MIM Capacitor Electrode Treatment for Oxygen Vacancy Blocking
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Solution Overview
Problem
Existing Metal-Insulator-Metal (MIM) capacitors face reliability issues due to oxygen scavenging from the high-k dielectric layer by the first electrode, leading to oxygen vacancies and performance degradation.
Innovation Solution
A nitrogen-rich titanium oxide layer is formed by treating the oxide layer of the first electrode with nitrogen plasma and ammonia, followed by depositing a high-k dielectric layer, which reduces oxygen scavenging and enhances the capacitor's reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high-k dielectric layer is deposited over a metal electrode, then the capacitance density is improved, but oxygen vacancies form in the dielectric layer due to oxygen scavenging by the electrode
Solution Approach 1:
A titanium oxide layer is introduced as an intermediary between the metal electrode and the high-k dielectric layer. This intermediate layer acts as a buffer that prevents direct oxygen diffusion from the high-k dielectric to the metal electrode, thereby eliminating oxygen vacancies while preserving the high capacitance density benefit of the high-k dielectric material.
Solution Approach 2:
The capacitor structure employs a composite material system consisting of multiple layers: metal electrode, titanium oxide layer, and high-k dielectric layer. Each material is selected for its specific properties - the titanium oxide layer provides oxygen barrier functionality while the high-k dielectric provides high capacitance, creating a composite structure that achieves both high performance and reliability.
2Reliability
If a titanium oxide layer is formed between the electrode and high-k dielectric layer, then oxygen diffusion is blocked, but the manufacturing process complexity increases
Solution Approach 1:
The formation of the titanium oxide layer is merged with the existing capacitor manufacturing process by utilizing the same atomic layer deposition (ALD) equipment and process conditions already used for forming the high-k dielectric layer. This integration approach adds minimal process complexity while achieving the oxygen barrier function.
Solution Approach 2:
The titanium oxide layer is formed by adjusting deposition parameters (such as precursor flow rates, temperature, and cycle numbers) within the existing ALD process window. By changing process parameters rather than introducing new process equipment or fundamentally different deposition methods, the oxygen barrier function is achieved with minimal increase in 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 nitrogen-rich titanium oxide layer effectively blocks oxygen diffusion, improving the reliability and performance of the MIM capacitor by ensuring a uniform thickness and higher nitrogen content, meeting the required 10-year Time-Dependent Break Down (TDDB) specifications.
Implementation Method 1
performing a first treatment process using nitrogen plasma on a first oxide layer formed on the first electrode
Implementation Method 2
performing a second treatment process using ammonia
Data Source
AI summary
A method includes forming a first electrode, performing a first treatment process on a first oxide layer over the first electrode, wherein the first treatment process is performed using a first process gas comprising ammonia, depositing a high-k dielectric layer over the first oxide layer, forming a second electrode over the high-k dielectric layer, forming a first contact plug electrically connecting to the first electrode, and forming a second contact plug electrically connecting to the second electrode.