Transition Metal Oxide Memory Device Using CVD for Oxygen Control
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Solution Overview
Problem
Conventional nonvolatile memory devices using resistance materials face challenges with high manufacturing costs, reduced productivity, and limited integration due to difficulties in etching resistors and controlling composition ratios, especially with thin-film structures and the MOCVD method, which limits oxygen content control and reset current reduction.
Innovation Solution
A nonvolatile memory device with a three-dimensional data storage layer formed of transition metal oxide, using a CVD method to control oxygen content and achieve a dense, uniform layer, reducing the size of the data storage layer while maintaining performance, and decreasing reset current requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PVD method is used to form thin-film resistor, then manufacturing process is simple, but layer quality is not dense and uniform and composition ratio control is difficult
Solution Approach 1:
The patent changes the deposition method from PVD to CVD, fundamentally altering the manufacturing parameter to achieve dense and uniform layer quality with controllable composition ratios. The CVD process allows precise control of metal and oxygen ratios by adjusting gas flow rates and deposition conditions.
Solution Approach 2:
The patent uses composite material structure with specific metal-to-oxygen ratios in the resistor layer, creating a composite oxide material that combines the benefits of density, uniformity, and compositional control that single-material PVD cannot achieve.
2Manufacturing precision
If MOCVD method is used to deposit metal oxide, then oxygen content can be controlled, but reset current reduction and high integration are limited due to thin-film shape
Solution Approach 1:
The patent transitions from two-dimensional thin-film structure to three-dimensional resistor structure by forming the resistor in a hole through etching. This dimensional change enables better integration scaling while maintaining oxygen content control through the CVD process.
3Reliability
If conventional DRAM process is used with resistance materials, then etching resistance is good, but etching takes long time and productivity is reduced
Solution Approach 1:
The patent applies local quality by providing etching protection only where needed - the organic coating is applied selectively to the resistor pattern areas that require protection during subsequent etching processes, rather than coating the entire wafer. This localized approach maintains etching resistance where required while minimizing process time.
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
The three-dimensional structure enhances integration and reduces reset current, improving data write and erase operations while maintaining storage performance, and allows for better control of oxygen content for optimal switching characteristics.
Implementation Method 1
A method of depositing metal oxide using an MOCVD method is disclosed in a Korean Patent Laid-Open Publication No. 2004-0055594. This publication discloses a technology of forming a metal-containing layer using a precursor.
Implementation Method 2
These materials can switch between a crystalline state and an amorphous state due to local heat generated by electric pulses. The phase-change layer changes between a crystalline state and an amorphous state depending on a degree of heat, resulting in a change of resistance.
Implementation Method 3
The resistor is used to heat the phase-change layer. The phase-change layer changes between a crystalline state and an amorphous state depending on a degree of heat
Data Source
AI summary
A nonvolatile memory device using a resistance material and a method of fabricating the same are provided. The nonvolatile memory device includes a switching element, and a data storage part electrically connected to the switching element. In the data storage part, a lower electrode is connected to the switching element, and an insulating layer is formed on the lower electrode to a predetermined thickness. The insulating layer has a contact hole exposing the lower electrode. A data storage layer is filled in the contact hole and the data storage layer is formed of transition metal oxide. An upper electrode is formed on the insulating layer and the data storage layer.