Silicon Carbide and Nitride Structures on Substrate
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Solution Overview
Problem
Current methods for fabricating silicon carbide and group III nitride structures face challenges such as non-uniformity, material damage, and high optical losses due to dislocations and interfacial defects, particularly when grown on silicon substrates, limiting their quality and suitability for photonic applications.
Innovation Solution
A method involving a photo-electrochemical etching process is used to form semiconductor structures with silicon carbide and group III nitride layers, where a doped layer is selectively etched to preserve the underlying silicon carbide layer, reducing defects and achieving uniformity, and these layers are bonded to a carrier substrate using oxide layers to enhance film quality and reduce strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon carbide and group III nitride structures are grown on silicon substrates, then manufacturing capability is improved, but manufacturing precision deteriorates due to non-uniformity and material damage
Solution Approach 1:
A sacrificial silicon carbide layer is introduced as an intermediary between the silicon substrate and the device layers. This sacrificial layer mediates the lattice mismatch and thermal expansion differences, enabling high-quality growth of group III nitride and silicon carbide device layers while preventing direct contact between the incompatible silicon substrate and the sensitive device structures.
Solution Approach 2:
The structure is segmented into distinct functional layers: a silicon substrate, a sacrificial silicon carbide layer, and device layers (group III nitride and silicon carbide). This segmentation allows each layer to be optimized independently - the sacrificial layer handles substrate compatibility while the device layers achieve high precision and uniformity.
2Ease of manufacture
If silicon carbide and group III nitride structures are grown on silicon substrates, then manufacturing capability is improved, but reliability deteriorates due to dislocations and interfacial defects
Solution Approach 1:
The sacrificial silicon carbide layer acts as a buffer that prevents dislocation propagation from the silicon substrate to the device layers. By isolating the device structures from the problematic substrate interface, the sacrificial layer eliminates the source of interfacial defects and maintains high optical quality in the final device.
Solution Approach 2:
The harmful interface between silicon substrate and silicon carbide/device layers is extracted and replaced with a sacrificial silicon carbide layer. This removes the source of lattice mismatch and thermal stress that would otherwise create dislocations and interfacial defects in the device structure.
3Adaptability or versatility
If thin-film devices are fabricated using silicon carbide and group III nitrides, then device functionality is achieved, but ease of manufacture deteriorates due to fabrication difficulty
Solution Approach 1:
The sacrificial silicon carbide layer is prepared in advance before device fabrication. This preliminary action creates a pre-conditioned substrate that is compatible with subsequent thin-film growth processes, making the actual device fabrication easier and more reliable while maintaining full device functionality.
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 results in high-quality, uniform silicon carbide and group III nitride thin-films with reduced optical losses, suitable for photonic devices, enabling the fabrication of structures like optical waveguides and resonators with improved performance.
Implementation Method 1
A method involving a photo-electrochemical etching process is used to form semiconductor structures with silicon carbide and group III nitride layers, where a doped layer is selectively etched to preserve the underlying silicon carbide layer
Implementation Method 2
these layers are bonded to a carrier substrate using oxide layers to enhance film quality and reduce strain
Data Source
AI summary
A semiconductor structure comprises a substrate; an oxide layer on the substrate; a set of group III nitride layers on the oxide layer; and a set of silicon carbide layers located on the set of group III nitride layers.