Niobium Oxide Memory Layer Crystal Orientation
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Solution Overview
Problem
The manufacturing of resistance change elements and nonvolatile memory devices is complicated by the need for forming processing to reduce the resistance of the memory layer from a high to a low resistance state, which is time-consuming and challenging.
Innovation Solution
A resistance change element is developed with a memory layer made of niobium oxide (NbOx) between two conductive layers, where the memory layer can reversibly transition between low and high resistance states due to voltage and current, eliminating the need for forming processing by orienting crystal planes such as (100), (010), or (110) in the stacking direction, and maintaining a specific intensity ratio in X-ray photoelectron spectroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If forming processing is performed to reduce resistance of the memory layer, then the resistance change element can be set to a usage state, but the manufacturing process becomes complicated and time-consuming
Solution Approach 1:
The patent applies preliminary action by pre-orienting the crystal planes of the niobium oxide memory layer during the deposition process itself, rather than requiring subsequent forming processing. The memory layer is deposited with specific crystal plane orientations ((100), (010), or (110)) that inherently provide low resistance states, eliminating the need for post-manufacturing forming steps.
Solution Approach 2:
The patent changes the physical and chemical parameters of the memory layer by controlling the crystal structure and orientation of niobium oxide during deposition. By adjusting deposition conditions to achieve specific crystal plane orientations, the resistance characteristics are fundamentally altered from high resistance (requiring forming) to low resistance (ready for use), resolving the contradiction between reliability and manufacturing complexity.
2Reliability
If forming processing is performed to reduce resistance, then the memory layer transitions to low resistance state, but the manufacturing time increases
Solution Approach 1:
The low resistance state is achieved through preliminary action embedded in the deposition process. The niobium oxide layer is deposited with controlled crystal plane orientations that inherently create conductive pathways, providing low resistance from the outset without requiring time-consuming forming processing steps afterward.
Solution Approach 2:
The patent extracts the forming processing step from the manufacturing sequence by incorporating the resistance-reducing crystal orientation directly into the deposition process. This removes the separate, time-consuming forming operation while maintaining the desired low resistance initial state.
3Ease of manufacture
If the memory layer is deposited without specific crystal orientation, then deposition is simpler, but forming processing is required which complicates manufacturing
Solution Approach 1:
The patent modifies the deposition parameters to include controlled crystal plane orientation during the deposition process itself. By adjusting deposition conditions (such as substrate temperature, deposition rate, or plasma conditions) to favor specific crystal orientations, the process remains a single deposition step while achieving the dual benefit of simplicity and eliminating subsequent forming requirements.
Solution Approach 2:
The deposition process is made multi-functional by simultaneously achieving both film formation and crystal orientation control in a single step. This universal approach combines the simplicity of direct deposition with the advantage of pre-oriented crystal structures, eliminating the need for separate forming processing.
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 manufacturing process by allowing the resistance change element to start in a low resistance initial state, eliminating the need for forming processing and facilitating easier production of both resistance change elements and nonvolatile memory devices.
Implementation Method 1
The memory layer is capable of reversibly transitioning between a first state and a second state due to at least one of a voltage and a current supplied via the first conductive layer and the second conductive layer. A resistance of the second state is higher than a resistance of the first state.
Implementation Method 2
A ratio of an intensity at a binding energy of 205 eV to an intensity at a binding energy of 207.5 eV of X-ray photoelectron spectroscopy of Nb included in the memory layer is 0.062 or less.
Data Source
AI summary
A resistance change element includes a first conductive layer, a second conductive layer, and a memory layer. The memory layer is provided between the first conductive layer and the second conductive layer. The memory layer is capable of reversibly transitioning between a first state and a second state due to at least one of a voltage and a current supplied via the first conductive layer and the second conductive layer. A resistance of the second state is higher than a resistance of the first state. The memory layer includes niobium oxide. One of a (100) plane, a (010) plane, and a (110) plane of the memory layer is oriented in a stacking direction from the first conductive layer toward the second conductive layer.