Semiconductor Island Transfer via Si(111) Etching for Reliable Bonding
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Solution Overview
Problem
Existing methods for manufacturing semiconductor thin film devices face challenges in isolating components, transferring semiconductor layers without difficulty, and achieving reliable bonding and low-resistance contacts, particularly with highly doped nitride semiconductor and SiC materials.
Innovation Solution
A method involving forming a buffer layer and a single crystal semiconductor layer on an Si (111) substrate, creating an island structure, coating it, etching along the Si (111) plane to release the island, and bonding it to a second substrate with a released surface for direct contact, allowing for intermolecular force bonding and low-resistance ohmic contact formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous Si layer and BP buffer layer are formed on an Si substrate, then a GaN/AlGaN layer can be formed, but component isolation becomes difficult and device transfer to another substrate is problematic
Solution Approach 1:
The invention divides the semiconductor layer into isolated island structures on the Si substrate, with each island containing a complete device structure. This segmentation enables independent handling and transfer of individual device islands to the target substrate, solving the component isolation problem while maintaining bonding reliability.
Solution Approach 2:
The invention extracts the active semiconductor device structure (GaN/AlGaN layer with buffer layer) from the Si substrate as separate island structures. This extraction allows the device islands to be transferred to the target substrate without the entire Si substrate, simplifying the transfer process and enabling reliable bonding.
2Reliability
If a Ti/Al/Pt electrode is formed on the uppermost layer, then electrical contact is achieved, but highly doped nitride semiconductor and SiC still cannot achieve high activation for low-resistance contacts
Solution Approach 1:
The invention changes the doping parameter of the semiconductor layer to create highly doped regions (e.g., n-type doping with concentration ≥1×10^19 atoms/cm³) in the island structures. This parameter change enables high activation efficiency and formation of low-resistance ohmic contacts, achieving reliable electrical contact without requiring complex multi-layer electrode structures.
3Ease of manufacture
If the buffer layer is removed by lapping after transferring the structure, then the structure can be bonded to the second substrate, but the process becomes complex and Al/Ti layer bonding becomes unreliable under high temperature heating
Solution Approach 1:
The invention inverts the conventional process sequence: instead of forming the complete structure on Si substrate and then removing the buffer layer for bonding, the method forms island structures that are directly transferable. The buffer layer removal is performed in advance during island formation, allowing direct bonding of the island structures to the target substrate without high-temperature heating, thus simplifying the process and ensuring bonding reliability.
4Adaptability or versatility
If components are formed after bonding the semiconductor layer to another substrate, then device integration is achieved, but high temperature heating processes prevent reliable bonding
Solution Approach 1:
The invention performs preliminary actions of forming the complete island structure with buffer layer on the Si substrate before transfer. All necessary layer formations and buffer layer preparations are completed in advance, allowing the island structures to be transferred and bonded to the target substrate in a low-temperature process, thereby enabling subsequent high-temperature device fabrication processes without compromising bonding reliability.
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 manufacturing process, achieves excellent flatness for bonding, enables high-doping of the release surface, and facilitates low-resistance ohmic contacts, allowing for effective bonding and reuse of the Si (111) substrate.
Implementation Method 1
forming a coating layer on a surface of the island; etching the Si (111) substrate along an Si (111) plane of the Si (111) substrate to release the island from the Si (111) substrate, the coating layer serving as a mask during etching
Implementation Method 2
bonding the released island to a second substrate with a released surface of the released island in direct contact with the second substrate
Implementation Method 3
etching the Si (111) substrate along an Si (111) plane of the Si (111) substrate to release the island from the Si (111) substrate
Data Source
AI summary
A method for manufacturing a semiconductor thin film device includes: forming a buffer layer on an Si (111) substrate and a single crystal semiconductor layer on the buffer layer; forming an island including the semiconductor layer, buffer layer, and a portion of the substrate; forming a coating layer on the island; etching the substrate along its Si (111) plane to release the island from the substrate, the coating layer serving as a mask; and bonding the released island to another substrate, a released surface of the released island contacting the another substrate. A semiconductor device includes a single crystal semiconductor layer other than Si, which has a semiconductor device formed on a front surface of an Si (111) layer lying in a (111) plane. The layer is bonded to another substrate with a back surface contacting the another substrate or a bonding layer formed on the another substrate.