C-Shaped Deep Trench Capacitor for High-Density Memory
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Solution Overview
Problem
Conventional deep trench capacitors face challenges in increasing capacitance due to insufficient surface areas for storing electric charges, particularly during the etching process, where edge length surface areas are not sufficient as memory units shrink.
Innovation Solution
A memory device with C-shaped deep trench capacitors is developed, where both the outer and inner edges of the C-shaped profile provide additional surface areas for capacitance, and a method involving specific etching and doping processes forms the capacitors to enhance capacitance without requiring high-resolution lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If memory units are shrunk to increase density and speed, then device size is reduced and integration is improved, but the electrode plate surface area becomes insufficient for storing electric charges
Solution Approach 1:
The invention transitions from a conventional planar electrode plate to a three-dimensional C-shaped deep trench capacitor structure. By etching deep trenches into the substrate and forming capacitors along the trench walls, the electrode surface area is extended into the vertical dimension, achieving sufficient capacitance storage capacity while maintaining a compact footprint for high-density memory integration
Solution Approach 2:
The C-shaped capacitor structure is formed by nesting multiple functional layers within a deep trench. The trench itself is etched into the substrate, and subsequent layers are deposited and patterned to create the C-shaped configuration, effectively nesting the capacitor structure within the available space to maximize surface area utilization
2Ease of manufacture
If conventional oval-shaped deep trench capacitors are used, then fabrication is simpler, but the edge length surface area is insufficient for adequate capacitance
Solution Approach 1:
The invention employs a C-shaped (asymmetric) capacitor structure instead of a conventional oval shape. The C-shape provides both an outer edge and an inner edge, effectively doubling the available surface area for capacitance compared to a simple oval contour, while still being manufacturable using standard lithography and etching processes
Solution Approach 2:
The capacitor structure is segmented into multiple functional regions: the deep trench portion, the C-shaped electrode, and the surrounding dielectric layers. This segmentation allows each component to be optimized independently for its specific function while contributing to the overall capacitance performance
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
The C-shaped deep trench capacitors increase capacitance by utilizing both edge and inner surface areas, reducing the size of unit cells and improving device integrity while maintaining lower resistance, thus addressing the limitations of conventional oval-shaped capacitors.
Implementation Method 1
fabrication of oval-shaped deep trench capacitors 102 encounter challenges during the etching process
Implementation Method 2
a method involving specific etching and doping processes forms the capacitors
Data Source
AI summary
The invention is related to a memory device, including a substrate, a capacitor which is substantially C-shaped in a cross section parallel to the substrate surface and a word line coupling the capacitor. In an embodiment, the C-shaped capacitor is a deep trench capacitor, and in alternative embodiment, the C-shaped capacitor is a stack capacitor. Both inner edge and outer edge of the C-shaped capacitor can be used for providing capacitance.