Differential Vacuum Evaporation Chamber for Film Purity
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Solution Overview
Problem
Current vacuum material evaporation chambers face contamination issues due to the presence of multiple sources, leading to unintentional impurities in deposited films, which affect the properties of semi-conductive materials and other nanotechnology applications.
Innovation Solution
A vacuum material evaporation chamber design with a wall that separates the chamber into two volumes, each pumped independently, and includes recesses with individually controlled plugging means to protect sources from contamination, maintaining a pressure lower than 10−7 Torr in the second volume and using differential pumping to prevent cross-contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple material sources are placed in the same evaporation chamber, then the versatility and productivity of the chamber is improved, but cross-contamination between sources occurs leading to film impurity
Solution Approach 1:
The evaporation chamber is divided into multiple independently pumped volumes using partition walls. Each volume contains specific material sources and is pumped by dedicated pumping units, preventing cross-contamination while allowing multiple sources to operate simultaneously in different volumes.
Solution Approach 2:
Partition walls with controlled access (such as valves or masks) act as intermediaries between different source volumes. These intermediaries allow isolation of contamination-prone areas while maintaining vacuum integrity and enabling selective access to specific sources.
2Productivity
If storage panels with liquid nitrogen circulation are placed near material sources to condense gas, then gas condensation is improved, but cross-contamination from solid sources by gas remains
Solution Approach 1:
The chamber is segmented into separate volumes for gas condensation and material deposition. The storage panels are placed in dedicated volumes with independent pumping, isolating them from the material source volumes to prevent cross-contamination while maintaining effective gas condensation.
3Manufacturing precision
If individual masks are placed before unused sources to prevent contamination, then source protection is improved, but device complexity increases
Solution Approach 1:
Instead of using individual masks for each source, the chamber is divided into separately pumped volumes. This segmentation approach provides source protection through volume isolation rather than requiring complex individual masking components for each source.
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 design effectively reduces contamination, ensuring the growth of pure layers on substrates by isolating sources and maintaining a high vacuum environment, thereby improving the purity and properties of deposited films.
Implementation Method 1
a first pumping unit (13) to pump said chamber and sources of material (1), and a second pumping unit (24) to pump said second volume (22)
Implementation Method 2
a wall (23) liable to provide total or partial vacuum tightness, delineates within the vacuum chamber (10) a first volume (25) pumped by said first pumping unit (13) and a second volume (22) pumped by a second pumping unit (24)
Implementation Method 3
These sources 1 are used alternately relative to piled layers to be formed... the most current one being evaporation from a cell containing a crucible heated by Joule effect
Implementation Method 4
Molecular beam epitaxy enables to obtain, in particular for semi-conductors, a growth of doped-controlled layers... by the transport of the material, containing the elements making up the layer to form, up to a substrate, metallic or semi-conductive, where it is adsorbed
Implementation Method 5
said wall includes recesses, each recess (26) being centred on the main axis (18) of one of the sources of material (17) having a main axis (18), and the chamber contains means (27) for plugging or clearing each of said recesses (26)
Data Source
AI summary
The invention concerns a material evaporation chamber including a vacuum chamber (10), a first pumping unit (13) to pump said chamber and sources of material. According to the invention, a wall (23) liable to provide total or partial vacuum tightness, delineates within this chamber a first volume (25) and a second volume (22). Certain sources of material (17) having a main axis (18) are placed in the second volume (22). This second volume (22) is pumped by a second pumping unit (24). The wall (23) includes recesses (26) which are each centered on the main axis (18) of one of the sources of material (17). The evaporation chamber also comprises means (27) for plugging or clearing each of said recesses (26), said means (27) being controlled individually to protect the sources of material (17) having a main axis (18) unused.