Capacitor Monoclinic Dielectric Leak Current Reduction
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Solution Overview
Problem
Capacitors used in image sensors with high-k dielectric layers face issues with high leak current and inferior insulating properties, particularly when heat-treated in a hydrogen atmosphere, leading to degraded performance and increased noise levels.
Innovation Solution
A capacitor design featuring a dielectric layer made of hafnium oxide or zirconium oxide with a monoclinic crystal structure and a hydrogen concentration of 2.5×10^21 atoms/cm^3 or less, where the dielectric layer is laminated between electrodes and subjected to specific heat treatments in nitrogen or reduced pressure atmospheres to minimize leak current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high-k dielectric layer is used in a capacitor for image sensors, then the capacitance is improved, but the leak current increases and insulating properties deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the crystal structure (monoclinic phase), thickness (12 nm or more), and hydrogen concentration (2.5×10^21 atoms/cm³ or less) of the high-k dielectric layer to optimize the balance between capacitance and leak current, resolving the contradiction between high capacitance and low leak current
Solution Approach 2:
The patent uses composite material structures by combining high-k dielectric materials (hafnium oxide or zirconium oxide) with specific crystal structures and controlled hydrogen content, creating a composite dielectric system that achieves both high capacitance and low leak current
2Reliability
If heat treatment is performed in a hydrogen atmosphere, then the insulating properties are improved, but the leak current increases
Solution Approach 1:
The patent applies preliminary anti-action by performing heat treatment in a nitrogen atmosphere or reduced pressure atmosphere before hydrogen atmosphere treatment, which prevents hydrogen from excessively increasing leak current while still improving insulating properties through the sequential treatment process
3Reliability
If the dielectric layer thickness is increased, then the insulating properties are improved, but the capacitance density decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the dielectric layer thickness to be 12 nm or more, which provides sufficient insulation while maintaining high capacitance density through the high-k material properties, resolving the contradiction between insulation and capacitance density
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 solution effectively reduces leak current and enhances the insulating properties of the capacitor, leading to improved image sensor accuracy and reliability by minimizing noise and kTC noise reduction.
Implementation Method 1
The dielectric layer has a monoclinic crystal system structure
Implementation Method 2
A concentration of hydrogen in the dielectric layer is 2.5×10^21 atoms/cm^3 or less
Data Source
AI summary
A capacitor includes a first electrode; a second electrode facing the first electrode; and a dielectric layer which is disposed between the first electrode and the second electrode. The dielectric layer is made of at least one selected from the group consisting of a hafnium oxide and a zirconium oxide. A thickness of the dielectric layer is 12 nm or more. The dielectric layer has a monoclinic crystal system structure. A concentration of hydrogen in the dielectric layer is 2.5×1021 atoms/cm3 or less.