AI Accelerator MRAM PCM Same-Level Integration
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Solution Overview
Problem
Conventional AI accelerators face integration challenges in placing high-density memory and non-volatile resistive memory on the same level, leading to reduced processing speed and increased energy consumption due to the distance between memory and computation units.
Innovation Solution
Integrating phase change memory (PCM) and magnetoresistive random access memory (MRAM) at the same metal level within an integrated circuit, allowing both to be closely proximate to the computation unit, thereby improving processing speed and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-density memory and non-volatile resistive memory are placed on different levels, then manufacturing complexity is reduced, but processing speed decreases and energy consumption increases due to distance between memory and computation units
Solution Approach 1:
The patent transitions from vertical stacking (different metal levels) to lateral integration (same metal level) by introducing a recessed bottom electrode structure. This dimensional change allows both high-density memory and non-volatile resistive memory to coexist at the same integration level, reducing the distance to computation units and improving processing speed while maintaining manufacturability through standardized CMOS-compatible processes.
2Loss of energy
If high-density memory and non-volatile resistive memory are placed on the same level, then processing speed improves and energy consumption reduces, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating a recessed bottom electrode structure specifically for the non-volatile resistive memory portion while keeping the high-density memory bottom electrode at the standard level. This localized structural modification enables same-level integration and reduced energy consumption without requiring complete redesign of the entire memory stack, thereby maintaining compatibility with existing manufacturing processes.
3Adaptability or versatility
If PCM bottom electrode is recessed to lower height, then integration at same metal level is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces an intermediary dielectric layer that fills the recessed portion of the PCM bottom electrode. This dielectric mediator enables the PCM bottom electrode to be recessed to the required depth while maintaining planarity and electrical isolation, thereby achieving same-level integration without excessive manufacturing precision requirements. The dielectric layer acts as a buffer that absorbs the height difference.
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 integration enhances processing speed and reduces energy consumption by bringing high-density memory closer to the computation unit, while maintaining non-volatile data storage capabilities.
Implementation Method 1
PCMs contain phase-change materials (such as alloys containing Tellurium) and may alter the states (e.g., crystalline and amorphous phases) of the PCM using heat
Implementation Method 2
The MTJ configuration creates electron tunneling and electrons can tunnel from one plate to the other. The amount of tunneling changes the resistance of the MTJ and the data is stored in the MRAM using the changes in resistance
Data Source
AI summary
An integrated circuit, a system, and a method to integrate phase change memory and magnetoresistive random access memory within a same integrated circuit in a system. The integrated circuit may include an MRAM and a PCM. The MRAM may include an MRAM bottom electrode, an MRAM stack, and an MRAM top electrode. The PCM may include a PCM bottom electrode, where the PCM bottom electrode has a lower height than the MRAM bottom electrode, a phase change material, and a PCM top electrode.