Design, fabrication and characterization of integrated electronic devices based on wafer-scale 2D materials

• Main Author: Zhao, Guangchao
• Other Authors: Tay Beng Kang
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/78422
• Institution: Nanyang Technological University

Transition metal dichalcogenides (TMDs) have received great attention since the discovery of the first two dimensional (2D) material (graphene) in 2004. Molybdenum disulfide (MoS2) has topped the research subjects due to its excellent electrical and optical properties such as high mobility, high thermal stability, and a moderate band gap around 1.8 eV for monolayer. These properties are crucial to achieve a low static power consumption and high On-Off ratio when applied to fabricate electronic devices. What is more important, when ultra-scaled down into nanometer, MoS2 devices can significantly overcome the short channel effect, which makes it possible to substitute silicon (Si) as the basic material in the integrated circuits industry, thus keeping up with the Moore’s law. In this thesis, wafer-scale monolayer MoS2 will first be synthesized by chemical vapor deposition (CVD). Second, the quality of the as-prepared MoS2 samples will be characterized by Raman spectroscopy and photoluminescence (PL). After that, MoS2 will be transferred onto Si substrates where hafnium oxide (HfO2) is previously deposited to form the isolation layer. Then standard micro-fabrication process including electron beam lithography (EBL) and atomic layer deposition (ALD) will be carried out to complete the fabrication of MoS2 field effect transistors (FETs). At last, several tests such as output characteristic and transfer characteristic need to be run to characterize the direct current (DC) performance of the transistors. Other key features to evaluate FETs including carrier mobility and subthreshold swing will also be extracted from the test results.