3D Memory Dummy Channel Isolation via Insulating Film
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Solution Overview
Problem
Current three-dimensional memory devices face challenges in effectively isolating dummy vertical channels from the substrate, leading to potential electrical leakage and reduced memory efficiency.
Innovation Solution
The implementation of a three-dimensional memory device structure that includes alternating stacks of insulating and conductive layers with memory opening fill structures and dummy memory opening fill structures, where the dummy memory film electrically isolates the dummy vertical channel from the substrate, preventing electrical contact and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy vertical channels are formed in three-dimensional memory devices, then memory device structure is completed, but electrical leakage occurs due to insufficient isolation from substrate
Solution Approach 1:
An insulating layer is introduced as an intermediary between the dummy vertical channel and the substrate. This insulating layer acts as a mediator that prevents direct electrical contact, thereby eliminating electrical leakage while maintaining the structural integrity of the memory device.
Solution Approach 2:
The dummy vertical channel structure is segmented by introducing an insulating layer that divides the continuous conductive path. This segmentation breaks the electrical connection between the dummy channel and substrate, preventing harmful electrical leakage while preserving the memory device's functional channels.
2Ease of manufacture
If memory opening fill structures are formed with continuous memory film, then manufacturing process is simplified, but dummy channels cannot be electrically isolated
Solution Approach 1:
The memory film is treated differently in different locations: in functional memory openings, the memory film remains continuous for ease of manufacture, while in dummy memory openings, the memory film is removed or interrupted to enable electrical isolation. This local differentiation allows both manufacturing simplicity and electrical isolation reliability.
Solution Approach 2:
The continuous memory film is segmented selectively in dummy memory openings while remaining intact in functional openings. This segmentation approach maintains manufacturing simplicity for the majority of structures while enabling electrical isolation where needed, resolving the contradiction between ease of manufacture and reliability.
Data Source
AI summary
A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers, rows of memory openings vertically extending through the alternating stack, memory opening fill structures located within a first subset of the rows of memory openings, where each of the memory opening fill structures includes a respective memory film and a respective vertical semiconductor channel extending through an opening at a bottom portion of the respective memory film and contacting a respective underlying semiconductor material portion, and dummy memory opening fill structures located within a second subset of the rows of memory openings that do not belong the first subset, where each of the dummy memory opening fill structures includes a respective dummy memory film and a respective dummy vertical semiconductor channel that is electrically isolated from a respective underlying semiconductor material portion by a bottom portion of the respective dummy memory film.