Transition Metal Oxide Memory Cells with Excess Metal Content
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Solution Overview
Problem
Conventional non-volatile memory devices, such as flash memory and resistance random access memory (RAM) devices, face challenges in patterning complex materials like PrCaMnO3 layers, which affect integration density and uniformity, and require high voltages for switching characteristics.
Innovation Solution
The development of non-volatile memory cells with a transition metal oxide layer, represented by the chemical formula MxOy, where 'M' is a transition metal and 'x' and 'y' represent the composition, with excessive transition metal content to improve switching characteristics, using techniques like oxygen plasma treatment, sputtering, and chemical vapor deposition to form the metal oxide layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PCMO layer is used as the data storage material layer, then the switching characteristics can be achieved, but it is difficult to pattern the layer using conventional photolithography/etch process
Solution Approach 1:
The patent changes the material composition parameters by using a transition metal oxide layer with excessive transition metal content (non-stoichiometric composition where x > y in MxOy) instead of stoichiometric PCMO. This parameter change enables the material to be patterned using conventional photolithography and etch processes while maintaining switching characteristics, resolving the contradiction between reliability and ease of manufacture.
2Reliability
If four kinds of materials are mixed to form the PCMO layer, then the data storage function can be achieved, but it is difficult to form the layer having a uniform composition throughout the semiconductor substrate
Solution Approach 1:
The patent uses a composite material approach by forming a transition metal oxide layer with excessive transition metal content that can be deposited as a single layer rather than mixing four different materials. This simplifies the deposition process and achieves uniform composition throughout the substrate while maintaining the data storage function, resolving the contradiction between reliability and manufacturing precision.
3Device complexity
If a ZnO-based data storage material layer is used, then the structure can be simplified, but the switching characteristic occurs at a high voltage of about 50 V
Solution Approach 1:
The patent changes the compositional parameter by using a transition metal oxide layer with excessive transition metal content (non-stoichiometric composition) instead of stoichiometric ZnO. This parameter change reduces the switching voltage from about 50 V to lower operating voltages while maintaining the simplified structure, resolving the contradiction between device complexity and energy consumption.
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 enhances the switching characteristics and reduces operation voltages of non-volatile memory cells, improving integration density and uniformity, and facilitates the realization of high-performance resistance RAM devices.
Implementation Method 1
The variable resistive material layer, that is, a data storage material layer, may be changed into a conductor or an insulator according to a polarity and/or a magnitude of an electrical signal (voltage or current) applied to the electrodes
Implementation Method 2
using techniques like oxygen plasma treatment, sputtering, and chemical vapor deposition to form the metal oxide layer
Implementation Method 3
using techniques like oxygen plasma treatment, sputtering, and chemical vapor deposition to form the metal oxide layer
Implementation Method 4
using techniques like oxygen plasma treatment, sputtering, and chemical vapor deposition to form the metal oxide layer
Data Source
AI summary
Non-volatile memory cells employing a transition metal oxide layer as a data storage material layer are provided. The non-volatile memory cells include a lower and upper electrodes overlapped with each other. A transition metal oxide layer pattern is provided between the lower and upper electrodes. The transition metal oxide layer pattern is represented by a chemical formula MxOy. In the chemical formula, the characters “M”, “O”, “x” and “y” indicate transition metal, oxygen, a transitional metal composition and an oxygen composition, respectively. The transition metal oxide layer pattern has excessive transition metal content in comparison to a stabilized transition metal oxide layer pattern. Methods of fabricating the non-volatile memory cells are also provided.