2D materials proved to be promising candidates in emerging electronic applications. Their properties enable novel applications like biosensing, catalysis or in the field of optical communications and even have the promise to enable further physical transistor scaling. One of the main challenges remains their integration in electronic devices with industry compatible processes. Most of the devices presented in recent literature are limited to the laboratory scale. To make those processes compatible with industrial production, different prerequisites must be satisfied: high quality and large-scale synthesis of the 2D materials, robust reproducibility, low temperature budget, and a relatively fast and cost-effective process. The best approach to synthesise large scale and high quality 2D materials is epitaxial growth on a crystalline substrate, which is often not compatible with direct implementation in devices due to the temperature budget (direct growth methods). As the epitaxial growth is done on templated wafer a transfer process is required to relocate the 2D material on a target wafer. In this study we present a transfer process of epitaxially grown MoS2 on sapphire (Al2O3) wafers to SiO2 substrates. We have further obtained the deterministic stacking of two MoS2 monolayers controlling the twist angle (30 deg). Moreover, the temperature budget of the transfer process is lower than 300°C in all the steps and the process is realised at full 2-inch wafer scale with a process that allows further scaling to larger wafer sizes.

2D MATERIAL DETERMINISTIC STACKING EXPLOITING SCALABLE TRANSFER TECHNIQUES

Rita Asquini
2022

Abstract

2D materials proved to be promising candidates in emerging electronic applications. Their properties enable novel applications like biosensing, catalysis or in the field of optical communications and even have the promise to enable further physical transistor scaling. One of the main challenges remains their integration in electronic devices with industry compatible processes. Most of the devices presented in recent literature are limited to the laboratory scale. To make those processes compatible with industrial production, different prerequisites must be satisfied: high quality and large-scale synthesis of the 2D materials, robust reproducibility, low temperature budget, and a relatively fast and cost-effective process. The best approach to synthesise large scale and high quality 2D materials is epitaxial growth on a crystalline substrate, which is often not compatible with direct implementation in devices due to the temperature budget (direct growth methods). As the epitaxial growth is done on templated wafer a transfer process is required to relocate the 2D material on a target wafer. In this study we present a transfer process of epitaxially grown MoS2 on sapphire (Al2O3) wafers to SiO2 substrates. We have further obtained the deterministic stacking of two MoS2 monolayers controlling the twist angle (30 deg). Moreover, the temperature budget of the transfer process is lower than 300°C in all the steps and the process is realised at full 2-inch wafer scale with a process that allows further scaling to larger wafer sizes.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1658247
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