Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 26: Poster Session - Graphene: Growth, Structure and Substrate Interaction

O 26.1: Poster

Monday, March 16, 2020, 18:15–20:00, P1A

Investigating the quality of CVD-grown graphene on germanium using in-situ surface science methods — •Andreas Becker, Jarek Dabrowski, Mindaugas Lukosius, and Christian Wenger — IHP, Frankfurt (Oder), Germany

Germanium epitaxially grown on silicon has emerged as a relevant substrate for graphene growth because it is possibly compatible with established CMOS processing. Besides optimizing wafer-scale graphene growth on germanium template and subsequent transfer, we are exploring ways to directly integrate graphene growth into technological processing. However, major challenges are the relatively low quality of graphene on the standard orientation Ge(001) and the high required synthesis temperature. These challenges motivated an investigation of the growth process using a high-pressure preparation chamber for chemical vapor deposition that is connected to a surface science cluster tool. As a prerequisite for reliable graphene growth, we present a detailed study of the germanium substrate pre-cleaning and describe how to avoid etch pit formation. Furthermore, we investigated the influence of growth temperature on quality of graphene on Ge(001), Ge(110) and Ge(111) using scanning tunneling microscopy, low-energy electron diffraction and Raman spectroscopy. We discuss graphene grain size and morphology, epitaxial alignment and intragranular defect density and conclude that the best graphene quality is obtained on Ge(110) at a growth temperature near the substrate melting point. Finally, we intend to bring up a discussion how enhancement of substrate-mediated catalytic etching might help improve the graphene quality.