DRAM Capacitor Dielectric Structure for Low Leakage Scaling
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Solution Overview
Problem
As semiconductor devices downscale, the reduced thickness of capacitor dielectric layers in DRAM devices leads to increased leakage current, which is not effectively addressed by existing technologies.
Innovation Solution
The integration of a dielectric layer structure comprising a first dielectric layer with grains extending from one electrode to the other, and a second dielectric layer with a higher bandgap energy material surrounding the sidewalls of the grains, effectively blocking leakage current paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the capacitor dielectric layer is reduced due to downscaling, then the device size is reduced, but the leakage current increases
Solution Approach 1:
The dielectric layer is segmented into multiple distinct layers: a first dielectric layer with high crystallinity and a second dielectric layer with higher bandgap energy. This segmentation allows each layer to perform specialized functions - the first layer provides capacitive function while the second layer blocks leakage current paths at grain boundaries, thereby reducing overall leakage current despite reduced total thickness
Solution Approach 2:
The patent employs a composite dielectric structure combining two different dielectric materials with complementary properties. The first dielectric material (e.g., barium strontium titanate) provides high dielectric constant for capacitance, while the second dielectric material (e.g., aluminum oxide or silicon oxide) provides higher bandgap energy for leakage suppression. This composite approach enables simultaneous achievement of small size and low leakage current
2Productivity
If the equivalent oxide thickness is reduced to downscale the device, then the device density increases, but the leakage current through the dielectric layer increases
Solution Approach 1:
The patent applies local quality by making different regions of the dielectric structure have different properties. The second dielectric layer is specifically positioned at grain boundaries and interfaces where leakage current tends to flow, providing localized leakage blocking. This targeted approach allows the bulk of the dielectric to maintain thin dimensions for high density while specific critical regions have enhanced leakage suppression properties
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 configuration reduces the equivalent oxide thickness and minimizes leakage current while maintaining high crystallinity of the dielectric layers, even with reduced total thickness, thereby enhancing the performance of DRAM devices.
Implementation Method 1
the second dielectric material includes a material having bandgap energy which is higher than bandgap energy of the first dielectric material
Data Source
AI summary
An integrated circuit device includes a lower electrode, an upper electrode, and a dielectric layer structure between the lower electrode and the upper electrode, the dielectric layer structure including a first surface facing the lower electrode and a second surface facing the upper electrode. The dielectric layer structure includes a first dielectric layer including a first dielectric material and a plurality of grains extending from the first surface to the second surface and a second dielectric layer including a second dielectric material and surrounding a portion of a sidewall of each of the plurality of grains of the first dielectric layer in a level lower than the second surface. The second dielectric material includes a material having bandgap energy which is higher than bandgap energy of the first dielectric material.