Phase Change Memory With Low-k Dielectric Heat Insulation
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Solution Overview
Problem
Phase change memory technologies face challenges in reducing power consumption and enhancing data retention and reliability, particularly due to thermal diffusion and parasitic capacitance issues in current device structures.
Innovation Solution
A phase change memory structure utilizing low-k dielectric material as a heat-insulating layer, surrounded by an anti-diffusion dielectric layer, to reduce thermal crosstalk and prevent phase change material diffusion, while using a CMOS-compatible fabrication method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional dielectric materials are used in phase change memory structures, then thermal diffusion occurs between adjacent memory cells, but using low-k dielectric material increases parasitic capacitance
Solution Approach 1:
The patent employs a composite dielectric structure consisting of a low-k dielectric layer (for thermal insulation) combined with a tunnel oxide layer and a blocking dielectric layer (for electrical isolation). This composite approach allows the structure to simultaneously achieve low thermal conductivity for reducing power consumption and high electrical insulation for maintaining data retention, resolving the contradiction between thermal management and electrical reliability.
Solution Approach 2:
The patent applies different dielectric materials with specific properties to different regions and functions within the memory structure. The low-k dielectric material is specifically positioned where thermal insulation is critical, while tunnel oxide and blocking dielectric layers are placed where electrical isolation is paramount. This localized material selection optimizes both thermal and electrical performance without compromising either aspect.
2Use of energy by moving object
If the contact area between electrode and phase change material is reduced to lower current consumption, then the heating efficiency decreases
Solution Approach 1:
The patent introduces a tunnel oxide layer and a blocking dielectric layer as thin film structures between the electrode and phase change material. These thin films serve as flexible thermal management interfaces that confine heat locally at the phase change material interface while maintaining small contact area for low current consumption. The thin film structure allows efficient heat transfer to the phase change material without excessive thermal diffusion to surrounding areas.
3Reliability
If low-k dielectric material is used as inter layer dielectrics, then parasitic capacitance is reduced, but thermal insulation performance deteriorates
Solution Approach 1:
The patent creates a composite dielectric system where low-k dielectric material is combined with tunnel oxide and blocking dielectric layers. The low-k material provides excellent electrical isolation for reduced parasitic capacitance and improved signal transmission, while the tunnel oxide and blocking dielectric layers contribute thermal insulation properties. This composite structure achieves both low parasitic capacitance and adequate thermal insulation simultaneously.
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 power consumption, enhances data retention, and improves reliability by minimizing thermal diffusion and parasitic capacitance, while maintaining compatibility with CMOS processes and scalability.
Implementation Method 1
low-k dielectric heat-insulating layer surrounding said heating electrode and reversible phase change resistor
Implementation Method 2
an anti-diffusion dielectric layer designed between said reversible phase change resistor and the low-k dielectric heat-insulating layer surrounding thereof
Implementation Method 3
a heating electrode on said diode; a reversible phase change resistor on said heating electrode
Data Source
AI summary
The present invention discloses a phase change memory structure having low-k dielectric heat-insulating material and fabrication method thereof, wherein the phase change memory cell comprises diode, heating electrode, reversible phase change resistor, top electrode and etc; the heating electrode and reversible phase change resistor are surrounded by low-k dielectric heat-insulating layer; an anti-diffusion dielectric layer is designed between the reversible phase change resistor and the low-k dielectric heat-insulating layer surrounding thereof. The present invention utilizes low-k dielectric material as heat-insulating material, thereby avoiding thermal crosstalk and mutual influence during operation between phase change memory cells, enhancing the reliability of devices, and eliminating the influence of temperature, pressure and etc. on phase change random access memory (PCRAM) data retention during the change from amorphous to polycrystalline states. Furthermore, an anti-diffusion dielectric layer is prepared between the low-k dielectric material and the phase change material, which can be used to prevent the elements of the phase change material from diffusing to low-k dielectric material. The fabrication process of said phase change memory is compatible with standard complementary metal-oxide semiconductor (CMOS) process and the chemical mechanical polishing (CMP) process with low pressure and light corrosion is adopted in polishing.