Recessed Antifuse Structures with Work Function Engineering
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Solution Overview
Problem
Current antifuse devices in integrated circuits face challenges in achieving smaller feature sizes and higher density, as well as improved reliability, particularly in controlling the initial breakdown point, as higher-density integrated circuit devices require more precise antifuse technology.
Innovation Solution
The use of recessed access devices (RAD) and spherical recessed access devices (SRAD) with multiple materials having different work function values, where the difference in work function values is about 0.2 eV or more, allows for controlled breakdown areas by layering materials with barrier layers to prevent dopant migration, and positioning these materials in trenches or spherical shapes to create specific breakdown locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional planar access devices are used, then manufacturing is simpler, but feature size cannot be reduced and density is limited
Solution Approach 1:
The patent transitions from planar (2D) access devices to recessed access devices that extend into the third dimension (vertical depth). The gate electrode and gate dielectric are formed in a recessed region beneath the substrate surface, enabling smaller footprint and higher density while maintaining manufacturability through vertical stacking rather than lateral expansion.
Solution Approach 2:
The recessed access device structure nests multiple components vertically: the gate dielectric is positioned within the recessed region, the gate electrode overlays the gate dielectric, and source/drain regions are formed adjacent to the gate structure. This nested arrangement compactly packs functional elements to achieve smaller feature sizes.
2Reliability
If higher-density integrated circuits are developed, then circuit capacity increases, but antifuse reliability and breakdown control deteriorate
Solution Approach 1:
The patent applies different materials with specific work function characteristics to different regions of the access device. The gate electrode uses a first material while the source/drain regions use a second material with a higher work function, creating localized electrical properties that control where breakdown occurs and ensure reliable operation in high-density circuits.
Solution Approach 2:
The patent modifies key electrical parameters including the work function difference between gate and source/drain materials, the thickness of the gate dielectric layer, and the doping concentrations in source/drain regions. These parameter adjustments enable precise control of breakdown voltage and location, maintaining reliability as circuit density increases.
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 enables the customization of antifuse breakdown points, enhancing the reliability and density of antifuse devices by providing controlled and tailored breakdown areas within integrated circuits and semiconductor devices, improving the functionality and performance of memory cells and other IC components.
Implementation Method 1
The use of recessed access devices (RAD) and spherical recessed access devices (SRAD) with multiple materials having different work function values, where the difference in work function values is about 0.2 eV or more, allows for controlled breakdown areas
Implementation Method 2
layering materials with barrier layers to prevent dopant migration
Implementation Method 3
when a high voltage exceeding the capacity of the antifuse is applied across the antifuse, the gate-oxide of the antifuse breaks down, creating an electrically conductive path through the antifuse
Data Source
AI summary
Antifuses having two or more materials with differing work function values may be fabricated as recessed access devices and spherical recessed access devices for use with integrated circuit devices and semiconductor devices. The use of materials having different work function values in the fabrication of recessed access device antifuses allows the breakdown areas of the antifuse device to be customized or predicted.