Rotating Drum Gas Delivery for Gradient Atomic Layer Deposition
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Solution Overview
Problem
Atomic layer deposition methods are time-consuming for achieving layer thicknesses greater than 10 nanometers and lack the ability to deposit films with composition gradients, which are desirable for optimizing electrical, optical, and interfacial properties in devices.
Innovation Solution
A method involving a rotatable drum with gas feed channels and circumferential grooves that allow for varying precursor gas compositions, enabling the deposition of a stack of atomic layers with a gradient composition by controlling the precursor gas flow and reaction on the substrate during rotation, thereby avoiding convective mixing and allowing for continuous or reciprocating motion of the deposition head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If atomic layer deposition is used to deposit thick layers (>10 nm), then the desired layer thickness is achieved, but the deposition process becomes time-consuming
Solution Approach 1:
The precursor-gas supply is segmented into multiple zones along the circumferential direction, with each zone providing a different precursor gas composition. This allows simultaneous deposition of multiple atomic layers with different compositions in a single continuous rotation, achieving thick gradient films without the time penalty of sequential deposition
Solution Approach 2:
The drum rotates continuously to supply precursor gases, eliminating the need for repeated stopping and starting that occurs in conventional batch processing. The continuous rotation enables uninterrupted deposition of thick layers while maintaining precise compositional control through the zoned gas supply system
2Manufacturing precision
If conventional atomic layer deposition is used, then monolayer precision is achieved, but the capability to deposit films with composition gradients is lost
Solution Approach 1:
Different zones of the drum surface are assigned different precursor gas compositions, creating local quality variations along the circumferential direction. As the drum rotates, each zone deposits atomic layers with its specific composition, resulting in a film with a controlled composition gradient that maintains monolayer precision while achieving compositional versatility
Solution Approach 2:
The composition control is extended from a single-point precision approach to a spatial distribution along the circumferential dimension. The zoned gas supply system adds a spatial dimension to composition control, enabling gradient films while maintaining the atomic-layer precision characteristic of ALD
3Productivity
If multiple precursor gases are supplied simultaneously, then deposition rate is improved, but convective mixing between gas zones occurs
Solution Approach 1:
The gas supply is divided into distinct zoned regions separated by physical barriers on the drum surface. Each zone maintains its unique precursor gas composition without convective mixing, while the continuous rotation ensures all zones contribute to deposition, achieving both high deposition rate and composition stability
Solution Approach 2:
The drum surface acts as an intermediary that physically separates different precursor gas zones while enabling their coordinated delivery to the substrate. The zoned structure on the drum surface prevents direct mixing between gas streams, maintaining composition stability while allowing simultaneous deposition from multiple zones
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 the efficient deposition of thick layers with gradient composition profiles, potentially increasing deposition rates and achieving more even layer deposition without seams, while allowing for flexible substrate use and precise control over precursor concentrations.
Implementation Method 1
the drum being rotatable with respect to a sealing piece that receives gas from a gas source
Implementation Method 2
the other of the drum or sealing piece comprises one or more circumferential grooves in its surface sealed by the one of the drum or sealing piece thereby preventing a fluid flowpath in radial direction and leaving a fluid flow path in circumferential direction
Implementation Method 3
At least one sealed groove is provided with one or more separations separating adjacent zones of process gas feeds in the sealed groove, thus allowing zones to provide for mutually differing process gas compositions
Implementation Method 4
having the precursor gas react near, e.g. on, the substrate so as to form an atomic layer
Implementation Method 5
A first one of these self-limited process steps comprises application of a precursor gas on a substrate's surface
Data Source
AI summary
A method of depositing an atomic layer on a substrate comprises supplying a precursor gas from a precursor-gas supply comprised in a drum; the drum being rotatable with respect to a sealing piece that receives gas from a gas source. One of the drum or sealing piece comprising one or more gas feed channels in fluid connection with the precursor-gas supply and the other of the drum or sealing piece comprises one or more circumferential grooves in its surface sealed by the one of the drum or sealing piece thereby preventing a fluid flowpath in radial direction and leaving a fluid flow path in circumferential direction. At least one sealed groove is provided with one or more separations separating adjacent zones of process gas feeds in the sealed groove, thus allowing zones to provide for mutually differing process gas compositions to have the precursor gas react near, e.g. on, the substrate thus depositing a stack of atomic layers of a gradient composition.