Mid-Infrared Resistive Heating for Wide Bandgap Substrates
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Solution Overview
Problem
Conventional methods for heating wide bandgap (WBG) substrates in vacuum deposition processes are inefficient and require additional coatings or backing plates, leading to contamination and challenges in achieving uniform temperature profiles, especially in high vacuum environments where convection heating is absent.
Innovation Solution
Utilizing resistive heating elements made of materials like SiC and Ga2O3 that emit mid-infrared radiation matching the phonon absorption bands of WBG substrates, allowing direct radiative heating without coatings or backing plates, and employing multizone heating elements with pyrometric feedback control for uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heating methods are used for WBG substrates in vacuum deposition, then heating can be achieved, but additional coatings or backing plates are required leading to contamination and non-uniform temperature profiles
Solution Approach 1:
The patent replaces conventional mechanical contact heating methods (which require coatings or backing plates) with radiative heating using mid-infrared emitting resistive heating elements. This substitution eliminates the need for additional coatings or backing plates, thereby preventing contamination while achieving efficient and uniform heating of WBG substrates in vacuum deposition environments
Solution Approach 2:
The patent changes the heating parameter from conventional thermal conduction/convection to radiative heating in the mid-infrared wavelength range (5-40 μm). By matching the emission spectrum of the heating elements to the phonon absorption bands of WBG materials, the patent achieves direct absorption of radiant energy by the substrate without requiring intermediate coatings, thus eliminating contamination while maintaining heating efficiency
2Temperature
If conventional heating methods are used for WBG substrates, then heating can be achieved, but uniform temperature distribution is difficult to obtain
Solution Approach 1:
The patent divides the heating system into multiple independently controllable heating zones arranged in a multizone configuration. Each zone can be controlled separately to achieve uniform temperature distribution across the substrate surface, eliminating the need for complex feedback control systems while maintaining temperature uniformity
Solution Approach 2:
The patent applies different heating characteristics to different zones of the heating element array, allowing each local region to be optimized for its specific position relative to the substrate. This enables precise control of temperature distribution across the substrate surface without requiring complex overall system design
3Ease of manufacture
If mid-infrared radiative heating is used for WBG substrates, then direct heating without coatings is achieved, but the heating element material must be specifically selected
Solution Approach 1:
The patent changes the material parameter of the heating element to specifically use mid-infrared emitting materials (such as SiC, Ga2O3, or other ceramics with appropriate emissivity characteristics). This material selection enables direct radiative heating of WBG substrates without coatings, simplifying the manufacturing process while requiring specific material properties for optimal performance
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
Enables efficient, uniform, and oxidation-resistant heating of WBG substrates in high vacuum conditions, facilitating the growth of epitaxial oxide layers with improved quality and properties.
Implementation Method 1
Radiative heat emitted from the resistive heating element has a wavelength in a mid-infrared band from 5 μm to 40 μm that corresponds to a phonon absorption band of a substrate
Implementation Method 2
The radiative heat has a wavelength in a mid-infrared band from 5 μm to 40 μm that corresponds to a phonon absorption band of a substrate
Implementation Method 3
providing a resistive heater having a resistive heating element. Radiative heat is generated from the resistive heating element
Data Source
AI summary
Methods and systems of heating a substrate in a vacuum deposition process include a resistive heater having a resistive heating element. Radiative heat emitted from the resistive heating element has a wavelength in a mid-infrared band from 5 μm to 40 μm that corresponds to a phonon absorption band of the substrate. The substrate comprises a wide bandgap semiconducting material and has an uncoated surface and a deposition surface opposite the uncoated surface. The resistive heater and the substrate are positioned in a vacuum deposition chamber. The uncoated surface of the substrate is spaced apart from and faces the resistive heater.