Phonon-Blocking Insulating Layer for Memory Cell Heat Retention
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Solution Overview
Problem
As solid state non-volatile memory devices decrease in form factor, the required anisotropic field increases, leading to higher switching current and low operating margin due to the high thermal conductivity of most memory materials, which dissipates applied heat and complicates memory function.
Innovation Solution
A non-volatile memory cell with a ferromagnetic free layer and pinned layer separated by a thermally and electrically insulative phonon-blocking insulating layer that retains heat while allowing electrical signal transmission through conductive features, reducing switching current and maintaining memory operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the form factor of solid state non-volatile memory devices is decreased, then the device size is reduced, but the required anisotropic field increases leading to higher switching current
Solution Approach 1:
The patent changes the thermal parameter of the memory cell by introducing an insulating layer with low thermal conductivity between the ferromagnetic layers. This parameter change allows heat to be retained within the cell, reducing the switching current requirement despite the reduced device size
Solution Approach 2:
The insulating layer acts as a thermal intermediary that blocks phonon transport between the ferromagnetic free layer and pinned layer. This intermediary prevents heat dissipation to the substrate, maintaining the thermal energy needed for switching in compact devices
2Reliability
If most solid state memory materials are used, then electrical conductivity is achieved, but thermal conductivity increases causing heat dissipation
Solution Approach 1:
The patent segments the memory cell structure into distinct functional layers: ferromagnetic free layer, insulating layer, and pinned layer. The insulating layer is specifically segmented to provide phonon-blocking properties while maintaining electrical functionality through tunneling
Solution Approach 2:
The patent employs composite material structure combining ferromagnetic materials with an insulating material that has specific phonon-blocking properties. This composite approach allows simultaneous achievement of electrical conductivity for memory operation and thermal insulation for heat retention
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 effectively reduces the switching current and field requirements by retaining heat within the memory cell, enhancing memory function and efficiency while maintaining reliable data storage and transfer rates in compact form factors.
Implementation Method 1
an insulating layer that is constructed of an electrically and thermally insulative material that blocks phonons
Implementation Method 2
thermally and electrically insulative phonon-blocking insulating layer that retains heat
Implementation Method 3
tunnel junction, ferromagnetic free layer, pinned layer
Data Source
AI summary
An apparatus and associated method for a non-volatile memory cell with a phonon-blocking insulating layer. In accordance with various embodiments, a magnetic stack has a tunnel junction, ferromagnetic free layer, pinned layer, and an insulating layer that is constructed of an electrically and thermally insulative material that blocks phonons while allowing electrical transmission through at least one conductive feature.