DRAM Capacitor Interface Blocking Film for High Capacitance Reliability
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Solution Overview
Problem
As semiconductor devices become larger and more integrated, there is a need to increase capacitance in DRAM devices to improve refresh characteristics and yield, which existing methods struggle to achieve effectively due to limitations in dielectric films and electrode interfaces.
Innovation Solution
A capacitor structure is developed with a lower electrode comprising a lower electrode film, a lower insertion electrode film, and a lower interface electrode film, along with an interface blocking film, where the interface blocking film contains a first metal oxide, and the lower interface electrode film contains a second conductive metal oxide, all stacked on a substrate with a capacitor dielectric film, optimizing the metal oxide compositions and thicknesses to enhance capacitance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dielectric film having a high dielectric constant is used in a capacitor, then capacitance is increased, but reliability deteriorates due to interface defects and oxygen vacancies
Solution Approach 1:
A lower interface electrode film made of conductive metal oxide is introduced as an intermediary layer between the lower electrode and the capacitor dielectric film. This intermediate layer improves interface contact quality and reduces oxygen vacancies, thereby enhancing reliability while maintaining high capacitance performance.
Solution Approach 2:
The lower electrode structure is designed as a composite multi-layer system including a lower electrode film, a lower interface electrode film made of conductive metal oxide, and optionally a lower insertion electrode film. This composite structure combines materials with different properties to simultaneously achieve high capacitance and high reliability.
2Quantity of substance
If the contact area between the lower electrode and the dielectric film is increased, then capacitance is increased, but device complexity increases
Solution Approach 1:
The interface electrode film is selectively formed only at the lower electrode-dielectric film interface where improved contact is needed, rather than uniformly throughout the entire electrode structure. This localized approach improves capacitance without unnecessarily increasing overall device 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 proposed capacitor structure effectively increases capacitance, improves dielectric characteristics, and reduces oxygen vacancies, leading to enhanced semiconductor device performance and reliability by optimizing the metal oxide compositions and thicknesses in the capacitor structure.
Implementation Method 1
the interface blocking film is in contact with the capacitor dielectric film and the lower interface electrode film, wherein the interface blocking film includes a first metal oxide containing a first metal element, the lower interface electrode film includes a second conductive metal oxide containing a second metal element different from the first metal element
Data Source
AI summary
A capacitor structure is provided. The capacitor structure comprises an upper electrode, a lower electrode including a lower electrode film and a lower interface electrode film, a capacitor dielectric film between the lower electrode and the upper electrode, and an interface blocking film between the lower electrode and the capacitor dielectric film, the interface blocking film being in contact with the capacitor dielectric film and the lower interface electrode film, wherein the interface blocking film includes a first metal oxide containing a first metal element, the lower interface electrode film includes a second conductive metal oxide containing a second metal element different from the first metal element, the capacitor dielectric film does not include the first metal oxide, and a thickness of the lower interface electrode film is greater than that of the interface blocking film.