MIM Capacitor Interface Layers for Better TDDB Reliability
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Solution Overview
Problem
Existing MIM capacitors suffer from poor time-dependent dielectric breakdown (TDDB) performance due to the formation of non-stoichiometric metal oxide layers at the interface between conductor plates and high-K dielectric layers, which are prone to failure.
Innovation Solution
The formation of MIM capacitors involves depositing metal oxide layers between conductor plates using atomic layer deposition (ALD) to ensure the same metal element composition, preventing the formation of non-stoichiometric layers and enhancing TDDB performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fabrication processes are used to form MIM capacitors, then manufacturing simplicity is maintained, but non-stoichiometric metal oxide layers form at the interface between conductor plates and high-K dielectric layers, leading to poor TDDB performance and reduced reliability
Solution Approach 1:
A metal oxide layer is deposited on the conductor plate surface before forming the high-K dielectric layer. This preliminary action prevents the formation of non-stoichiometric metal oxide layers at the interface during subsequent processing, thereby improving TDDB performance without significantly complicating the overall fabrication process
Solution Approach 2:
A metal oxide layer is introduced as an intermediary between the conductor plate and the high-K dielectric layer. This intermediate layer acts as a buffer that prevents direct interaction between the conductor and high-K dielectric, eliminating the formation of harmful non-stoichiometric metal oxide layers and improving capacitor reliability
2Reliability
If metal oxide layers are deposited using ALD to prevent non-stoichiometric layer formation, then TDDB performance is improved, but manufacturing complexity and process steps increase
Solution Approach 1:
The metal oxide layer is deposited using ALD as a preliminary step before high-K dielectric formation. This advance preparation ensures stoichiometric composition and prevents subsequent interface degradation, improving TDDB performance while integrating smoothly into existing fabrication workflows
Solution Approach 2:
ALD is used to precisely control the deposition parameters of the metal oxide layer, ensuring optimal thickness and stoichiometric composition. By adjusting deposition parameters such as temperature, pressure, and precursor flow rates, the process achieves high-quality interfaces while maintaining reasonable manufacturing efficiency
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 approach improves the TDDB performance of MIM capacitors by preventing the formation of poor-quality metal oxide layers, thereby increasing their reliability and longevity.
Implementation Method 1
The formation of MIM capacitors involves depositing metal oxide layers between conductor plates using atomic layer deposition (ALD)
Data Source
AI summary
Semiconductor structures and methods are provided. An exemplary method includes depositing forming a first metal-insulator-metal (MIM) capacitor over a substrate and forming a second MIM capacitor over the first MIM capacitor. The forming of the first MIM capacitor includes forming a first conductor plate over a substrate, the first conductor plate comprising a first metal element, conformally depositing a first dielectric layer on the first conductor plate, the first dielectric layer comprising the first metal element, forming a first high-K dielectric layer on the first dielectric layer, conformally depositing a second dielectric layer on the first high-K dielectric layer, the second dielectric layer comprising a second metal element, and forming a second conductor plate over the second dielectric layer, the second conductor plate comprises the second metal element.