Thin Film Capacitor Recesses Suppress Leakage Current
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Solution Overview
Problem
Existing thin film capacitors face challenges in suppressing leakage current while maintaining a thin dielectric layer, as increasing the number of dielectric layers thickens the capacitor, and doping methods struggle to adjust aluminum content effectively.
Innovation Solution
A thin film capacitor design featuring a first electrode layer with recesses and a dielectric layer where the recess depth to thickness ratio is between 0.05 and 0.5, dispersing recesses at 50 to 300 per 100 μm², and incorporating protrusions adjacent to recesses to enhance adhesion and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-layer dielectric thin film is formed to suppress leakage current, then leakage current is reduced, but the dielectric layer thickness increases making it difficult to improve capacitance
Solution Approach 1:
The invention applies local quality by creating recesses at specific locations on the electrode layer surface rather than uniformly thickening the entire dielectric layer. The recesses are formed locally at regions where leakage current tends to concentrate, increasing the insulation distance only where needed while maintaining thin dielectric layers in other areas, thus preserving capacitance.
Solution Approach 2:
The invention transitions from a two-dimensional planar dielectric layer to a three-dimensional structure with recesses. By introducing depth variation (H/T ratio) into the dielectric layer configuration, the effective insulation distance is increased in the vertical dimension at recess locations without increasing the overall lateral dimensions or average thickness of the dielectric layer.
2Reliability
If aluminum doping is applied to improve leakage current characteristic, then leakage current is suppressed, but it is difficult to adjust aluminum amount and maintain thin dielectric layer
Solution Approach 1:
The invention changes the parameter from material composition (aluminum doping concentration) to geometric configuration (recess depth and distribution). This allows continuous adjustment of leakage current suppression by varying the H/T ratio and recess density without being constrained by fixed doping levels, providing greater adaptability in optimizing both leakage performance and dielectric layer thickness.
Data Source
AI summary
Provided is a thin film capacitor that includes: a first electrode layer having a principal surface in which a plurality of recesses are provided; a dielectric layer laminated on the principal surface of the first electrode layer; and a second electrode layer laminated on the dielectric layer. When a depth of the recess is defined as FL and a thickness of the dielectric layer is defined as T, H/T is 0.05 or more and 0.5 or less.