Phase-Change Memory Device Carbon Nitrogen Chalcogenide Target
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Solution Overview
Problem
Conventional phase-change random access memory (PRAM) devices using GST compounds face issues with rapid material deterioration, high set resistance, and poor adhesion between electrodes and the phase-change material layer, leading to reduced data retention and increased driving currents.
Innovation Solution
A chalcogenide compound target with a high carbon content and low metal content, or carbon, metal, and nitrogen, is used to form a phase-change material layer, enhancing electrical characteristics and adhesion, thereby stabilizing phase transitions and improving device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GST compound is used as phase-change material, then the device structure is simple and manufacturing is easy, but the material deteriorates rapidly and data retention is reduced
Solution Approach 1:
The patent uses composite phase-change materials consisting of chalcogenide compounds (such as GST) combined with additional elements like carbon, nitrogen, or metal elements. This composite approach maintains the phase-change properties of the base material while adding elements that improve stability and reduce deterioration, thereby enhancing data retention without significantly complicating the manufacturing process
Solution Approach 2:
The patent modifies the compositional parameters of the phase-change material by controlling the content of additional elements (carbon: 1-30 at%, nitrogen: 1-20 at%, metal elements: 1-15 at%). By optimizing these compositional parameters, the material achieves improved stability and data retention while maintaining manufacturability within existing fabrication processes
2Device complexity
If GST compound is used as phase-change material, then the device structure is simple, but the set resistance is relatively great
Solution Approach 1:
The patent introduces composite phase-change materials with chalcogenide compounds combined with carbon, nitrogen, or metal elements. These additional elements modify the electrical properties of the material, specifically reducing the set resistance while maintaining the overall device structure and complexity at acceptable levels
Solution Approach 2:
The patent optimizes the compositional parameters by controlling the concentration of additional elements (carbon: 1-30 at%, nitrogen: 1-20 at%, metal elements: 1-15 at%). This parameter optimization achieves the desired reduction in set resistance while keeping the device structure relatively simple
3Ease of manufacture
If GST compound is used as phase-change material, then the manufacturing process is simple, but the adhesion between electrodes and phase-change material layer is poor
Solution Approach 1:
The patent employs composite phase-change materials where chalcogenide compounds are combined with carbon, nitrogen, or metal elements. These additional elements enhance the adhesion properties of the phase-change material layer to the electrodes, improving interfacial bonding without significantly altering the manufacturing process
Solution Approach 2:
The patent optimizes compositional parameters by controlling the content of additional elements (carbon: 1-30 at%, nitrogen: 1-20 at%, metal elements: 1-15 at%). This optimization improves adhesion strength while maintaining ease of manufacture within existing fabrication capabilities
4Productivity
If driving current is reduced to improve integration degree, then the integration degree increases, but the set resistance is greatly increased when using GST compound doped with nitrogen
Solution Approach 1:
The patent uses composite phase-change materials combining chalcogenide compounds with multiple additional elements (carbon, nitrogen, and/or metal elements). This multi-element composite approach allows for reduced driving current to achieve desired integration度 while preventing excessive increase in set resistance through the synergistic effects of the combined elements
Solution Approach 2:
The patent optimizes compositional parameters by controlling the concentrations of multiple additional elements (carbon: 1-30 at%, nitrogen: 1-20 at%, metal elements: 1-15 at%). This multi-parameter optimization enables the device to achieve high integration度 with reduced driving current while maintaining set resistance within acceptable ranges
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 solution results in a phase-change memory device with improved crystallized temperature, resistance, reduced set resistance, and driving current, while maintaining durability and sensing margin.
Implementation Method 1
a phase-change material layer formed on the lower electrode by a sputtering process using a first target including carbon or metal carbide, and a second target including a chalcogenide compound
Implementation Method 2
The phase-change memory device stores information using a resistance difference between an amorphous phase and a crystalline phase of a phase-change material layer composed of a chalcogenide compound
Data Source
AI summary
A method of manufacturing a phase-change memory device comprises forming a contact region on a substrate, forming a lower electrode electrically connected to the contact region, forming a phase-change material layer on the lower electrode using a chalcogenide compound target including carbon and metal, or carbon, nitrogen and metal, and forming an upper electrode on the phase-change material layer.