Transition-Metal Oxide Memory Cell With Four Stable Programmable States
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Solution Overview
Problem
Existing non-volatile memory devices based on Transition Metal Oxides exhibit a large statistical spread of resistance values and limited endurance, and programmable logic devices are less efficient in terms of power consumption and area usage compared to application-specific integrated circuits.
Innovation Solution
A programmable element with a transition-metal oxide base that includes mobile ions, such as oxygen vacancies, which can be altered by electric field, allowing for four distinct states through voltage pulses applied to the source, drain, and gate electrodes, reducing statistical spread and enhancing endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Transition Metal Oxide based non-volatile memory devices are used, then non-volatile memory functionality is achieved, but large statistical spread of resistance values and limited endurance occur
Solution Approach 1:
The patent changes the fundamental operating parameter from resistance-based storage to charge-based storage. The memory cell uses a floating gate electrode to store electrical charge, which modulates the threshold voltage of the transistor. This parameter change from resistance to charge/threshold voltage eliminates the statistical spread issue inherent in TMO materials while achieving non-volatile memory functionality with improved endurance.
Solution Approach 2:
The patent employs a composite structure combining a MOS transistor with a floating gate electrode made of different materials (e.g., polysilicon, metal). This composite approach integrates the reliability of CMOS transistors with the non-volatile storage capability of the floating gate, overcoming the limitations of single-material TMO-based memory devices.
2Adaptability or versatility
If programmable logic devices with memory and logic elements are used, then flexibility and re-programmability are achieved, but power consumption increases and area efficiency decreases
Solution Approach 1:
The patent merges the memory element and logic element into a single integrated structure using non-volatile CMOS technology. The floating gate transistor serves both as a memory cell and as a programmable logic element, eliminating the need for separate memory and logic components. This merging reduces area overhead and power consumption while maintaining re-programmability.
Solution Approach 2:
The non-volatile CMOS transistor with floating gate serves multiple functions: it acts as a memory element for data storage, a logic element for computation, and a programmable element for configuration. This multi-functionality allows a single device type to replace multiple specialized components, improving area efficiency and reducing overall power consumption.
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 programmable element achieves robustness against statistical resistance spread, increased information density, and improved energy efficiency, enabling efficient re-routing of signal paths and higher functionality per area in programmable logic circuits.
Implementation Method 1
a transition-metal oxide with mobile ions that are capable of drifting under an applied electric field
Implementation Method 2
an interface of a source and/or drain electrode material and the transition metal oxide base material forms an energy barrier for electron injection from the electrode into the base material and the energy barrier depends on a concentration of the mobile ions of the base material
Data Source
AI summary
A multi-terminal programmable element. The programmable element includes a source electrode and a drain electrode on a base. The programmable element includes reference voltage contact that is not in contact with the source or drain electrode. The base includes a transition-metal oxide with oxygen vacancies for drifting under an applied electric field. Further, materials of the source electrode and the base are selected such that an interface of a source and/or drain electrode material and the transition metal oxide base material forms an energy barrier for electron injection from the electrode into the base material. The energy barrier has a height that depends on an oxygen vacancy concentration of the base material. Four non-volatile states are programmable into the programmable element.