Cross-Point Memory Sidewall Protection via Dielectric Coating
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Solution Overview
Problem
The fabrication of cross-point memory arrays often results in undesirable effects such as damage and contamination of sidewalls during etching, leading to unintended changes in device characteristics and reduced yield.
Innovation Solution
A method involving the formation of protective dielectric materials on sidewalls of memory stack structures to protect vulnerable elements, with selective exposure and cleaning processes to prevent contamination and damage during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching is performed to form stacked structures, then memory elements are patterned, but sidewalls are damaged and contaminated
Solution Approach 1:
A protective coating is deposited on the sidewalls of the stacked structure before the etching process. This preliminary protective action prevents the sidewalls from damage and contamination during etching, while still allowing the etching to proceed to form the required stacked structures with proper patterning.
Solution Approach 2:
The protective coating acts as an intermediary layer between the etching process and the sidewalls of the stacked structure. It mediates the harmful interaction by being exposed to the etching environment while protecting the underlying sidewall materials from damage and contamination.
2Object-affected harmful factors
If sidewalls are protected during etching, then contamination is minimized, but additional fabrication steps are required
Solution Approach 1:
The protective coating is deposited as a preliminary step before etching. This single additional step prevents sidewall contamination and damage, and the coating can be removed in a subsequent step, making the overall process addition minimal while achieving the protection goal.
Solution Approach 2:
The protective coating serves multiple functions: it protects sidewalls from etching damage, prevents contamination during the etching process, and can be designed to facilitate subsequent processing steps. This multi-functionality reduces the need for additional specialized protection steps.
Data Source
AI summary
The disclosed technology relates generally to integrated circuit devices, and in particular to cross-point memory arrays and methods for fabricating the same. In one aspect, a memory device of the memory array comprises a substrate and a memory cell stack formed between and electrically connected to first and second conductive lines. The memory cell stack comprises a first memory element over the substrate and a second memory element formed over the first element, wherein one of the first and second memory elements comprises a storage element and the other of the first and second memory elements comprises a selector element. The memory cell stack additionally comprises a first pair of sidewalls opposing each other and a second pair of sidewalls opposing each other and intersecting the first pair of sidewalls. The memory device additionally comprises first protective dielectric insulating materials formed on a lower portion of the first pair of sidewalls and an isolation dielectric formed on the first protective dielectric insulating material and further formed on an upper portion of the first pair of sidewalls.