Integrated Schottky Select Device and Storage Element for Resistive Memory
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Solution Overview
Problem
Resistive memory cells in cross-point architectures face read disturbance issues due to current flow into unselected word lines during read operations, which reduces the ability to distinguish between data states and decreases output impedance.
Innovation Solution
The integration of a Schottky interface with a storage element and a select device structure within the resistive memory cell, which acts as a current limiter to prevent current flow into unselected word lines during read operations, allowing for high voltage bipolar programming while maintaining a suitable on/off current ratio for partial select read methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a 1D1R cross-point architecture is used, then memory density is improved, but read disturbance occurs due to current flow into unselected word lines
Solution Approach 1:
The select device and storage element are merged into a single integrated structure where the Schottky interface serves dual functions as both the select device and one electrode of the storage element. This integration eliminates the need for separate select device structures while maintaining the ability to prevent read disturbance through the Schottky barrier's natural current limiting properties.
Solution Approach 2:
The Schottky interface acts as an intermediary element that provides selective current conduction. It mediates between the access line and the storage element, allowing current to flow only when the full select voltage is applied across the entire memory cell, thereby preventing current leakage into unselected word lines while maintaining high memory density.
2Speed
If higher current densities are supported, then programming speed is improved, but read disturbance increases
Solution Approach 1:
The Schottky barrier height is dynamically controlled through band bending in response to applied voltages. During read operations with low voltages, the barrier prevents current flow. During programming with high voltages, the barrier becomes transparent, allowing high current densities to flow through the selected cell for fast programming while unselected cells remain protected.
Solution Approach 2:
The electrical parameters of the Schottky interface change dramatically with applied voltage. At low read voltages, the Schottky barrier presents high resistance to prevent read disturbance. At high programming voltages, the barrier height decreases and current conduction increases, enabling fast programming with high current densities through the selected cell only.
3Adaptability or versatility
If multiple material layers are used, then device functionality is improved, but physical size increases
Solution Approach 1:
The Schottky interface structure performs multiple functions simultaneously: it acts as the select device for current limiting, serves as one electrode of the storage element, and provides the Schottky barrier for selective conduction. This multi-functionality eliminates the need for separate select device material layers, reducing physical size while maintaining full device functionality.
Solution Approach 2:
The select device function and storage element electrode function are merged into the same physical structure. The Schottky interface that would traditionally be part of the select device is also used as an electrode for the storage element, consolidating multiple functional layers into a single integrated structure that reduces overall device footprint.
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 solution reduces the physical size of memory cells, supports higher current densities, and enhances signal-to-noise ratio during read and write operations, minimizing read and write disturb, and improving memory density by reducing material layers.
Implementation Method 1
a select device structure including a Schottky interface, and a storage element integrated with the select device structure such that an electrode corresponding to the Schottky interface serves as a first electrode of the storage element
Data Source
AI summary
Resistive memory cells including an integrated select device and storage element and methods of forming the same are described herein. As an example, a resistive memory cell can include a select device structure including a Schottky interface, and a storage element integrated with the select device structure such that an electrode corresponding to the Schottky interface serves as a first electrode of the storage element. The storage element can include a storage material formed between the first electrode and a second electrode.