TiN/Ta2O5/TiN Capacitor Reoxidation via N2O Plasma
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Solution Overview
Problem
Current reoxidation methods for Ta2O5 layers in TiN/Ta2O5/TiN capacitors result in inhomogeneous outcomes, often increasing leakage current and dielectric relaxation factor, and are not suitable for low-temperature integration with metal-insulator-metal structures.
Innovation Solution
A method involving plasma-enhanced atomic layer deposition followed by N2O plasma reoxidation of the Ta2O5 layer, controlled to maintain substrate temperature between 300 and 400°C and N2O pressure between 10 and 3,000 Pa, ensuring precise oxidation without affecting the TiN support, with the goal of reducing leakage current and dielectric relaxation factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional reoxidation methods are applied to the Ta2O5 layer, then the oxidation process can be completed, but the results become inhomogeneous and leakage current increases
Solution Approach 1:
The patent applies parameter changes by controlling the oxygen partial pressure within a specific range (1-2000 Pa, preferably 10-30 Pa) and maintaining substrate temperature between 200-250°C during the plasma reoxidation process. These controlled parameter changes enable homogeneous oxidation of the Ta2O5 layer while preventing excessive oxidation that would increase leakage current, thus resolving the contradiction between oxidation completeness and oxidation homogeneity.
2Reliability
If reoxidation is performed to improve Ta2O5 layer quality, then oxygen vacancies are reduced, but processing temperature must be kept below 400°C to preserve interconnect integrity
Solution Approach 1:
The patent resolves this contradiction by changing the processing parameters, specifically maintaining substrate temperature between 200-250°C (well below the 400°C limit) while controlling oxygen partial pressure and plasma power. This enables effective reoxidation of the Ta2O5 layer to reduce oxygen vacancies and improve dielectric quality without exceeding the temperature threshold that would damage the underlying interconnects.
3Reliability
If plasma reoxidation is applied to reduce oxygen vacancies, then dielectric quality improves, but leakage current may increase if parameters are not controlled
Solution Approach 1:
The patent controls multiple parameters simultaneously to resolve this contradiction: oxygen partial pressure (1-2000 Pa), substrate temperature (200-250°C), and plasma power. By optimizing these parameters together, the reoxidation process effectively reduces oxygen vacancies to improve dielectric quality while preventing the formation of defects that would increase leakage current.
Solution Approach 2:
The patent implements feedback control by monitoring the oxidation process and adjusting plasma power and oxygen partial pressure dynamically. This feedback mechanism ensures that the Ta2O5 layer is reoxidized sufficiently to reduce oxygen vacancies while stopping before excessive oxidation occurs that would create leakage paths, thus simultaneously improving dielectric quality and maintaining low leakage current.
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 method effectively decreases leakage current and maintains a low dielectric relaxation factor, ensuring the Ta2O5 layer is uniformly reoxidized with a controlled interface thickness less than 2 nm, meeting stringent operational temperature requirements.
Implementation Method 1
submitting the obtained structure to an N2O plasma for a duration sufficient to oxidize the Ta2O5 layer
Implementation Method 2
oxidize the Ta2O5 layer without oxidizing the TiN support
Implementation Method 3
a plasma enhanced atomic layer deposition method has been provided to form the Ta2O5 layer
Implementation Method 4
phases of tantalum deposition from a precursor, currently, the so-called TBTDET product
Data Source
AI summary
A method for manufacturing a TiN/Ta2O5/TiN capacitor, including the steps of forming a Ta2O5 layer on a TiN support by a plasma-enhanced atomic layer deposition method, or PEALD; and submitting the obtained structure to an N2O plasma for a duration sufficient to oxidize the Ta2O5 layer without oxidizing the TiN support.