Dual Encapsulation Structure for Hydrogen-Resistant Ferroelectric Capacitors
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Solution Overview
Problem
Integration of capacitor devices with ferroelectric or paraelectric materials on the same plane as interconnects is challenging due to hydrogen damage, and existing methods struggle to form effective barrier layers, especially as device spacing decreases, necessitating alternative integration methods for high-density capacitor arrays.
Innovation Solution
A dual hydrogen barrier system is implemented, comprising an insulative hydrogen barrier directly adjacent to the memory device and a conductive hydrogen barrier integrated into the contact electrode, along with a high-density, amorphous dielectric layer to prevent hydrogen diffusion, allowing for the integration of ferroelectric and paraelectric capacitors in high-density arrays without spacer layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If capacitor devices with ferroelectric or paraelectric materials are integrated on the same plane as interconnects, then high-density capacitor arrays can be achieved, but hydrogen damage occurs due to hydrogen diffusion from interconnects
Solution Approach 1:
A dual barrier layer system is introduced as an intermediary between the capacitor device and the surrounding environment. The first barrier layer (conductive hydrogen barrier) and second barrier layer (insulative hydrogen barrier) act as mediators that selectively block hydrogen diffusion pathways while allowing the capacitor device to function normally integrated with interconnects on the same plane.
Solution Approach 2:
The hydrogen barrier system uses composite material structure combining two different barrier layers with complementary properties. The conductive barrier layer (e.g., titanium nitride, tungsten nitride) provides hydrogen blocking while maintaining electrical conductivity, and the insulative barrier layer (e.g., silicon nitride, silicon oxide) provides additional hydrogen blocking with electrical insulation, creating a composite protection system.
2Productivity
If spacing between devices is scaled to increase density, then high-density capacitor arrays are achieved, but formation of effective barrier layers becomes challenging
Solution Approach 1:
The barrier layer formation process transitions from planar deposition to conformal deposition in three-dimensional structures. The barrier layers are formed conformally on the sidewalls and top surfaces of the capacitor device, allowing effective coverage even when lateral spacing is reduced, by utilizing vertical dimension for layer thickness control.
Solution Approach 2:
The barrier protection is segmented into two distinct barrier layers with different material properties and functions. The first barrier layer is formed directly on the capacitor device, and the second barrier layer is formed over the first layer, creating segmented protection zones that can be independently optimized for different spacing requirements.
3Reliability
If a single insulative barrier layer is used to protect capacitor devices, then hydrogen diffusion is blocked, but electrical connectivity is compromised
Solution Approach 1:
Different regions of the barrier system have different electrical properties tailored to local requirements. The first barrier layer is made conductive to maintain electrical connectivity for signal transmission, while the second barrier layer is made insulative to provide enhanced hydrogen blocking where electrical conductivity is not required, achieving local optimization of both properties.
Solution Approach 2:
The dual barrier layer system performs multiple functions simultaneously: the conductive barrier layer provides both hydrogen blocking and electrical conductivity for signal paths, while the insulative barrier layer provides hydrogen blocking and electrical insulation for isolation. This multi-functional design resolves the contradiction between barrier effectiveness and connectivity.
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 dual hydrogen barrier effectively protects capacitor devices from hydrogen damage, enabling the integration of high-density capacitor arrays with improved reliability and density by preventing hydrogen diffusion, even in tightly spaced configurations.
Implementation Method 1
a high-density, amorphous dielectric layer to prevent hydrogen diffusion
Data Source
AI summary
A device includes, in a first region, a first conductive interconnect, an electrode structure on the first conductive interconnect, where the electrode structure includes a first conductive hydrogen barrier layer and a first conductive fill material. A memory device including a ferroelectric material or a paraelectric material is on the electrode structure. A second dielectric includes an amorphous, greater than 90% film density hydrogen barrier material laterally surrounds the memory device. A via electrode including a second conductive hydrogen barrier material is on at least a portion of the memory device. A second region includes a conductive interconnect structure embedded within a less than 90% film density material.