Resistive Memory Cell with Solid State Diode Mitigates Sneak Path Currents
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Solution Overview
Problem
Resistive switching memory cells face challenges such as slow switching speeds, small on/off resistance ratios, thermal instability, and the sneak path problem, which leads to increased power consumption and memory cell errors due to undesired current flowing through neighboring cells in crossbar arrays.
Innovation Solution
A two-terminal solid state memory cell with a p-n diode structure, comprising a conductive ion layer, an electrically resistive diffusive layer permeable to ions, and semiconductor layers with specific doping concentrations, which mitigates sneak path currents by providing a non-linear current-voltage relationship and rectifier characteristics, allowing for efficient programming and erasing with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a crossbar array architecture is used for high memory density, then memory density increases, but sneak path currents increase causing power consumption and errors
Solution Approach 1:
A diode component is introduced as an intermediary element between the resistive switching component and the bitline in the memory cell. This diode acts as a mediator that allows current to flow in only one direction, thereby blocking sneak path currents that would otherwise flow through neighboring cells during read operations, while still permitting legitimate read currents to pass through the selected memory cell.
2Ease of manufacture
If conventional resistive switching memory cells are used, then manufacturing simplicity is maintained, but switching speed is slow and thermal stability is poor
Solution Approach 1:
The memory cell employs a composite structure combining a resistive switching component (made from materials like metal oxide, chalcogenide, or polymer) with a diode component (made from semiconductor materials such as silicon carbide, gallium nitride, or organic semiconductors). This composite structure leverages the advantages of both materials: the resistive switching component provides ease of manufacture and non-volatile storage, while the diode component enhances switching speed and thermal stability.
3Loss of energy
If a p-n diode structure is added to reduce sneak path currents, then power consumption decreases, but device complexity increases
Solution Approach 1:
The diode component and resistive switching component are merged into a single integrated memory cell structure where the diode is positioned in series with the resistive switching component between the bitline and wordline. This merging approach allows the two components to work together as a unified device that reduces sneak path currents and power consumption without requiring separate independent circuits or additional control logic.
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 significantly reduces sneak path currents, enhances memory cell reliability, and enables higher memory density with lower manufacturing costs, while maintaining fast switching speeds and non-volatile data storage capabilities.
Implementation Method 1
an ion source layer comprising unbound conductive ions and an insulator layer that is at least in part permeable to the unbound conductive ions of the ion source layer
Implementation Method 2
the p semiconductor layer and the n semiconductor layer are exclusive to the memory cell and form a solid-state p-n diode
Data Source
AI summary
Providing for a solid state memory cell having a resistive switching memory cell with rectifier characteristics is described herein. By way of example, the solid state memory cell can have one or more layers creating a resistive switching device capable of achieving and maintaining different electrical resistances in response to different voltages applied to the solid state memory cell. Moreover, the solid state memory cell can comprise two or more layers creating a solid state diode device electrically in series with the resistive switching device. The solid state diode device can be configured to permit very low current through the solid state memory cell at voltages less than a breakdown voltage or reverse breakdown voltage. The rectifier characteristics can mitigate sneak path currents in a crossbar memory array, or similar array, facilitating greater sensing margin, reduced likelihood of memory errors, greater die concentration, fast switching times, and other benefits.