Selective Deposition of Nickel Oxide Memory Cells
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Solution Overview
Problem
Fabricating memory devices from rewriteable resistivity-switching materials is difficult due to their challenging chemical etching, which increases costs and complexity in integrated circuit fabrication.
Innovation Solution
A selective deposition process is used to form reversible resistance-switching elements without etching, employing materials like nickel oxide or nickel, which are then oxidized to simplify the fabrication of memory cells and eliminate the need for etching these materials.
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 difficult chemical etching
Solution Approach 1:
The patent extracts the etching step from the fabrication process by using selectively deposited materials (nickel, nickel oxide, nickel nitride) that do not require chemical etching. The selective deposition allows the resistivity-switching material to be formed directly in the desired pattern without subsequent removal steps, eliminating the harmful etching process while maintaining memory functionality.
Solution Approach 2:
The patent changes the material parameters by selecting specific materials (nickel, nickel oxide, nickel nitride) with particular properties - namely their ability to be selectively deposited and their inherent resistivity-switching characteristics. This parameter change allows the material to serve dual purposes: forming the memory element and eliminating the need for etching.
2Reliability
If difficult-to-etch materials like nickel oxide are used, then material performance for resistance switching is achieved, but manufacturing costs and process complexity increase
Solution Approach 1:
The patent introduces selectively deposited nickel, nickel oxide, or nickel nitride layers as intermediary materials that facilitate the formation of the resistivity-switching element without requiring harsh etching processes. These materials act as mediators between the deposition process and the final memory structure, enabling easy manufacturing while maintaining performance.
Solution Approach 2:
The patent replaces the chemical etching system with a selective deposition system. Instead of using chemical reactions to remove material, the invention uses controlled deposition processes to form the resistivity-switching material directly in the desired configuration, substituting a more manageable mechanical/physical process for a difficult chemical one.
3Device complexity
If selective deposition is used to form reversible resistance-switching elements, then etching steps are eliminated, but deposition process control requirements increase
Solution Approach 1:
The patent applies universal deposition techniques that can form multiple functional layers (nickel, nickel oxide, nickel nitride) with a single process approach. The selective deposition method serves multiple functions: pattern definition, material formation, and etch replacement, reducing the need for separate precision-controlled steps while achieving the desired structural complexity.
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 nickel and nickel oxide layers, reducing fabrication complexity and costs, while enabling the use of difficult-to-etch materials in memory devices.
Implementation Method 1
a nickel-containing layer may be used in a reversible resistance-switching element of a memory cell without the nickel oxide layer being etched. For example, a reversible resistance-switching element may be formed by employing a deposition process such as electroplating, electroless deposition, or the like, to selectively deposit a nickel-containing layer only on conductive surfaces formed above a substrate
Implementation Method 2
Nickel-containing films such as Ni, Ni x Py, NiO, NiO x , NiO x P y , etc., are difficult to etch chemically. In at least one embodiment, through use of a selective deposition process, a nickel oxide layer may be used in a reversible resistance-switching element of a memory cell without the nickel oxide layer being etched
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
In some aspects, a method of forming a memory cell is provided that includes forming a first conductor above a substrate; forming a diode above the first conductor; forming a reversible resistance-switching element above the first conductor using a selective deposition process; and forming a second conductor above the diode and the reversible resistance-switching element. Numerous other aspects are provided.