High-Temperature Detachable SiC Temporary Substrate Transfer
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Solution Overview
Problem
Existing methods for producing composite structures with monocrystalline silicon carbide (c-SiC) on polycrystalline SiC carrier substrates are not compatible at high temperatures above 1200°C due to rapid cavity growth kinetics, leading to blistering and inadequate stiffening, which compromises the integrity of the carrier substrate.
Innovation Solution
A detachable temporary substrate comprising a semiconductor working layer, an intermediate layer with a thickness less than 20 nm, and a carrier substrate, with gaseous species atoms distributed to facilitate detachment at temperatures above 1000°C, allowing transfer of the working layer to a receiver substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal carrier substrate is used with a buried weakened plane in c-SiC donor substrate, then a composite structure with thin c-SiC layer can be produced, but at temperatures above 1200°C the cavity growth kinetics become faster than p-SiC layer growth kinetics causing blistering and deformation
Solution Approach 1:
The patent introduces an intermediate layer between the c-SiC working layer and the carrier substrate that acts as a mediator. This intermediate layer has specific properties that allow it to accommodate thermal expansion differences and prevent direct thermal stress transmission, thereby avoiding blistering and deformation at high temperatures while still enabling thin layer transfer.
Solution Approach 2:
The patent modifies the thermal and mechanical parameters of the carrier substrate system by using a polynomial SiC layer instead of metal, and by controlling the thickness and properties of the intermediate layer. These parameter changes enable the system to maintain structural integrity at temperatures above 1200°C while preserving the thin layer transfer capability.
2Reliability
If direct bonding is used to join c-SiC thin layer to carrier substrate, then vertical electrical conduction is achieved, but the process is incompatible with p-SiC carrier substrates requiring deposition temperatures above 1200°C
Solution Approach 1:
The intermediate layer serves as a mediator that enables compatibility between the c-SiC working layer and p-SiC carrier substrate. It allows the system to withstand the high deposition temperatures required for p-SiC while maintaining the electrical conduction pathway through the bonded interface.
Solution Approach 2:
The patent creates a composite structure consisting of multiple layers (c-SiC working layer, intermediate layer, polynomial SiC carrier substrate) where each material is selected for its specific properties. This composite approach enables both electrical conduction and compatibility with high-temperature p-SiC processing.
3Strength
If the thickness of the intermediate layer is increased to improve bonding strength, then mechanical strength is enhanced, but detachment at high temperature becomes more difficult and may cause working layer damage
Solution Approach 1:
The patent optimizes the thickness parameter of the intermediate layer to a specific range that balances bonding strength and detachability. By precisely controlling this parameter, the system achieves sufficient mechanical strength during processing while maintaining the ability to detach cleanly at high temperatures without damaging the working layer.
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 the transfer of high-temperature compatible materials like silicon carbide and gallium nitride to a receiver substrate while maintaining the integrity and purity of the working layer, suitable for vertical electrical conduction in power devices.
Implementation Method 1
the atoms being intended to diffuse to a detachment interface when the temporary substrate is subjected to a temperature higher than or equal to the detachment temperature
Implementation Method 2
a bonding interface located in the intermediate layer or adjacent thereto
Data Source
AI summary
A temporary substrate, which is detachable at a detachment temperature higher than 1000° C. comprises:a semiconductor working layer extending along a main plane,a carrier substrate,an intermediate layer having a thickness less than 20 nm arranged between the working layer and the carrier substrate,a bonding interface located in or adjacent the intermediate layer,gaseous atomic species distributed according to a concentration profile along the axis normal to the main plane, the atoms remaining trapped in the intermediate layer and/or in an adjacent layer of the carrier substrate with a thickness less than or equal to 10 nm and/or in an adjacent sublayer of the working layer with a thickness less than or equal to 10 nm when the temporary substrate is subjected to a temperature lower than the detachment temperature.