| AVS 58th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Tuesday Sessions |
| Session GR-TuA |
| Session: | Graphene on Dielectrics, Graphene Transfer to Novel Substrates |
| Presenter: | Srikar Jandhyala, University of Texas at Dallas |
| Authors: | S. Jandhyala, University of Texas at Dallas G. Mordi, University of Texas at Dallas B. Lee, University of Texas at Dallas J. Kim, University of Texas at Dallas P.-R. Cha, Kookmin University, Korea |
| Correspondent: | Click to Email |
Graphene, being a two dimensional material, is one of the most promising alternative channel materials for post-Si generation [1-3]. However, being just one atom thick and having an inert surface, it poses a huge challenge to develop a top-gate dielectric process for graphene-based devices. Several techniques are currently being explored for depositing dielectrics including physical-vapor deposition (PVD), chemical-vapor deposition (CVD) and atomic layer deposition (ALD) after chemical ‘functionalization’ of graphene (using NO2 or O3) or after depositing nucleation layers (such as Al, PTCA, PVA) on graphene [3].
Here, we will present a novel technique developed by our group for depositing ALD high-k dielectrics such as Al2O3 on graphene through ozone functionalization [4]. Physisorption of ozone has been claimed to be the plausible mechanism for functionalizing the graphene surface [5]. Based on Langmuir adsorption equation, the amount of ozone adsorbed on graphene can be increased by increasing the partial pressure of ozone. By utilizing this, we have been able to precisely control the dielectric thicknesses and successfully scale dielectrics on graphene down to a thickness of ~3 nm. We employed both AFM on HOPG/graphene and in-situ electrical characterization of graphene-FETs in order to understand the adhesion mechanisms of ozone with graphene, enabling the deposition of ALD dielectrics. For in-situ electrical characterization, we used package-level devices with back-gated graphene devices to detect molecules adsorbed on graphene surface. The observed charge scattering mechanisms and effect on mobility due to the interaction of ozone with graphene as a function of temperature and amount of ozone will be presented. In-situ studies regarding the role of TMA (Tri-methyl Aluminum) will also be discussed based on experiments in actual ALD chambers.
Acknowledgement
NRI-SWAN (Theme # 1464.012) and Korea-US International R/D program by MKE
References
[1] P. Avouris, Nano Lett. 10 (11), pp. 4285-4294 (2010)
[2] V. V. Cheianov, et al., Science 315 (5816), pp. 1252-1255 (2007)
[3] S. K. Banerjee, et al., Pro. of IEEE, 98 (10), pp. 2032-2046 (2010))
[4] B. Lee, et al., Appl. Phys. Lett., 97 (4), 043107 (2010)
[5] G. Lee, et al., Jour. Phys. Chem. C, 113 (32), pp. 14225-14229 (2009)