Organic Molecular Layer Rectifier for RRAM Scaling
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Solution Overview
Problem
Scaling down rectifier elements in resistive random access memory (RRAM) is challenging due to increased tunneling currents, which can cause malfunctions and hinder the miniaturization of memory cells necessary for increased storage capacity.
Innovation Solution
Incorporating an organic molecular layer with specific fused polycyclic units having distinct HOMO levels between conductive layers in RRAM memory cells, which acts as a rectifier to prevent leakage currents and stabilize the memory function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pn diode is used as a rectifier element in RRAM, then rectification property is achieved, but scaling down to 10 nm or smaller is difficult due to increased tunneling current
Solution Approach 1:
The patent changes the material parameter from inorganic semiconductor to organic molecule, specifically selecting molecules with appropriate HOMO levels to achieve rectification while enabling scaling to 10 nm or smaller dimensions
Solution Approach 2:
The patent creates a composite structure combining organic molecular layer with inorganic conductive layers (electrodes and variable resistance layer), where the organic component provides rectification and the inorganic components provide conductivity and memory function
2Productivity
If memory cell size is reduced to increase storage capacity, then productivity is improved, but leakage current increases causing malfunction
Solution Approach 1:
The organic molecular layer acts as an intermediary between the variable resistance layer and the electrode, providing rectification function that prevents leakage current while allowing the memory cell to be scaled down for increased storage capacity
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 organic molecular layer effectively prevents leakage currents, enabling stable operation of scaled-down RRAM memory cells with increased capacity and reliability by disrupting tunneling probabilities and maintaining rectification properties.
Implementation Method 1
a reduction in size increases a tunneling current
Implementation Method 2
Each of the organic molecules includes a first fused polycyclic unit having a first HOMO (highest occupied molecular orbital) level, a second fused polycyclic unit having a second HOMO level higher in energy than the first HOMO level
Data Source
AI summary
A memory device according to an embodiment includes a first conductive layer, a second conductive layer, a variable resistance layer disposed between the first conductive layer and the second conductive layer, and an organic molecular layer disposed between the variable resistance layer and the second conductive layer and containing organic molecules. Each of the organic molecules includes a first fused polycyclic unit having a first HOMO level, a second fused polycyclic unit having a second HOMO level higher in energy than the first HOMO level, and a third fused polycyclic unit disposed between the first fused polycyclic unit and the second fused polycyclic unit. The third fused polycyclic unit has a third HOMO level higher in energy than the first HOMO level and the second HOMO level.