Paper GR+EM+ET+MS+NS-FrM7
Achieving Scaled Dielectrics on Graphene Using Atomic Layer Deposition
Friday, November 2, 2012, 10:20 am, Room 13
| Session: |
Graphene Device Physics and Applications |
| Presenter: |
S. Jandhyala, University of Texas at Dallas |
| Authors: |
S. Jandhyala, University of Texas at Dallas
G. Mordi, University of Texas at Dallas
R.M. Wallace, University of Texas at Dallas
J. Kim, University of Texas at Dallas
|
| Correspondent: |
Click to Email |
In order to realize high-performance graphene-based field-effect-devices, local gating of graphene channel is one of the foremost requirements [1]. Therefore, deposition of high-quality, scalable dielectrics on graphene is required. The ability to precisely control thickness and conformally deposit materials makes atomic layer deposition (ALD) an ideal technique for achieving such dielectrics [2]. However, ALD is a surface-reaction limited process [2] and graphene, being sp2 bonded, has no out-of-plane covalent functional groups [3] and this can cause difficulties in initiating the ALD reaction [4]. In previous studies we have shown that using a reversibly physisorbed ozone (O3) functionalization approach, we can deposit high quality ALD oxides (such as Al2O3) on graphene with thicknesses below 5 nm [5]. Further understanding regarding the interaction of O3 and metal precursors with graphene is required for successfully applying the ozone process to deposit different oxides.
In this study, we will use in-situ electrical measurements of graphene devices inside an ALD chamber as a characterization technique in order to understand the adhesion mechanisms of oxidants (such as O3 and H2O) and metal precursors (such as trimethylaluminum-TMA, titanium tetrachloride-TiCl4) on graphene surfaces. The characterization scheme used is packaged back-gated graphene-FETs which can detect the molecules adsorbed on the graphene surface. We will compare exfoliated graphene and chemical vapor deposited (CVD) graphene (which tends to have a higher number of defect sites). Using such real-time electrical measurements, the observed charge scattering mechanisms and the effect on mobility and doping due to the interaction of these molecules with graphene will be presented.
Acknowledgement
This work was funded through the South West Academy of Nanoelectronics (SWAN) program of NRI under SRC.
References
[1] S. K. Banerjee, et al., Pro. of the IEEE 98 (12), pp. 2032-2046 (2010).
[2] R. L. Puurunen, J. Appl. Phys. 97 (12), pp. 121301-121352, (2005)
[3] A. H. Castro Neto, et al., Rev. Mod. Phys. 81 (1), pp. 109-162 (2009)
[4] L. Liao, X. Duan, Mat. Sci. Eng. R 70 (3-6), pp. 354-370, (2010)
[5] S. Jandhyala, et al., ACS Nano, 6 (3), pp. 2722-2730 (2012)