Pulsed Laser Deposition Velocity Filter Partition Wall
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Solution Overview
Problem
In pulsed laser deposition devices, undesired particles from the target material can contaminate the substrate layer due to incomplete filtration by the velocity filter, as these particles may float between the filter and the target, potentially being redeposited with subsequent plasma plumes.
Innovation Solution
A partition wall is introduced in the reactor housing, enclosing the rotating velocity filter, with a gap between the filter's circumference and the wall's edge of 10mm to 30mm, creating a gas flow that drags floating particles into the pump outlet, preventing contamination. Additional features like recesses and radially extending ribs enhance particle removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a velocity filter is used to filter undesired particles from the plasma plume, then particle contamination is reduced, but floating particles between the filter and target can still contaminate the substrate
Solution Approach 1:
The device is divided into two separate chambers by a partition wall: a target chamber containing the target and velocity filter, and a substrate chamber containing the substrate. This segmentation prevents floating particles in the target chamber from reaching the substrate, while the velocity filter continues to filter the plasma plume effectively.
Solution Approach 2:
A partition wall acts as an intermediary barrier between the target chamber and substrate chamber. It physically separates the two spaces, preventing direct contact between floating particles and the substrate, while allowing controlled plasma plume transmission through the velocity filter.
2Manufacturing precision
If the velocity filter rotates to filter particles, then filtration efficiency improves, but the structure becomes more complex
Solution Approach 1:
The filtering function is segmented into two components: the velocity filter for active particle selection through rotation, and the partition wall for passive physical separation. This division allows each component to perform its specific function efficiently without unnecessary complexity.
Solution Approach 2:
The partition wall serves as a simple intermediary structure that provides physical separation without requiring complex mechanisms. It complements the velocity filter by handling the separation of floating particles, allowing the velocity filter to focus on filtering the plasma plume.
3Volume of stationary object
If the distance between the velocity filter and partition wall is too small, then device size is reduced, but gas flow cannot effectively remove floating particles
Solution Approach 1:
The gap between the velocity filter and partition wall is optimized to a specific range (10-30mm) to create appropriate gas flow characteristics. This local dimensional specification ensures sufficient gas flow velocity to carry floating particles to the pump outlet while maintaining compact overall device size.
Solution Approach 2:
The distance parameter between the velocity filter and partition wall is carefully controlled within a specific range (10-30mm). This parameter optimization balances two competing requirements: maintaining compact device size while ensuring sufficient gas flow for effective particle removal.
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
The solution effectively reduces the number of undesired particles on the substrate, improving the quality of the deposited layer by ensuring that floating particles are consistently removed with the gas flow, maintaining a balance between filtration efficiency and particle distribution across the substrate.
Implementation Method 1
a gas flow over the rotating body along the full circumference thereof towards the pump outlet is obtained. As a result the gas flow will drag floating undesired particles along and into the pump outlet
Implementation Method 2
a pulsed laser directed through a window arranged in the reactor housing onto the target at a target spot for generating a plasma plume of target material
Implementation Method 3
By controlling the speed of the rotating body and synchronizing it with the pulsed laser, it is possible to let the plasma plume pass the velocity filter via the filter passage opening, while the slower, undesired particles are blocked by the rotating body
Data Source
Figure 1~2
AI summary
The invention relates to a device for pulsed laser deposition, a substrate with a substrate surface and a target with a target surface, which device comprises: - a reactor housing having a pump inlet and a pump outlet for providing a desired gas atmosphere in the reactor housing; - a substrate holder arranged in the reactor housing for holding the substrate; - a target holder arranged in the reactor housing for holding the target with the target surface facing the substrate surface of the substrate; - a velocity filter arranged in the reactor housing and between the substrate holder and the target holder, which velocity filter comprises a rotating, generally disc-shaped body with a rotation axis and with at least one filter passage opening extending from one axial surface facing the target holder to the other axial surface of the rotating body facing the substrate holder; - a pulsed laser directed through a window arranged in the reactor housing onto the target at a target spot for generating a plasma plume of target material, wherein the surface of the target at the target spot faces the substrate surface, wherein the path of the at least one filter passage opening coincides with the target spot when viewed in a direction perpendicular to the surface of the target at the target spot; and - a partition wall arranged in the reactor housing, which partition wall extends between the substrate holder and the target holder, wherein the rotating, generally disc-shaped body of the velocity filter is arranged in an opening in the partition wall, wherein the circumference of the rotating body is enclosed by the edge of the opening in the partition wall and and wherein the distance between the edge of the opening and the circumference of the rotating body in radial direction is between 10mm and 30mm.