MIM Capacitor Dielectric Stack Using Composite Metal Oxides
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Solution Overview
Problem
There is a challenge in maintaining high storage capacitance in capacitors as integrated circuit density increases, particularly due to increased leakage current in metal-insulator-metal (MIM) constructions and difficulties in depositing oxide-containing capacitor dielectric materials for metal-containing electrodes.
Innovation Solution
The use of a capacitor dielectric region comprising multiple metal oxide materials, such as Al2O3, ZrO2, and TiO2, with specific thicknesses and configurations to achieve a high dielectric constant while minimizing leakage current, including the deposition and annealing of these materials to form a crystalline structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal-insulator-metal (MIM) construction is used to increase cell capacitance, then capacitance increases, but leakage current significantly increases
Solution Approach 1:
The patent employs a composite dielectric structure consisting of multiple metal oxide layers (such as HfO2, Al2O3, TiO2, ZrO2) with different properties. Each layer contributes differently to the overall dielectric performance, allowing the capacitor to achieve high capacitance while maintaining low leakage current through the synergistic combination of materials with complementary characteristics.
Solution Approach 2:
The patent applies different metal oxide materials to different regions or layers of the dielectric stack, where each material is strategically selected for its specific properties. For example, certain layers are optimized for high dielectric constant to boost capacitance, while adjacent layers are optimized for low leakage characteristics, creating localized functional zones within the dielectric region.
2Quantity of substance
If oxide-containing capacitor dielectric materials are deposited to form capacitor dielectric region, then dielectric constant increases, but deposition becomes problematic for metal-containing capacitor electrodes
Solution Approach 1:
The patent divides the dielectric region into multiple discrete layers of different metal oxide materials rather than using a single homogeneous material. This segmentation allows each layer to be deposited using optimized processes suitable for that specific material, avoiding the deposition problems associated with attempting to deposit a complex mixed oxide in a single step.
Solution Approach 2:
The patent performs preliminary deposition of metal oxide layers before final electrode formation or before subsequent processing steps. This sequencing allows the dielectric materials to be deposited under controlled conditions that are optimal for each material type, preventing contamination or deposition issues that would occur if electrodes were formed first.
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
This configuration results in a capacitor dielectric region with a dielectric constant of at least 35 and leakage current no greater than 1×10−7 amps/cm2, effectively addressing the capacitance and leakage issues in existing capacitor designs.
Implementation Method 1
a capacitor dielectric region (16) having a dielectric constant k of at least 35 and leakage current no greater than 1×10−7 amps/cm2
Implementation Method 2
including the deposition and annealing of these materials to form a crystalline structure
Data Source
AI summary
Capacitors and methods of forming capacitors are disclosed, and which include an inner conductive metal capacitor electrode and an outer conductive metal capacitor electrode. A capacitor dielectric region is received between the inner and the outer conductive metal capacitor electrodes and has a thickness no greater than 150 Angstroms. Various combinations of materials of thicknesses and relationships relative one another are disclosed which enables and results in the dielectric region having a dielectric constant k of at least 35 yet leakage current no greater than 1×10−7 amps/cm2 at from −1.1V to +1.1V.