Achieving wafer scale synthesis of molybdenum ditelluride through precursor engineering

Eladl, Marwan

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https://hdl.handle.net/2142/120181 Copy

Description

Title

Achieving wafer scale synthesis of molybdenum ditelluride through precursor engineering

Author(s)

Eladl, Marwan

Issue Date

2023-05-05

Director of Research (if dissertation) or Advisor (if thesis)

Zhu, Wenjuan

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

2D, TMD, CVD, MOCVD, Growth, Precursor, MoTe2, Wafer Scale

Abstract

Transition metal telluride (TMT) materials have very interesting electronic, magnetic, and phase change properties, that make them suitable for novel device structures such as reconfigurable, spin orbit torque, and phase change devices. However, adoption of these devices in industry is hindered by poor quality, small crystal size, and nonuniform growth of TMT material. As such, it is necessary to develop high quality, wafer scale processes for TMT growth. In this thesis, I explore two new precursors, molybdenum pentachlo- ride (MoCl5) and dibutyl tellurium ((C4H9)2Te) for the growth of molybde- num ditelluride (MoTe2). I separately test each precursor with conventional precursors. Specifically, running experiments using MoCl5 with tellurium powder in a chemical vapor deposition (CVD) growth and (C4H9)2Te with molybdenum oxide (MoO3) in a metal organic chemical vapor deposi- tion (MOCVD) growth. I was able to achieve single crystal growth of MoTe2 at temperatures as low as 500°C. This showed that MoCl5’s higher vapor pressure allowed for low temperature growth. Additionally, by increasing the temperature of the growth I showed that 2H-MoTe2 growth was preferable at high temperatures and 1T’-MoTe2 at lower temperatures. In the exploration of (C4H9)2Te, I was able to better understand the breakdown mechanisms of the precursor and the role hydrogen plays in this process. Using this infor- mation, I identify which molybdenum precursors were incompatible with the (C4H9)2Te. Finally, I explore the combination of MoCl5 and (C4H9)2Te in a MOCVD growth experiment. Using this combination I was able to achieve high quality wafer scale growth of 1T’-MoTe2. The results of my work show the viability of these precursors as alternatives to conventional precursors. This work also takes a step forward towards the commercialization of TMT device by reducing growth temperatures towards back-end compatibility.

Graduation Semester

2023-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Marwan Eladl

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