Ultrafast Quench Nonvolatile Bistable Memory Device
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Solution Overview
Problem
Current non-volatile memory technologies, such as phase-change memories, face limitations in switching speed and material quality, leading to inefficiencies in data storage and high power consumption, while existing ultrafast switching methods do not effectively create metastable, textured states for long-term storage.
Innovation Solution
An ultrafast quench-based nonvolatile bistable memory device that utilizes an ultrashort laser pulse to rapidly cool a material, creating a metastable, textured state with distinct optical and electrical properties, allowing for rapid switching and long-term storage by modifying electronic, magnetic, and structural ordering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional phase-change memory materials are used with gradual thermal treatment, then material stability is maintained, but switching speed is slow and power consumption is high
Solution Approach 1:
The patent changes the fundamental parameter of heating rate from gradual (conventional) to ultrafast (10^12-10^14 K/s), enabling phase transitions to occur in picoseconds rather than milliseconds. This ultrafast quenching through the phase transition creates metastable textured states that are non-volatile, achieving both high speed and low power consumption by avoiding continuous heating requirements
Solution Approach 2:
The patent employs periodic ultrashort laser pulses to induce phase transitions. Each pulse creates a rapid thermal cycle that quenches the material through the phase transition point, forming metastable states. The periodic application of these pulses enables repeated writing and erasing operations with picosecond switching times and minimal energy input per cycle
2Speed
If conventional phase-change memory materials are used, then non-volatile storage is achieved, but switching time is on the order of nanoseconds or longer
Solution Approach 1:
The patent exploits phase transitions in chalcogenide materials (amorphous ↔ crystalline) but achieves them through ultrafast quenching rather than gradual heating. The rapid cooling rate (10^12-10^14 K/s) creates metastable textured crystalline states that are non-volatile at room temperature, while the transition itself occurs in picoseconds, simultaneously achieving fast switching and long-term storage
Solution Approach 2:
The patent introduces dynamic control over the phase transition process by using ultrashort laser pulses with durations of 10^-12 to 10^-14 seconds. This dynamic approach allows precise control of the heating and cooling rates, enabling the material to be quenched through the phase transition point and trapped in metastable states, achieving both speed and stability
3Speed
If ultrashort laser pulses are used to create metastable states, then switching speed is enhanced, but material quality and structural uniformity may deteriorate
Solution Approach 1:
The patent applies ultrashort laser pulses to create localized regions of metastable textured states within the material. Each pulse affects only a specific volume, creating spatially controlled domains with distinct optical and electrical properties. This local modification approach maintains overall material quality while enabling high-speed writing through precise spatial control
Solution Approach 2:
The patent uses ultrashort laser pulses to pre-heat the material rapidly to the phase transition temperature before the extremely fast cooling occurs. This preliminary heating action, combined with the subsequent ultrafast quench, ensures uniform phase transition throughout the illuminated volume, maintaining material quality while achieving picosecond switching speeds
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
Enables ultrafast writing and erasing of data with switching times under 50 fs and picosecond erasure, achieving persistent changes in material properties for high-speed, non-volatile memory storage with improved efficiency and reduced power consumption.
Implementation Method 1
switching a material between an equilibrium state A to a persistent state B by means of an ultrafast quench through a phase transition
Implementation Method 2
application of a ultrashort laser pulse, typically 50 fs in length, which enables the material to cool sufficiently rapidly (quench) through a phase transition
Implementation Method 3
enables the material to cool sufficiently rapidly (quench) through a phase transition to cause the formation of metastable textures
Implementation Method 4
State B is characterized by a textured structure, which is metastable and cannot be formed by gradual thermal treatment of the material
Implementation Method 5
The materials properties of the thus created state B is sufficiently different from state A, to be detected by a change of optical reflectivity or transmissivity
Data Source
AI summary
The invention refers to an ultrafast quench based nonvolatile bistable device which consists of an active material on a passive or active substrate which changes its physical properties, after exposure to a sufficiently temporally short external perturbation causing an ultrafast quench. The perturbation can be from an external ultrashort laser pulse or ultrafast electrical pulse from an electrooptic device or any other generator of ultrashort pulses. This change of the materials properties can be detected as a change of optical properties or electrical resistance. The dielectric properties can be reverted back to their original state by the application of a heat pulse applied by an electrical heater within the device or an external laser.