Angled Semiconductive Pillar for DRAM Contact Isolation
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Solution Overview
Problem
The challenge in semiconductor device design is to increase integration density and performance while preventing inadvertent shorting between components, particularly in DRAM devices, as feature dimensions shrink and packing density increases, leading to electrical shorts between digit line and storage node contacts.
Innovation Solution
The formation of semiconductive pillar structures with angled end portions relative to the central portion, which increases the distance between storage node and bit line contacts, reduces the likelihood of shorting and enhances mechanical stability, and allows for increased active areas for contacts, thereby minimizing capacitive coupling and overlap with word lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature dimensions are reduced and packing density is increased to improve integration density, then the number of memory cells per unit area increases, but the likelihood of inadvertent shorting between digit line contacts and storage node contacts increases
Solution Approach 1:
The pillar structure employs asymmetric geometry where the end portions are oriented at an angle (e.g., 45 degrees) relative to the central portion. This asymmetric configuration increases the lateral distance between digit line contacts and storage node contacts, reducing the probability of inadvertent shorting while maintaining compact vertical integration for high density
Solution Approach 2:
The invention transitions from planar contact arrangement to three-dimensional pillar structures with angled end portions. By utilizing vertical stacking and angular orientation in the third dimension, the design achieves both high integration density and increased contact separation to prevent shorting
2Reliability
If contact spacing is increased to prevent shorting, then reliability improves, but the active area available for contacts decreases
Solution Approach 1:
The pillar structure utilizes vertical extension and angular orientation to increase contact separation distance without reducing the lateral active area of contacts. The angled end portions provide both separation for reliability and sufficient contact area for electrical performance
3Reliability
If pillar structures with angled end portions are formed to increase contact distance and prevent shorting, then reliability improves, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The pillar structure is segmented into distinct portions: a central portion and angled end portions. This segmentation allows each portion to be optimized independently for its function while simplifying the overall manufacturing process through modular formation steps
Solution Approach 2:
Different portions of the pillar structure have different orientations and properties: the central portion provides structural support while the angled end portions provide contact separation. This local differentiation optimizes each region for its specific function, achieving reliability without excessive overall complexity
Data Source
AI summary
A microelectronic device comprises a semiconductive pillar structure comprising a central portion, a first end portion, and a second end portion on a side of the central portion opposite the first end portion, the first end portion oriented at an angle with respect to the central portion and extending substantially parallel to the second end portion, a digit line contact on the central portion of the semiconductive pillar structure, a first storage node contact on the first end portion, and a second storage node contact on the second end portion. Related microelectronic devices, electronic systems, and methods are also described.