DRAM Capacitor Electrode Structure for Capacity and Stability
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Solution Overview
Problem
The challenge of maintaining sufficient capacitor storage capacity while ensuring stability becomes difficult with the high depth-to-width ratio in DRAM capacitors due to the miniaturization and high integration demands in semiconductor technologies.
Innovation Solution
A semiconductor structure is designed with a pillar-shaped conductive structure and a cup-shaped conductive structure forming a lower electrode, accompanied by a dielectric layer and an upper electrode, which enhances storage capacity and stability by reducing interference and maintaining a high depth-to-width ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the height of DRAM capacitor is increased to achieve high depth-to-width ratio for high integration, then the storage capacity per unit area is improved, but the stability of capacitor structure deteriorates
Solution Approach 1:
The lower electrode is segmented into two distinct parts: a pillar-shaped conductive structure at the bottom and a cup-shaped conductive structure at the top. This segmentation allows each part to fulfill specific functional requirements - the pillar provides structural support and vertical extension for high depth-to-width ratio, while the cup-shaped structure provides stability and supports the dielectric layer, thereby resolving the contradiction between height increase and structural stability.
Solution Approach 2:
The lower electrode employs an asymmetric design where the pillar-shaped conductive structure has a smaller cross-sectional area than the cup-shaped conductive structure. This asymmetric configuration creates a stable base (cup-shaped) that supports the taller pillar structure, enabling the capacitor to achieve high depth-to-width ratio while maintaining structural stability through the wider top portion.
2Area of stationary object
If miniaturization is pursued to reduce manufacturing process size, then integration density is improved, but the capacitor storage capacity deteriorates
Solution Approach 1:
The capacitor structure transitions from a planar two-dimensional layout to a three-dimensional vertical structure with high depth-to-width ratio. The pillar-shaped and cup-shaped conductive structures extend vertically, allowing the capacitor to achieve sufficient storage capacity within a reduced footprint area, thereby resolving the contradiction between miniaturization and storage capacity maintenance.
Data Source
AI summary
A preparation method for a semiconductor structure includes the following operations. A bit line structure, active pillars, and a word line structure are formed in turn on a substrate. Bottom ends of the active pillars are connected to the bit line structure, and the active pillars are connected with the word line structure. A pillar-shaped conductive structure is formed on the active pillars, and a cup-shaped conductive structure is formed on the pillar-shaped conductive structure. There is an electrode gap between the pillar-shaped conductive structure and the cup-shaped conductive structure, and the pillar-shaped conductive structure and the cup-shaped conductive structure form a lower electrode. A dielectric layer is formed on a surface of the lower electrode. An upper electrode is formed on a surface of the dielectric layer. The upper electrode fills the electrode gap.