Selective Deposition of Nickel Oxide Memory Cells
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Solution Overview
Problem
Fabricating memory devices from rewriteable resistivity-switching materials is challenging due to their difficulty in chemical etching, increasing fabrication costs and complexity.
Innovation Solution
A selective deposition process is used to form reversible resistance-switching elements without etching, employing materials like nickel oxide, which can be deposited and oxidized to create a reversible resistivity-switching material, simplifying the fabrication of memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rewriteable resistivity-switching materials are used in memory devices, then memory functionality is achieved, but fabrication complexity and costs increase due to difficulty in chemical etching
Solution Approach 1:
The patent extracts the etching step from the fabrication process by using a selective deposition approach. The nickel oxide layer is deposited selectively on the diode structure, eliminating the need for subsequent etching operations. This removes the problematic chemical etching step that caused fabrication complexity while maintaining the memory functionality of the resistivity-switching material.
Solution Approach 2:
Instead of the conventional approach of depositing a layer and then etching it to form the resistance-switching element, the patent inverts the process by selectively depositing the material only where needed. This reverse approach eliminates etching entirely and simplifies the fabrication process while achieving the same functional result.
2Reliability
If nickel oxide layers are deposited and etched to form reversible resistance-switching elements, then memory cell functionality is achieved, but fabrication costs increase
Solution Approach 1:
The patent removes the etching step from the fabrication sequence, extracting the problematic chemical processing operation. By using selective deposition, the nickel oxide layer is formed directly in the desired pattern without requiring costly etching chemicals, equipment usage, and associated waste treatment processes.
Solution Approach 2:
The patent employs a deposition process that uses inexpensive precursor materials and avoids costly etching chemicals. The selective deposition method allows for cost-effective formation of the resistance-switching layer by depositing material only where required, reducing material waste and processing costs.
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
This approach simplifies the fabrication of memory cells by eliminating the need for etching of nickel and nickel oxide layers, reducing complexity and costs, while enabling the use of difficult-to-etch materials like nickel oxide in memory devices.
Implementation Method 1
A selective deposition process is used to form reversible resistance-switching elements without etching, employing materials like nickel oxide, which can be deposited and oxidized to create a reversible resistivity-switching material
Implementation Method 2
nickel oxide, which can be deposited and oxidized to create a reversible resistivity-switching material
Implementation Method 3
rewriteable non-volatile memory cell that includes a diode coupled in series with a reversible resistivity-switching material
Data Source
AI summary
In some aspects, a method of forming a memory cell is provided that includes (1) forming a first conductor above a substrate; (2) forming a diode above the first conductor; (3) forming a reversible resistance-switching element above the first conductor using a selective deposition process; and (4) forming a second conductor above the diode and the reversible resistance-switching element. Numerous other aspects are provided.