Transfer van Grafeen met behulp van Technologisch Compatibele Halfgeleiderprocessen: Baanbrekende Technieken voor de Integratie van Grafeen in Moderne Elektronica
Year: 2025
Type: dissertation
Abstract: Graphene, a single-layer hexagonal lattice of carbon atoms, exhibits extraordinary electrical, mechanical, and optical properties, positioning it as a transformative material for next-generation semiconductor, electronic, and optoelectronic technologies. Particularly, in response to the unprecedented demand for data transmission, graphene-based optoelectronic devices effectively translate electrical signals into photonic pulses, addressing critical limitations such as power consumption and bandwidth constraints. Its exceptional carrier mobility and broadband absorption capabilities make graphene particularly suitable for advanced applications, including photodetectors and modulators. Nevertheless, the practical implementation of graphene in electronic applications requires the seamless integration of high-quality graphene films into the established semiconductor manufacturing infrastructure. However, significant technological hurdles persist in producing large-scale, high-quality graphene compatible with existing semiconductor foundry technologies. This thesis systematically addresses these challenges by developing scalable, technology-compatible synthesis and transfer techniques, iteratively exploring both synthesis and transfer methodologies. Firstly, the thesis investigates the feasibility of graphene transfer using wafer bonding technology-compatible carriers. An under-etching transfer methodology employing a semi-rigid glass carrier is developed, successfully demonstrating enhanced handling of graphene during transfer. This process highlights critical challenges in releasing graphene grown on epitaxial metal thin films deposited onto sapphire substrates. Subsequently, the concept of incorporating a sacrificial release layer between the metal thin film and sapphire substrate is explored, utilizing an interfacial carbon layer fabricated via chemical vapor deposition (CVD). A detailed examination of the growth mechanisms for this interfacial carbon layer reveals challenges in maintaining uniformity across large-scale substrates. Despite these uniformity challenges, the concept successfully demonstrates its potential to facilitate wafer-scale graphene release, proving its viability as a graphene release strategy. Building upon these validated concepts, the thesis introduces an innovative laser-assisted graphene transfer method utilizing an inorganic epitaxial titanium nitride (TiN) interlayer. Comprehensive studies were conducted to optimize the epitaxial deposition parameters for the TiN layer, ensuring compatibility with subsequent graphene growth processes. In-depth investigations into the laser release mechanism revealed that the TiN interlayer undergoes controlled decomposition upon infrared laser irradiation, effectively releasing the graphene-grown CuNi(111) thin film from the sapphire substrate. Extensive experimentation and process optimization establish optimal parameters for stack fabrication and laser release. This method demonstrates successful wafer-scale graphene transfers, utilizing materials and methods fully compatible with established semiconductor manufacturing technologies. In summary, this thesis advances the understanding of transfer challenges associated with graphene grown on metal thin films deposited on sapphire, demonstrating and validating scalable graphene transfer processes compatible with modern semiconductor fabrication. The outcomes substantially enhance the feasibility of integrating graphene into large-scale electronic and photonic device manufacturing. Additionally, recommendations for future process optimizations, such as improving cleaning protocols and exploring direct bonding processes without temporary carriers, are provided. These advancements pave the way for broader adoption of graphene-enabled technologies in industrial-scale applications.
Source: Lirias (KU Leuven)
Author: Tsai, Hung-Chieh
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7113680734
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