MIM Capacitor Oxygen Gradient Electrode Structure
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Solution Overview
Problem
In semiconductor devices, the reduction in capacitor area due to increased integration density leads to challenges in achieving desired capacitance, and the use of high dielectric films can result in reduced capacitance and increased leakage current, while metal-insulator-metal (MIM) capacitors face issues with electrode reaction and resistance degradation.
Innovation Solution
A MIM capacitor design with a layered upper electrode structure, including a protective film between the dielectric film and the upper electrode, where the concentration of oxygen atoms decreases from the bottom to the top, reducing oxygen diffusion and maintaining desired resistance, comprising a first electrode with a high concentration of oxygen, a second electrode with a lower concentration, and a third electrode substantially free of oxygen, to prevent capacitance reduction and resistance increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high dielectric film is used to increase capacitance, then capacitance is improved, but leakage current increases and capacitance reduction occurs due to electrode reaction
Solution Approach 1:
A protective film is introduced as an intermediary layer between the high dielectric film and the upper electrode. This protective film prevents direct contact and chemical reaction between the electrode and dielectric film, thereby reducing leakage current and preventing capacitance reduction while allowing the high dielectric film to maintain its capacitance-enhancing function.
Solution Approach 2:
The upper electrode is divided into multiple layers with different materials and oxygen concentrations. The first electrode layer has high oxygen concentration to prevent diffusion into the dielectric film, the second layer has intermediate concentration to balance protection and conductivity, and the third layer has low oxygen concentration to minimize resistance. This segmentation allows simultaneous optimization of protection and electrical performance.
2Stability of the object's composition
If a protective film is added between the dielectric film and upper electrode to reduce reactions, then capacitance stability is improved, but device complexity increases
Solution Approach 1:
The protective film function is merged with the upper electrode structure by making the first layer of the upper electrode serve as both the protective barrier and part of the conductive path. This integration reduces the need for separate protective layers and simplifies the overall structure while maintaining capacitance stability.
3Quantity of substance
If the thickness of dielectric film is reduced to increase capacitance, then capacitance is improved, but leakage current characteristics deteriorate
Solution Approach 1:
The capacitor employs a composite structure combining a high dielectric constant material (such as barium strontium titanate or hafnium oxide) with a protective film layer. This composite approach allows the use of thinner dielectric films to achieve higher capacitance while the protective film prevents degradation and leakage current issues that would normally accompany thin film usage.
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 design effectively prevents capacitance reduction and resistance increase in MIM capacitors, ensuring stable performance and high integration density in semiconductor devices by controlling oxygen diffusion and maintaining optimal electrode resistance.
Implementation Method 1
The upper electrode includes a first electrode including a first material, e.g., oxygen atoms, at a first concentration. A second electrode is disposed on the first electrode and includes the first material at a second concentration. A third electrode is disposed on the second electrode and has a third concentration of the first material.
Implementation Method 2
If the thickness of a dielectric film used in a capacitor is reduced in order to increase capacitance, leakage current characteristics may be deteriorated. Therefore, a dielectric film having a high dielectric constant, i.e., a high dielectric film, may be employed.
Data Source
AI summary
A semiconductor device includes a MIM capacitor on a substrate. The MIM capacitor includes a dielectric region and first and second electrodes on opposite sides of the dielectric region. At least one of the first and second electrodes, e.g., an upper electrode, includes an oxygen diffusion blocking material, e.g., oxygen atoms, at a concentration that decreases in a direction away from the dielectric region. The at least one of the first and second electrodes may include a first layer having a first concentration of the oxygen diffusion blocking material and a second layer on the first layer and having a second concentration of the oxygen diffusion blocking material less than the first concentration. The at least one of the first and second electrodes may further include a third layer on the second layer and having a concentration of the oxygen diffusion blocking material less than the second concentration.