure for Higher Memory Density
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Solution Overview
Problem
Planar memory cells face challenges in scaling to smaller sizes due to limitations in process technology and fabrication techniques, leading to an upper limit in memory density.
Innovation Solution
The development of semiconductor devices with transistors and capacitors featuring a dielectric layer with step-shaped shifts and electrodes of varying diameters, arranged in a grid array, which allows for improved capacitors with enhanced mechanical stability and reduced fabrication complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If planar process and fabrication techniques are used to scale memory cells to smaller sizes, then memory density can be improved, but process complexity and fabrication costs increase significantly
Solution Approach 1:
The patent transitions from planar 2D capacitor structures to three-dimensional trench capacitor structures. The capacitor is formed vertically within a trench extending into the substrate, utilizing the third dimension (depth) to increase storage capacity without expanding the planar footprint. This dimensional change enables continued scaling and density improvement while avoiding the prohibitive complexity of advanced planar processes.
2Quantity of substance
If planar process techniques are used to scale memory cells, then fabrication costs can be controlled, but memory density approaches an upper limit
Solution Approach 1:
By forming capacitors vertically in trenches rather than laterally in planar structures, the patent achieves higher memory density using manufacturing processes that remain cost-effective. The trench capacitor structure leverages vertical space utilization, allowing continued scaling without requiring prohibitively expensive advanced planar fabrication techniques.
3Stability of the object's composition
If conventional capacitor structures are used, then fabrication is simpler, but mechanical stability and space utilization are reduced
Solution Approach 1:
The capacitor structure is segmented into distinct functional components: a trench region extending vertically into the substrate, a first electrode positioned within the trench, a dielectric layer surrounding the electrode, and a second electrode completing the capacitor structure. This segmentation provides mechanical stability through well-defined geometric boundaries while optimizing space utilization through vertical arrangement.
Solution Approach 2:
The dielectric layer is laterally positioned to surround the first electrode, with the second electrode surrounding the dielectric layer, creating a nested configuration. This nested structure maximizes space utilization within the trench volume while providing mechanical stability through concentric geometric boundaries that distribute stress evenly.
Data Source
AI summary
A semiconductor device and method for forming thereof are provided. The semiconductor device includes transistors and capacitors coupled with the transistors, respectively. Each capacitor includes a first electrode extending along a vertical direction and coupled with a corresponding transistor, a dielectric layer laterally surrounding the first electrode, and a second electrode laterally surrounding the dielectric layer. The dielectric layer includes at least one step-shaped shift along the vertical direction and a diameter difference between a first diameter of the dielectric layer at a first side of the step-shaped shift and a second diameter of the dielectric layer at a second side of the step-shaped shift.