Titanium Getter Layer in MIM Capacitors for Hydrogen Isolation
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Solution Overview
Problem
Hydrogen ions left behind during the fabrication of metal-insulator-metal (MIM) devices can accumulate at interfaces, leading to dielectric breakdown and reduced device lifetime due to their tendency to produce hydrogen gas, causing interface delamination and arcing.
Innovation Solution
Incorporating a titanium getter layer with a higher affinity for hydrogen than the dielectric layer, either above or below the electrodes, to absorb hydrogen ions and prevent their accumulation in the dielectric layer, thereby mitigating damage and increasing device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a getter layer is added to absorb hydrogen ions, then device reliability is improved, but device complexity increases
Solution Approach 1:
A titanium getter layer is introduced as an intermediary component between the electrodes and dielectric layer. This getter layer specifically absorbs hydrogen ions that migrate during device operation, preventing them from reaching and damaging the dielectric layer. The getter layer acts as a protective mediator that intercepts harmful hydrogen ions before they can cause interface delamination or dielectric breakdown, thereby improving device reliability without requiring fundamental changes to the existing MIM structure.
2Reliability
If the titanium getter layer is placed above the top electrode, then hydrogen absorption is effective, but the fabrication process becomes more complex
Solution Approach 1:
The titanium getter layer is deposited in advance during the fabrication process, before the device begins operation. By pre-positioning the getter layer above the top electrode or below the bottom electrode, the structure is prepared to immediately absorb hydrogen ions as soon as they begin to migrate. This preliminary placement ensures that the getter layer is in optimal position to intercept hydrogen ions before they can accumulate at critical interfaces, making the absorption process automatic and effective without requiring additional operational steps.
3Duration of action of stationary object
If a getter layer is implemented to prevent hydrogen accumulation, then device lifetime is extended, but manufacturing steps increase
Solution Approach 1:
The getter layer utilizes a specific material parameter - titanium's high affinity for hydrogen - to achieve effective hydrogen ion absorption. By selecting titanium as the getter layer material, the patent leverages its inherent chemical properties to preferentially bind hydrogen ions, forming titanium hydride. This parameter-based approach (material selection) enables the getter layer to provide prolonged protection against hydrogen damage, extending device lifetime while requiring only a single additional deposition step in the fabrication process.
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 titanium getter layer effectively absorbs hydrogen ions, reducing the risk of dielectric breakdown and extending the lifetime of MIM devices by isolating them from the dielectric layer, regardless of the polarity of the applied voltage bias.
Implementation Method 1
a titanium getter layer having a second affinity for hydrogen that is greater than the first affinity
Data Source
AI summary
In some embodiments, the present disclosure relates to a method of forming a metal-insulator-metal (MIM) device. The method may be performed by depositing a bottom electrode layer over a substrate, depositing a dielectric layer over the bottom electrode layer, depositing a top electrode layer over the dielectric layer, and depositing a first titanium getter layer over the top electrode layer. The first titanium getter layer, the top electrode layer, and the dielectric layer are patterned to expose a peripheral portion of the bottom electrode layer. A passivation layer is deposited over the substrate, the first titanium getter layer, and the peripheral portion of the bottom electrode layer.