Cylindrical DRAM Capacitor with Protruding Inner Electrode
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Solution Overview
Problem
Conventional DRAM devices face challenges in achieving high capacitance density due to limitations in increasing the surface area of capacitors, which affects refresh performance.
Innovation Solution
A semiconductor device with a capacitor featuring a cylindrical bottom electrode having protruding portions on its inner surface and concaved portions on its outer surface, with a conformally deposited dielectric layer and top electrode, significantly increasing the surface area and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional capacitor structures are used, then the device complexity is low, but the capacitance density is insufficient
Solution Approach 1:
The invention transitions from a conventional planar capacitor structure to a three-dimensional cylindrical structure with protruding portions on the inner surface and concaved portions on the outer surface. This dimensional change allows the capacitor to utilize vertical space and surface area more effectively, significantly increasing the electrode surface area and thus the capacitance density without proportionally increasing device footprint.
Solution Approach 2:
The cylindrical electrode is segmented into multiple protruding portions on the inner surface and concaved portions on the outer surface. This segmentation creates additional surface area for charge storage, allowing the capacitor to achieve higher capacitance density by dividing the electrode into functional segments that maximize the effective charging area.
2Quantity of substance
If the surface area of the capacitor is increased, then the capacitance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The supporting structure is formed in advance before the capacitor electrodes are created. This pre-formed supporting structure serves as a template that guides the subsequent formation of the cylindrical electrode with its protruding and concaved portions. By establishing the geometric framework beforehand, the invention simplifies the control of surface area and reduces manufacturing precision requirements during the electrode formation process.
Solution Approach 2:
The supporting structure acts as an intermediary element between the substrate and the capacitor electrodes. It mediates the complex geometry formation by providing a pre-defined scaffold that determines the shape and surface area of the cylindrical electrode, thereby simplifying the manufacturing process and reducing the precision requirements for direct electrode patterning.
3Reliability
If a conformal dielectric layer is deposited on the cylindrical electrode, then the capacitor reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention uses a cylindrical (curved) electrode structure instead of a planar geometry. This curvature enables conformal deposition of the dielectric layer to uniformly cover the entire electrode surface, including the protruding and concaved portions. The conformal coverage ensures consistent dielectric thickness and reliable capacitor performance, while the cylindrical geometry is compatible with standard conformal deposition techniques used in semiconductor manufacturing.
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 enhanced surface area of the capacitor leads to improved capacitance and refresh performance in DRAM devices, addressing the limitations of conventional designs.
Implementation Method 1
The dielectric layer is conformally disposed on the inner surface and the outer surface of the cylindrical bottom electrode, and covering the plurality of protruding portions and the plurality of concaved portions of the cylindrical bottom electrode
Implementation Method 2
The top electrode is conformally disposed on the dielectric layer over the inner surface and the outer surface of the cylindrical bottom electrode
Data Source
AI summary
A semiconductor device includes a landing pad and a capacitor disposed on and electrically connected to the landing pad. The capacitor includes a cylindrical bottom electrode, a dielectric layer and a top electrode. The cylindrical bottom electrode is disposed on an in contact with the landing pads, wherein an inner surface the cylindrical bottom electrode includes a plurality of protruding portions, and an outer surface of the cylindrical bottom electrode includes a plurality of concaved portions. The dielectric layer is conformally disposed on the inner surface and the outer surface of the cylindrical bottom electrode, and covering the protruding portions and the concaved portions. The top electrode is conformally disposed on the dielectric layer over the inner surface and the outer surface of the cylindrical bottom electrode.