TiN MIM Capacitor Electrodes With Graded Density Interfaces
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Solution Overview
Problem
The integration of metal-insulator-metal (MIM) capacitors in semiconductor devices faces challenges due to interface intermixing and interdiffusion between TiN and high-K dielectric materials, leading to reliability issues and suboptimal performance.
Innovation Solution
A multi-step biasing power scheme is employed during magnetron sputtering to form TiN electrodes with varying density levels, reducing intermixing and interdiffusion by controlling the sputtering yield and bias power levels, thereby improving mechanical, electrical, and uniformity properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnetron sputtering is used to form TiN electrodes, then the electrodes can be deposited with controlled properties, but interface intermixing and interdiffusion between TiN and high-K dielectric materials occur leading to reliability issues
Solution Approach 1:
The patent applies dynamic control of bias power during the sputtering process, transitioning from a static single-step biasing approach to a dynamic multi-step biasing approach. The bias power is systematically increased through multiple steps during deposition, allowing the process conditions to evolve and optimize the electrode structure in real-time, thereby reducing interface intermixing while maintaining controlled density.
Solution Approach 2:
The patent changes the bias power parameter systematically during the sputtering process. By increasing bias power through multiple steps, the process alters the sputtering yield and ion bombardment energy, which controls the density profile of the deposited TiN electrode. This parameter change approach enables better interface stability by reducing intermixing while achieving the desired electrode properties.
2Device complexity
If single-step biasing is used during sputtering, then the process is simple, but the TiN electrode density is uniform and does not optimize interface properties
Solution Approach 1:
The patent segments the single-step biasing process into multiple steps, where bias power is applied in discrete increments during the sputtering process. This segmentation allows different bias power levels to be applied at different stages of deposition, creating a density gradient in the TiN electrode that optimizes interface properties while reducing intermixing, without requiring overly complex process equipment.
3Productivity
If bias power is increased to improve sputtering yield, then deposition efficiency increases, but damage to the high-K layer increases leading to reduced reliability
Solution Approach 1:
The patent applies preliminary low bias power at the beginning of the sputtering process to initiate deposition with minimal damage to the high-K layer. As the electrode thickness increases, bias power is gradually increased in subsequent steps. This preliminary action approach allows the process to build up the electrode structure before applying higher energy bombardment, thereby improving sputtering yield while protecting the underlying high-K dielectric layer.
Solution Approach 2:
The patent dynamically adjusts bias power during the deposition process rather than applying high bias power from the start. The bias power evolves through multiple steps, increasing as the electrode structure develops. This dynamic approach allows the process to adapt to the changing conditions, improving productivity as deposition progresses while minimizing damage to the high-K layer during the critical early stages.
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 multi-step biasing power scheme enhances the reliability and performance of MIM capacitors by reducing damage to the high-K layer, improving time-dependent dielectric breakdown and maintaining stochiometric composition, resulting in better mechanical and electrical properties.
Implementation Method 1
depositing the first electrode includes depositing the first electrode via plasma-based physical vapor deposition (PVD) techniques using a power source to cause magnetron sputtering
Data Source
AI summary
A fabrication method includes: forming, above a substrate, a first electrode having a varying density that increases from a first density level at a bottom surface of the first electrode to a second density level that is higher than the first density level at a top surface of the first electrode; forming a high-K dielectric layer over the first electrode; and forming a second electrode over the HK dielectric layer having a varying density that increases from a third density level at a bottom surface of the second electrode that bonds to the HK dielectric layer to a fourth density level that is higher than the third density level at a top surface of the second electrode.