Three-Region Capacitor Dielectric for DRAM Leakage Control
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Solution Overview
Problem
The miniaturization of capacitors in semiconductor devices has led to challenges in optimizing their structure for improved electrical characteristics and reliability, particularly in dynamic random-access memory (DRAM) devices.
Innovation Solution
The semiconductor device incorporates a dielectric layer with a specific structure comprising a first region, a second region, and a third region, where the third region includes a first oxide and a second oxide with a different valence, and the thickness and metal ratio are optimized to enhance capacitance without increasing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitor size is miniaturized to support high integration, then the device density increases, but the electrical characteristics and reliability deteriorate
Solution Approach 1:
The dielectric layer is divided into three regions with different compositions: a first region with high-k material for capacitance, a second region with low-defect material for reliability, and a third region with dual oxide for optimized electrical characteristics. This local differentiation allows each region to perform its specific function optimally while maintaining overall capacitor performance in miniaturized structures.
Solution Approach 2:
The patent employs composite dielectric structures combining multiple materials: a first oxide (e.g., HfO2), a second oxide (e.g., SiO2), and their combinations in different regions. The third region specifically uses a composite of first oxide and second oxide to achieve optimized dielectric properties, enabling both high capacitance and low leakage current in miniaturized capacitors.
2Quantity of substance
If the dielectric layer thickness is reduced to miniaturize the capacitor, then the capacitance density increases, but the leakage current increases
Solution Approach 1:
Different regions of the dielectric layer are assigned different materials optimized for their specific functions: the second region uses low-defect materials to minimize leakage, while the first region provides high-k capacitance. This local optimization allows thin overall structure while maintaining low leakage through strategic material placement.
Solution Approach 2:
The third region acts as an intermediary layer between the first and second regions, combining both first oxide and second oxide materials. This intermediate structure with dual oxide composition helps transition between the high-k region and the low-leakage region, optimizing both capacitance and leakage characteristics simultaneously.
3Device complexity
If a single-material dielectric layer is used to simplify the structure, then the manufacturing complexity decreases, but the electrical characteristics cannot be optimized
Solution Approach 1:
The dielectric layer is segmented into three distinct regions along the thickness direction, each with specific material compositions optimized for different functions. This segmentation enables independent optimization of capacitance (first region), leakage control (second region), and overall electrical characteristics (third region), achieving superior performance compared to uniform single-material structures.
Solution Approach 2:
Each region of the dielectric layer has locally optimized material properties: the first region uses high-k material for maximum capacitance, the second region uses low-defect material for minimum leakage, and the third region uses dual oxide for balanced electrical characteristics. This local quality differentiation achieves optimal electrical performance while maintaining a relatively simple three-layer structure.
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 improves the electrical characteristics and reliability of capacitors by enhancing capacitance while maintaining low leakage current, thereby supporting high integration and miniaturization needs.
Implementation Method 1
a dielectric layer covering the plurality of lower electrodes; and an upper electrode covering the dielectric layer. The dielectric layer includes a first region in contact with the plurality of lower electrodes; a second region in contact with the upper electrode; and a third region between the first region and the second region
Data Source
AI summary
A semiconductor device includes a substrate, lower electrodes on the substrate, a dielectric layer covering the lower electrodes, and an upper electrode covering the dielectric layer. The dielectric layer includes a first region in contact with the lower electrodes, a second region in contact with the upper electrode, and a third region between the first and second regions. The third region includes a first insertion layer including a first oxide including a first metal having a first valence and a second oxide including a second metal having a second valence different from the first valence. A thickness of the dielectric layer is about 40 Å to about 60 Å. A thickness of the first insertion layer is about 3 Å to about 10 Å. A ratio of the second metal to total elements in the dielectric layer is about 5 at % to about 15 at %.