title: Residual metallic contamination of transferred chemical vapor deposited graphene.
abstract: Integration of graphene with Si microelectronics is very appealing by offering a potentially broad range of new functionalities. New materials to be integrated with the Si platform must conform to stringent purity standards. Here, we investigate graphene layers grown on copper foils by chemical vapor deposition and transferred to silicon wafers by wet etching and electrochemical delamination methods with respect to residual submonolayer metallic contaminations. Regardless of the transfer method and associated cleaning scheme, time-of-flight secondary ion mass spectrometry and total reflection X-ray fluorescence measurements indicate that the graphene sheets are contaminated with residual metals (copper, iron) with a concentration exceeding 10(13) atoms/cm(2). These metal impurities appear to be partially mobile upon thermal treatment, as shown by depth profiling and reduction of the minority charge carrier diffusion length in the silicon substrate. As residual metallic impurities can significantly alter electronic and electrochemical properties of graphene and can severely impede the process of integration with silicon microelectronics, these results reveal that further progress in synthesis, handling, and cleaning of graphene is required to advance electronic and optoelectronic applications.
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Grzegorz
authors: G
authors: Lupina
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Julia
authors: J
authors: Kitzmann
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Ioan
authors: I
authors: Costina
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Mindaugas
authors: M
authors: Lukosius
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Christian
authors: C
authors: Wenger
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Andre
authors: A
authors: Wolff
authors: ‡School of ICT, KTH Royal Institute of Technology, Isafjordsgatan 22, 16440 Kista, Sweden.
authors: Sam
authors: S
authors: Vaziri
authors: ‡School of ICT, KTH Royal Institute of Technology, Isafjordsgatan 22, 16440 Kista, Sweden.
authors: Mikael
authors: M
authors: Östling
authors: §Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw, Poland.
authors: Iwona
authors: I
authors: Pasternak
authors: §Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw, Poland.
authors: Aleksandra
authors: A
authors: Krajewska
authors: §Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw, Poland.
authors: Wlodek
authors: W
authors: Strupinski
authors: ⊥University of Siegen, Hölderlinstr. 3, 57076 Siegen, Germany.
authors: Satender
authors: S
authors: Kataria
authors: ⊥University of Siegen, Hölderlinstr. 3, 57076 Siegen, Germany.
authors: Amit
authors: A
authors: Gahoi
authors: ⊥University of Siegen, Hölderlinstr. 3, 57076 Siegen, Germany.
authors: Max C
authors: MC
authors: Lemme
authors: ∥Infineon Technologies AG, Regensburg 93049, Germany.
authors: Guenther
authors: G
authors: Ruhl
authors: ∥Infineon Technologies AG, Regensburg 93049, Germany.
authors: Guenther
authors: G
authors: Zoth
authors: ¶Infineon Technologies Dresden GmbH, Dresden 01099, Germany.
authors: Oliver
authors: O
authors: Luxenhofer
authors: †IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors: Wolfgang
authors: W
authors: Mehr
keywords: CVD graphene; TXRF; ToF-SIMS; metallic contaminations; transfer