Sb2Te3 Superlattice Phase Change Memory with Zr Doping
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Solution Overview
Problem
Phase change memory devices face challenges in reducing operating current and power consumption, particularly in the resetting operation, which is crucial for increasing storage density and reducing power consumption in solid storage devices.
Innovation Solution
A superlattice phase change memory structure is developed, incorporating alternately stacked layers of Sb2Te3 and GeTe with Zr added to the Sb2Te3 layers, enhancing resistance and reducing reset current through controlled resistivity adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional phase change memory composed of Ge2Sb2Te5 is used, then the memory can store information by changing resistance between amorphous and crystalline states, but the operating current and power consumption are high
Solution Approach 1:
The patent uses a composite superlattice structure consisting of alternating GeTe and Sb2Te3 layers. This composite material approach creates a novel phase change memory that combines the advantages of both materials while achieving lower operating current and power consumption compared to conventional Ge2Sb2Te5-based memories.
Solution Approach 2:
The phase change memory layer is segmented into multiple thin alternating layers of GeTe and Sb2Te3, forming a superlattice structure. This segmentation allows for better control of phase transition and resistance states, contributing to reduced operating current while maintaining reliability.
2Use of energy by moving object
If the operating current of phase change memory is reduced, then power consumption decreases and storage density increases, but the resistance in low resistance state becomes insufficient
Solution Approach 1:
The patent introduces Zn doping specifically in the Sb2Te3 layers of the superlattice structure. This local modification of composition allows for independent optimization of resistance characteristics in different regions of the material, enabling better control over the low resistance state while maintaining low power operation.
Solution Approach 2:
The patent modifies the compositional parameter by adding Zn to the Sb2Te3 layers. This parameter change directly affects the electrical resistance characteristics, enabling the memory to achieve sufficient resistance in the low resistance state while operating at reduced current levels.
3Use of energy by moving object
If a superlattice structure of GeTe and Sb2Te3 is used, then operating current is reduced compared to Ge2Sb2Te5, but the resistance in low resistance state needs further increase for optimal performance
Solution Approach 1:
The patent enhances the superlattice structure by incorporating Zn-doped Sb2Te3 layers. This composite material approach maintains the low operating current advantage of the GeTe-Sb2Te3 superlattice while improving the resistance ratio through compositional modification.
Solution Approach 2:
By changing the compositional parameter (adding Zn), the patent optimizes the resistance characteristics of the superlattice structure. This parameter modification enables the memory to achieve both low operating current and sufficient resistance in the low resistance state for optimal performance.
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 superlattice structure achieves a significant increase in resistance in the low resistance state, leading to lower power consumption and higher storage density with reduced operating currents, enhancing the performance and efficiency of phase change memory cells.
Implementation Method 1
Sb2Te3 layers containing Zr... controlled resistivity adjustments... achieves a significant increase in resistance in the low resistance state
Implementation Method 2
The memory having a superlattice structure of alternately stacked GeTe and Sb2Te3 layers switches between a high-resistance crystalline state and a low-resistance crystalline state
Data Source
AI summary
A superlattice phase change memory capable of increasing a resistance in a low resistance state is provided. The phase change memory includes a first electrode, a second electrode provided on the first electrode, and a phase change memory layer having a superlattice structure between the first electrode and the second electrode, the superlattice structure including to repeatedly formed layers of Sb2Te3 and GeTe. The phase change memory layer having the superlattice structure includes a Sb2Te3 layer containing Zr in contact with the first electrode.