Laser Heating Coating Apparatus for Stoichiometric Control
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Solution Overview
Problem
Current coating methods, such as MBE and PLD, face limitations in achieving high stoichiometric control and scalability for materials like oxides and nitrides, particularly under corrosive atmospheres, where high pressures are required, and struggle with modulated doping and purity control.
Innovation Solution
A coating apparatus utilizing a continuous laser beam for thermal evaporation of source materials below the plasma generation threshold, allowing for precise control of the coating atmosphere and stoichiometry, with a process chamber designed for high vacuum and ultrahigh vacuum conditions, enabling the deposition of materials like oxides and nitrides with modulated doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electric heating is used for thermal evaporation and sublimation of source materials, then high stoichiometric control and purity can be achieved, but electrical components are exposed to corrosive gases and may fail at higher pressures
Solution Approach 1:
The patent removes electrical heating components from the process volume by replacing them with laser heating. The laser beam is introduced through a window in the chamber wall, allowing thermal evaporation and sublimation of source materials without any electrical components being exposed to the corrosive coating atmosphere. This extraction of electrical components eliminates the reliability problem while maintaining stoichiometric control through precise laser power regulation.
Solution Approach 2:
The patent substitutes the mechanical/electrical heating system with an optical system (laser). Instead of using electrical resistance heating that requires electrical components in the process volume, the invention uses a laser beam to provide the necessary thermal energy for material evaporation and sublimation. This substitution allows operation at higher pressures in corrosive atmospheres without compromising component reliability.
2Adaptability or versatility
If high pressure coating atmosphere is used for corrosive materials like oxides and nitrides, then material deposition is enabled, but electrical components are corroded and may fail
Solution Approach 1:
The patent extracts electrical components from the high-pressure corrosive environment by using laser heating through a chamber window. This allows the system to operate at higher pressures suitable for depositing oxides and nitrides without exposing electrical heating elements to corrosive gases that would cause failure.
Solution Approach 2:
The invention replaces the electrical heating mechanism with optical laser heating, enabling the system to withstand high-pressure corrosive atmospheres. The laser beam passes through a transparent window into the process volume, providing thermal energy without requiring any electrical components to be present in the corrosive environment.
3Speed
If pulsed laser deposition is used for high kinetic energy source material, then deposition is achieved, but plasma generation occurs which may affect stoichiometry
Solution Approach 1:
The patent employs pulsed laser deposition where the laser beam is delivered in controlled pulses rather than continuously. This periodic action allows source material to be heated and evaporated with high kinetic energy for effective deposition, while the pulsed nature prevents sustained plasma generation that would compromise stoichiometric control. The pulse duration and frequency are optimized to achieve desired deposition rates without excessive plasma effects.
Solution Approach 2:
The invention carefully controls laser parameters including pulse duration, repetition frequency, and energy density to achieve the optimal balance between source material kinetic energy and plasma generation. By adjusting these parameters, the system maintains high deposition efficiency while preventing plasma conditions that would disrupt stoichiometry, particularly for multi-element materials.
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 provides high stoichiometric control and purity of the deposited layer materials, enabling the production of complex oxides and nitrides with variable doping under a wide range of pressures, including corrosive conditions, while avoiding electrical components in the process volume.
Implementation Method 1
a source heating laser, wherein the source heating laser is configured to provide a continuous or at least substantially continuous separate beam of laser light for each of the at least one elemental source materials
Implementation Method 2
for thermally evaporating and/or sublimating each of the elemental source materials below a plasma generation threshold
Implementation Method 3
for thermally evaporating and/or sublimating each of the elemental source materials below a plasma generation threshold
Implementation Method 4
the source heating laser is configured to provide a continuous or at least substantially continuous separate beam of laser light for each of the at least one elemental source materials
Implementation Method 5
wherein the source holder and the substrate holder are further arranged relative to one another such that thermally evaporated and/or sublimated source material can be deposited on the substrate for an at least partial formation of the layer material of the material layer
Data Source
AI summary
The present invention refers to a coating apparatus for coating a substrate of a substrate material with at least one material layer of a layer material, said coating apparatus comprising a process chamber having a process volume for receiving a substrate holder for arranging the substrate, wherein the substrate holder is arranged in a fixed position in the process volume such that the substrate holder can furthermore be provided rotatable and/or movable essentially in a plane normal to the deposition direction as a whole, wherein the process chamber has a chamber wall for at least substantially completely enclosing the process volume; a gas system connected in a fluid-communicating manner to the process volume for generating a coating atmosphere in the process volume; and a source holder arranged in the process volume and providing at least one source material.