A multiply-add engine with monolithically integrated 3D memristor crossbar/CMOS hybrid circuit

Area of Science:

• Materials Science
• Electrical Engineering
• Computer Engineering

Background:

• Silicon (Si) based complementary metal-oxide semiconductor (CMOS) technology faces scaling limitations, hindering further advancements in computing and memory.
• Memristive devices offer a promising alternative for next-generation memory and computing applications due to their high density and unique properties.

Purpose of the Study:

• To demonstrate a functional 3D hybrid CMOS/memristor circuit (CMOL architecture) for advanced computing and memory applications.
• To integrate multiple layers of memristive crossbars monolithically onto a CMOS substrate for enhanced functionality.

Main Methods:

• Fabrication of a 2-layer memristive crossbar structure monolithically integrated on a pre-fabricated CMOS substrate.
• Operation and characterization of the integrated memristive devices, focusing on analog switching behavior and multi-level storage.
• Demonstration of dot-product operations using 2D and 3D memristive crossbars to showcase their potential as multiply-add engines.

Main Results:

• Successful monolithic integration and operation of a 2-layer memristive crossbar circuit with underlying CMOS circuitry.
• Memristive devices exhibited controlled analog switching, tunable characteristics, and stable multi-level operation.
• The 3D CMOL hybrid circuit effectively performed dot-product operations, validating its use as a multiply-add engine.

Conclusions:

• The developed 3D CMOL hybrid circuit represents a significant advancement in overcoming CMOS scaling bottlenecks.
• This technology enables terabit-scale memory and highly efficient computing paradigms.
• This work presents the first demonstration of a functional 3D CMOL hybrid circuit, paving the way for future integrated electronic systems.