SiC-on-Carrier Nitride Structures Using PEC Etch-Stop Layers
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Solution Overview
Problem
Current techniques for forming silicon carbide and group III nitride structures face challenges such as non-uniform films, material damage, and high optical losses due to dislocations and residual doping, particularly when grown on silicon substrates, limiting their quality and suitability for photonic applications.
Innovation Solution
A method involving photo-electrochemical etching is used to form silicon carbide device layers on a carrier substrate, with a doped layer acting as an etch-stop, allowing for selective removal of the doped layer while preserving the silicon carbide device layer, and bonding these layers to a carrier substrate using oxide layers to achieve uniformity and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silicon carbide and group III nitride structures are formed on silicon substrates using conventional techniques, then the structures can be fabricated, but the film quality deteriorates with non-uniformity, material damage, and high optical losses due to dislocations and residual doping
Solution Approach 1:
The patent segments the silicon carbide structure into multiple distinct layers: a silicon substrate, a buffer layer, an intermediate layer, and a device layer. This segmentation allows each layer to serve specific functions - the buffer layer manages lattice mismatch, the intermediate layer controls doping, and the device layer provides high-quality material for photonic applications, thereby resolving the contradiction between manufacturability and optical quality
Solution Approach 2:
The patent introduces an intermediate layer between the silicon substrate and the group III nitride layers. This intermediate layer acts as a mediator that manages the lattice mismatch and reduces dislocation propagation from the silicon substrate to the active device layers, thereby improving film uniformity and reducing optical losses while maintaining the ability to fabricate devices
2Productivity
If conventional growth techniques are used on silicon substrates, then fabrication can proceed, but dislocations and residual doping increase causing high optical losses
Solution Approach 1:
The patent performs preliminary actions during the growth process by carefully controlling the doping concentration and layer structure before the actual device fabrication. The buffer and intermediate layers are grown with specific doping profiles that prevent dislocation formation and residual doping in the subsequent device layers, ensuring high optical performance while maintaining fabrication capability
Solution Approach 2:
The patent changes key growth parameters including doping concentration, layer thickness, and growth temperature to optimize the structure. By adjusting these parameters, the patent achieves low dislocation density and minimal residual doping in the device layers while maintaining practical fabrication conditions, thus resolving the contradiction between productivity and optical performance
3Ease of manufacture
If thin-film devices are formed using silicon carbide and group III nitrides, then the devices can be fabricated, but the quality is lower compared to other materials such as silicon
Solution Approach 1:
The patent applies local quality by creating regions with different doping concentrations and layer compositions tailored to specific functions. The device layer is grown with optimized local properties including controlled doping and thickness to achieve high material quality for photonic devices, while other layers are optimized for their respective functions, thereby improving overall device quality without compromising ease of manufacture
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, enabling the fabrication of photonic devices like optical waveguides and resonators with improved performance and scalability.
Implementation Method 1
The doped layer has a doping level such that the doped layer is etched using a photo-electrochemical etching process and other portions of the silicon carbide substrate remain unetched
Implementation Method 2
The first oxide layer is bonded to a second oxide layer on a carrier substrate to form an oxide layer located between the carrier substrate and the set of group III nitride layers
Data Source
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AI summary
A method, apparatus, and system for forming a semiconductor structure. A first oxide layer (402, 912) located on a set of group III nitride layers (200, 908, 910, 1308, 1310, 1606, 1806, 2006, 2106, 2210, 2212, 2310, 2312) formed on a silicon carbide substrate (100, 1003) is bonded to a first oxide layer (504, 1002) located on a carrier substrate (500, 1000, 1314, 1602, 1802, 2002, 2102, 2202, 2302, 2402) to form an oxide layer (600, 1100, 1312, 1604, 1804, 2004, 2104, 2204, 2304) located between the carrier substrate (500, 1000, 1314, 1602, 1802, 2002, 2102, 2202, 2302, 2402) and the set of group III nitride layers (200, 908, 910, 1308, 1310, 1606, 1806, 2006, 2106, 2210, 2212, 2310, 2312). The silicon carbide substrate (100, 1003) has a doped layer (106, 904, 1302). The silicon carbide substrate (100, 1003) having the doped layer (106, 904, 1302) is etched using a photo-electrochemical etching process, wherein a doping level of the doped layer (106, 904, 1302) is such that the doped layer (106, 904, 1302) is removed and a silicon carbide layer in the silicon carbide substrate (100, 1003) remains unetched. The semiconductor structure is formed using the silicon carbide layer and the set of group III nitride layers (200, 908, 910, 1308, 1310, 1606, 1806, 2006, 2106, 2210, 2212, 2310, 2312).