GaN Chip Transfer Using Dual Sacrificial Layers for Thermal Integration
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Solution Overview
Problem
The high cost and limited flexibility of GaN-based microwave power devices due to the expensive SiC substrate and the complexity of transferring GaN heterostructures from SiC substrates to other substrates with high thermal conductivity, which affects the output power density and crystal quality.
Innovation Solution
A method involving the use of a sacrificial 'sandwich' structure with Nb2N and Ta2N layers between the GaN functional material and the SiC substrate, allowing for the transfer of GaN devices to substrates with high thermal conductivity, reducing integration difficulties and extending application range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If SiC substrate is used for GaN heterostructure growth, then thermal conductivity and crystal quality are improved, but cost increases significantly
Solution Approach 1:
The patent segments the GaN heterostructure from the SiC substrate by introducing sacrificial layers (AlN or GaN) at the interface. This allows the GaN layer to be grown on SiC for optimal crystal quality, then separated and transferred to a different substrate for final device assembly, effectively decoupling the growth phase from the final application phase.
Solution Approach 2:
The patent introduces sacrificial layers (AlN or GaN) as intermediary elements between the SiC substrate and the GaN heterostructure. These sacrificial layers enable controlled separation through selective etching, allowing the GaN device to be transferred from the expensive SiC substrate to a cheaper target substrate while maintaining crystal quality.
2Reliability
If stripping technology is used to transfer GaN heterostructure from SiC substrate, then cost is reduced, but process complexity increases
Solution Approach 1:
The patent extracts the GaN heterostructure from the SiC substrate by removing the sacrificial layers through selective etching. This extraction process separates the valuable GaN layer from the expensive SiC substrate, allowing transfer to a cheaper target substrate while maintaining device performance.
Solution Approach 2:
The patent utilizes parameter changes in material properties—specifically the selective etch resistance differences between the sacrificial layers (AlN/GaN) and the SiC substrate—to achieve controlled separation. By adjusting etching parameters, the sacrificial layers are removed while the SiC substrate remains intact, enabling substrate reuse.
3Productivity
If laser lift-off technology is used for stripping, then transfer efficiency is improved, but process complexity and cost increase due to excimer laser requirement
Solution Approach 1:
The patent replaces the complex laser-based mechanical system with a simpler chemical etching process. Instead of using excimer lasers to ablate the sacrificial layers, the invention employs selective chemical etchants that dissolve the AlN or GaN sacrificial layers, achieving the same transfer effect with simpler equipment and lower cost.
4Manufacturing precision
If smart-cut technology is used for thin film transfer, then transfer precision is improved, but wafer bonding requirements become more stringent
Solution Approach 1:
The patent extracts the GaN heterostructure from the SiC substrate through selective removal of sacrificial layers, avoiding the need for complex wafer bonding processes required by smart-cut technology. The GaN layer is released and transferred without requiring high-precision bonding interfaces between donor and recipient wafers.
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 simplifies the heterogeneous integration of GaN devices, improves thermal management, and enhances the performance of radio frequency power devices and flexible electronic devices by reducing the complexity and cost of substrate transfer.
Implementation Method 1
removing the Nb2N sacrificial layer and the Ta2N sacrificial layer
Implementation Method 2
bonding the GaN wafer with a first surface of a temporary carrier
Data Source
AI summary
The present application discloses a method, a system, a device, and a storage medium for fabricating a GaN chip. The method includes: growing a Nb2N sacrificial layer on an original substrate, and growing a GaN insertion layer on the Nb2N sacrificial layer; growing a Ta2N sacrificial layer on the GaN insertion layer, and growing a semiconductor layer on the Ta2N sacrificial layer to form a GaN wafer; bonding the GaN wafer with a first surface of a temporary carrier, and removing the Nb2N sacrificial layer and the Ta2N sacrificial layer; and transferring remaining material after removal of the Nb2N sacrificial layer and the Ta2N sacrificial layer to a target substrate, and removing the temporary carrier from the remaining material to form the GaN chip.