Embedded RRAM Structure with Doped Region for Fabrication
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Solution Overview
Problem
Conventional RRAM structures require multiple photomasks for definition and have limited flexibility in adjusting the thickness of the top electrode, metal oxide layer, and bottom electrode, making the fabrication process complex and inflexible.
Innovation Solution
An RRAM structure is embedded in the substrate with a bottom electrode, metal oxide layer, and top electrode, where a first doped region surrounds the bottom electrode, and a transistor is formed on the substrate with a gate structure, source, and drain, allowing for flexible thickness adjustment through chemical mechanical planarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional RRAM is inserted between metal interconnections by replacing plugs, then the RRAM can be integrated into existing interconnection structures, but several extra photomasks are required and the thickness of electrodes and metal oxide layer cannot be adjusted arbitrarily
Solution Approach 1:
The RRAM structure is segmented into distinct functional regions: a first doped region embedded in the substrate surrounding the bottom electrode, and a transistor disposed at one side of the RRAM. This segmentation allows independent optimization of each component's fabrication parameters, reducing the need for multiple photomasks while maintaining integration capability.
Solution Approach 2:
The invention transitions from planar insertion between metal interconnections to vertical embedding in the substrate. The RRAM is formed by filling a recess in the substrate with bottom electrode, metal oxide layer, and top electrode, allowing thickness adjustment independent of interconnection layer thickness constraints.
2Ease of manufacture
If the thickness of top electrode, bottom electrode and metal oxide layer is adjusted to match metal interconnection thickness, then the RRAM can be integrated with existing interconnections, but the fabrication process becomes less flexible and requires more photomasks
Solution Approach 1:
The RRAM structure employs local quality by creating a recess in the substrate with specific dimensions, allowing the electrodes and metal oxide layer to have optimized local thicknesses that differ from the surrounding metal interconnections. The first doped region also provides localized electrical properties distinct from the bulk substrate.
Solution Approach 2:
The invention changes the fabrication parameter space by allowing independent control of bottom electrode thickness, metal oxide layer thickness, and top electrode thickness through the recess depth and filling process, rather than being constrained to match a fixed metal interconnection thickness. This enables optimization of RRAM performance parameters.
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 simplifies the fabrication process by reducing the number of photomasks needed and allows for arbitrary adjustment of electrode thicknesses, enhancing the reliability of the RRAM by ensuring current flows through a deeper channel, thus improving the overall performance.
Implementation Method 1
A first doped region is embedded in the substrate and surrounds the bottom electrode
Implementation Method 2
a planarization process is performed to remove the bottom electrode, the metal oxide layer and the top electrode outside of the recess
Data Source
AI summary
An RRAM structure includes a substrate. An RRAM is embedded in the substrate. The RRAM includes a bottom electrode, a metal oxide layer and a top electrode. A first doped region is embedded in the substrate and surrounds the bottom electrode. A transistor is disposed on the substrate and at one side of the RRAM. The transistor includes a gate structure on the substrate. A source is disposed in the substrate and at one side of the gate structure. A drain is disposed in the substrate and at another side of the gate structure. The first doped region contacts the drain.