ALD Dielectric Deposition for Capacitor Composition Control
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Solution Overview
Problem
Existing methods for forming dielectric materials over substrates, such as those used in capacitor fabrication, face challenges in precisely controlling the composition and quantity of multiple metal/metalloid components, which affects the dielectric properties and leakage current.
Innovation Solution
A method involving an ALD-type sequence where a substrate is sequentially contacted with first and second precursors, each with different central atoms and ligands, followed by a reactant to form a reaction product, allowing for precise control of the deposited material's composition and quantity through steric effects and ligand interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD or ALD methods are used to deposit dielectric materials, then the deposition process can be performed, but precise control of multiple metal/metalloid composition and quantity is difficult to achieve
Solution Approach 1:
The deposition process is segmented into multiple sequential ALD cycles, each depositing a specific metal component with controlled quantity. The dielectric layer is formed by segmenting the deposition into distinct stages: first depositing the majority metal (Hf or Zr), then sequentially adding minority metals (Al, Si) in separate ALD cycles, allowing precise compositional control through process segmentation
Solution Approach 2:
The invention employs parameter changes by varying the precursor materials, deposition temperature, and cycle numbers in sequential ALD steps. By changing these parameters between different metal deposition stages, the process achieves precise control over the multi-metal composition while managing process complexity through systematic parameter variation
2Reliability
If the majority metal component is increased to provide high dielectric constant, then the dielectric property is improved, but leakage current increases due to undesired characteristics
Solution Approach 1:
The invention creates a composite dielectric material combining multiple metals (Hf, Zr, Al, Si) in specific ratios. The majority metal (Hf or Zr) provides the high dielectric constant, while the minority metals (Al, Si) are incorporated in controlled quantities to suppress leakage current. This composite approach allows simultaneous optimization of dielectric property and reduction of harmful leakage characteristics
Solution Approach 2:
The deposition process applies local quality by creating regions with different metal compositions within the dielectric layer. Through sequential ALD deposition, specific areas or layers within the dielectric can be tailored with optimized metal ratios, allowing the majority metal to provide dielectric constant while minority metals locally address leakage current issues
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 approach enables precise control of the deposited material's composition and properties, impacting crystallinity, film stress, dielectric, and leakage current properties, thereby improving the performance of dielectric layers and capacitors.
Implementation Method 1
an outermost surface of a substrate is contacted with a first precursor to chemisorb a first species onto the outermost surface from the first precursor
Implementation Method 2
the outermost surface is contacted with a second precursor to chemisorb a second species different from the first species onto the outermost surface from the second precursor
Implementation Method 3
the chemisorbed first species and the chemisorbed second species are contacted with a reactant which reacts with the first species and with the second species to form a reaction product
Data Source
AI summary
A method of forming a material over a substrate includes performing at least one iteration of the following temporally separated ALD-type sequence. First, an outermost surface of a substrate is contacted with a first precursor to chemisorb a first species onto the outermost surface from the first precursor. Second, the outermost surface is contacted with a second precursor to chemisorb a second species different from the first species onto the outermost surface from the second precursor. The first and second precursors include ligands and different central atoms. At least one of the first and second precursors includes at least two different composition ligands. The two different composition ligands are polyatomic or a lone halogen. Third, the chemisorbed first species and the chemisorbed second species are contacted with a reactant which reacts with the first species and with the second species to form a reaction product new outermost surface of the substrate.