Variable Resistance Layer Oxygen Deficiency Breakdown Voltage
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Solution Overview
Problem
Nonvolatile memory devices with variable resistance elements require high initial breakdown voltages due to the high film density of tantalum oxide layers formed through oxygen plasma processes, leading to reliability concerns when formed using other methods like sputtering, which have more defects and lower initial breakdown voltages but decreased reliability.
Innovation Solution
A nonvolatile memory device with a variable resistance layer comprising a first oxygen-deficient metal oxide and a second metal oxide with a non-metal element, such as carbon, having a lower film density than stoichiometric composition, allowing for a lower initial breakdown voltage and maintaining reliability by increasing defects as a conductive path starting point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxygen plasma process is used to form the second tantalum oxide layer, then film density and precision are improved, but initial breakdown voltage becomes excessively high
Solution Approach 1:
The patent changes the oxygen content parameter of the metal oxide layer by controlling the oxygen plasma treatment conditions (oxygen flow rate, treatment time, power) to achieve the optimal balance between film density and initial breakdown voltage. Specifically, the oxygen content atomic percentage is controlled within 40-70% range to prevent excessive density while ensuring sufficient precision.
Solution Approach 2:
The patent introduces a dynamic control mechanism where the oxygen plasma treatment parameters are adjusted based on the desired performance characteristics. The process allows dynamic optimization of the trade-off between film density (precision) and initial breakdown voltage by varying treatment conditions according to specific application requirements.
2Ease of operation
If sputtering method is used to form the metal oxide layer, then initial breakdown voltage is reduced, but film defects increase and reliability decreases
Solution Approach 1:
The patent uses oxygen plasma treatment as an intermediary process between film formation and device operation. This intermediary step repairs defects in the sputtered film by introducing oxygen atoms that fill vacancies and reduce oxygen deficiencies, thereby improving film reliability without significantly increasing the initial breakdown voltage.
Solution Approach 2:
The patent employs oxygen plasma (a strong oxidizing environment) to accelerate the oxidation process in the metal oxide layer. This accelerated oxidation fills oxygen vacancies and reduces defects, thereby improving film reliability while maintaining controlled initial breakdown voltage characteristics.
3Manufacturing precision
If high oxygen content atomic percentage is achieved in the second tantalum oxide layer, then film precision is improved, but initial breakdown voltage increases
Solution Approach 1:
The patent optimizes the oxygen content atomic percentage parameter within a specific range (40-70%) to achieve the best balance between film precision and initial breakdown voltage. This parameter optimization ensures sufficient film precision for reliable operation while preventing excessively high initial breakdown voltage that would complicate device operation.
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 approach reduces the initial breakdown voltage while preventing reliability decreases by incorporating a non-metal element like carbon into the second variable resistance layer, achieving a lower film density and facilitating a conductive path at lower voltages without compromising device stability.
Implementation Method 1
In the oxygen plasma process, oxygen ions and the like are driven in from the film surface, and oxygen is dispersed in defects and between atoms.
Implementation Method 2
oxygen ions and the like are driven in from the film surface
Data Source
AI summary
A variable resistance layer includes a first variable resistance layer comprising a first metal oxide that is oxygen deficient and a second variable resistance layer comprising a second metal oxide having a degree of oxygen deficiency that is different from that of the first metal oxide, wherein the second variable resistance layer includes a non-metal element A that is different from oxygen, x<(y+z) is satisfied where a composition of the first variable resistance layer is represented by MOx and a composition of the second variable resistance layer is represented by NOyAz, the second variable resistance layer has a higher resistivity than a resistivity of the first variable resistance layer, and a film density of the second variable resistance layer is lower than a theoretical film density of the second metal oxide which has a stoichiometric composition.