Radiation-Heated Phase Change Memory Cell for Low Power Operation
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Solution Overview
Problem
Conventional phase change memory technologies require high electric power for heating, leading to large transistor sizes and potential failure due to high power demands, especially for the RESET state which necessitates more significant transistors than those needed for the SET state.
Innovation Solution
The use of a heat transfer structure activated by electromagnetic radiation to indirectly heat a phase change material, reducing the need for high electric power and allowing smaller transistor sizes by leveraging radiation-induced heating to achieve the required temperature profiles for phase changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrical current is used to heat the phase change material for programming, then the phase change can be achieved, but high power consumption and large transistor sizes are required
Solution Approach 1:
The patent introduces a heater electrode as an intermediary component that converts electromagnetic radiation into heat, which then transfers to the phase change material. This mediator approach allows indirect heating, reducing the power burden on transistors while achieving the required temperature increase for phase change programming.
Solution Approach 2:
The patent replaces the conventional electrical heating mechanism (Joule heating through current) with electromagnetic radiation-induced heating. This substitution eliminates the need for high-current transistors, as the heating is achieved through radiation absorption by the heater electrode rather than direct electrical current through the memory cell.
2Speed
If high current density is applied to achieve rapid cooling for amorphous phase, then the RESET state can be programmed, but transistor size must be increased to handle the power
Solution Approach 1:
The heater electrode serves as a mediator that can be rapidly heated and cooled by controlling the electromagnetic radiation input. This allows fast cooling rates for amorphous phase formation without requiring large transistors to switch high currents, as the thermal control is decoupled from the transistor switching capability.
Solution Approach 2:
The patent employs pulsed electromagnetic radiation to achieve periodic heating and cooling cycles. By applying radiation pulses of appropriate duration and intensity, rapid cooling can be achieved for RESET operations without requiring continuously high current capability from transistors, thus reducing transistor size requirements.
3Use of energy by moving object
If electromagnetic radiation is used to heat the phase change material, then power consumption is reduced, but an additional heating mechanism is required
Solution Approach 1:
The heater electrode performs multiple functions: it serves as both the heating element that converts electromagnetic radiation to heat and as part of the memory cell structure. This multi-functionality approach adds the radiation heating capability without proportionally increasing device complexity, as the heater integrates into the existing memory cell architecture.
Solution Approach 2:
The heater electrode is designed to convert electromagnetic radiation directly into heat through its material properties, eliminating the need for separate power management circuitry or additional active heating components. The structure serves itself by inherently converting the radiation input into the required thermal energy for phase change programming.
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 approach enables phase change memory cells to be programmed and erased with reduced power consumption, allowing for smaller transistor sizes and increased reliability by eliminating the need for high electric power heating, thus addressing the limitations of conventional methods.
Implementation Method 1
a heat transfer structure (103) arranged to be heated by electromagnetic radiation (106) impinging on the heat transfer structure (103)
Implementation Method 2
a phase change structure (104) connected to the heat transfer structure (103) and being convertible between a crystalline phase and an amorphous phase when the radiation (106) impinges on the heat transfer structure (103)
Implementation Method 3
the phase change structure (104) is thermally coupled to the heat transfer structure (103)
Data Source
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AI summary
An electronic device (100) comprising a heat transfer structure (103) and a phase change structure (104) which is convertible between two phase states by heating, wherein the phase change structure (104) is electrically conductive in at least one of the two phase states, wherein the heat transfer structure (103) is arranged to be heated by radiation (106) impinging on the heat transfer structure (103), wherein the phase change structure (104) is thermally coupled to the heat transfer structure (103) so that the phase change structure (104) is convertible between the two phase states when the radiation (106) impinges on the heat transfer structure (103).