Carbon Electrode Capacitor Structure for Low-Leakage High-k Dielectrics
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Solution Overview
Problem
In the semiconductor industry, capacitors face challenges in increasing capacitance while maintaining reliability due to issues with dielectric breakdown and leakage current, especially when using high-permittivity materials like HfO2 with polycrystalline silicon electrodes, which result in reduced withstand voltage and increased surface roughness.
Innovation Solution
A capacitor design featuring a dielectric layer with a thickness of 10 nm or more, made from high-k materials such as hafnium oxide or zirconium oxide, with a first electrode containing carbon at an elemental percentage of 30 atomic % or less, and plasma treatment to reduce carbon content at the interface, improving insulating properties and reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-permittivity materials like HfO2 are used in the dielectric layer, then capacitance is improved, but withstand voltage deteriorates due to dielectric breakdown
Solution Approach 1:
The patent changes the chemical composition parameter of the electrode material by incorporating carbon elements into the polycrystalline silicon electrode. This parameter change modifies the electrode's interaction with the high-k dielectric layer, preventing dielectric breakdown while maintaining high capacitance. The carbon incorporation alters the electrode's surface properties and chemical reactivity, resolving the contradiction between using high-permittivity materials and maintaining reliability.
Solution Approach 2:
The patent creates a composite electrode structure by combining polycrystalline silicon with carbon elements. This composite material approach allows the electrode to simultaneously provide the electrical conductivity of silicon and the dielectric stability provided by carbon, enabling the use of high-k dielectric materials without suffering from breakdown issues. The composite structure resolves the contradiction by integrating materials with complementary properties.
2Quantity of substance
If high-permittivity materials like HfO2 are used in the dielectric layer, then capacitance is improved, but surface roughness worsens
Solution Approach 1:
The patent modifies the electrode's chemical composition by adding carbon elements, which changes the surface interaction characteristics. This parameter change prevents excessive surface roughness formation when high-k dielectric materials are deposited, while still allowing the dielectric layer to achieve its full permittivity potential for high capacitance.
3Object-generated harmful factors
If carbon content in the first electrode is reduced to 30 atomic % or less, then leakage current is reduced, but manufacturing complexity increases due to plasma treatment requirements
Solution Approach 1:
The patent applies plasma treatment to the electrode surface before depositing the dielectric layer. This preliminary action removes excess carbon from the electrode surface, ensuring that the carbon content at the interface is 30 atomic % or less. By performing this carbon removal step in advance, the patent prevents leakage current issues without requiring complex post-processing steps, thus managing manufacturing complexity effectively.
Solution Approach 2:
The patent extracts excess carbon from the electrode surface through plasma treatment. This extraction process removes the harmful carbon elements that would otherwise cause high leakage current, while preserving the necessary carbon content for maintaining electrode integrity. The selective removal of excess carbon resolves the contradiction between reducing leakage current and managing manufacturing complexity.
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 solution results in a capacitor with high capacitance, improved withstand voltage, and reduced leakage current, enhancing the reliability and performance of capacitors in integrated circuits and image sensors.
Implementation Method 1
a dielectric layer disposed between the first and second electrodes... The dielectric layer has a thickness of 10 nm or more... made from high-k materials such as hafnium oxide or zirconium oxide
Implementation Method 2
plasma treatment to reduce carbon content at the interface
Data Source
AI summary
A capacitor includes a first electrode, a second electrode facing the first electrode, and a dielectric layer disposed between the first and second electrodes and being in contact with each of the first and second electrodes. The dielectric layer has a thickness of 10 nm or more. The first electrode contains carbon. At the interface between the dielectric layer and the first electrode, an elemental percentage of carbon is 30 atomic % or less.