Thin Film Capacitor Flatting Layer for Roughness Control
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Solution Overview
Problem
Thin film capacitors face challenges in achieving high capacitance due to limitations in the number of dielectric layers that can be stacked, as the roughness of electrode layers affects the crystallinity and permittivity of the dielectric layer, leading to deteriorated characteristics and leakage issues.
Innovation Solution
A thin film capacitor design with alternately stacked electrode layers and dielectric layers, where the electrode layers have a lower surface roughness than the dielectric layer, ensuring flat interfaces and secure capacitance and dielectric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple dielectric layers and electrode layers are stacked to increase capacitance, then the capacitance increases, but the surface roughness increases and dielectric characteristics deteriorate
Solution Approach 1:
A flatting layer is formed on the lower electrode before depositing the dielectric layer. This preliminary action creates a flat surface that prevents roughness from propagating to subsequent layers, allowing multiple layers to be stacked without deteriorating dielectric characteristics.
Solution Approach 2:
The flatting layer acts as an intermediary between the lower electrode and the dielectric layer. It mediates the surface roughness issue by providing a flat interface for dielectric deposition while being electrically connected to the lower electrode, thus allowing capacitance enhancement through layer stacking without roughness propagation.
2Ease of manufacture
If dielectric layer is deposited on rough electrode layer, then the electrode layer can be formed, but the crystallinity and permittivity of dielectric layer deteriorate
Solution Approach 1:
The flatting layer is formed as a preliminary structure before dielectric layer deposition. This preliminary flat surface ensures that subsequent dielectric layers can be deposited with excellent crystallinity and permittivity, while the electrode layer can still be formed on the lower electrode without difficulty.
3Quantity of substance
If the number of stacked layers is increased, then the capacitance increases, but the leakage characteristics through grain boundary deteriorate
Solution Approach 1:
By forming a flatting layer before dielectric layer deposition, the surface roughness is prevented from propagating to subsequent layers. This ensures uniform grain formation and excellent leakage characteristics even when multiple layers are stacked to increase capacitance.
Data Source
AI summary
A thin film capacitor includes a body including a lower electrode formed on a substrate, a plurality of first electrode layers, and a plurality of second electrode layers stacked alternately with the plurality of first electrode layers, with one of the dielectric layers interposed therebetween. The lower electrode and the first electrode layer have the same polarity as each other, and surface roughness of the first and second electrode layers is less than that of the dielectric layers, thereby securing capacitance and characteristics of the dielectric layers.