| AVS 63rd International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF-ThA |
| Session: | Self-assembled Monolayers and Organic/Inorganic Interface Engineering |
| Presenter: | Sujitra Pookpanratana, National Institute of Standards and Technology (NIST) |
| Authors: | S. Pookpanratana, National Institute of Standards and Technology (NIST) H. Zhu, George Mason University J.W.F. Robertson, NIST S.N. Natoli, Purdue University E.G. Bittle, NIST C.A. Richter, NIST T. Ren, Purdue University Q. Li, George Mason University C.A. Hacker, NIST |
| Correspondent: | Click to Email |
Attaching and integrating electrochemically-active molecules to a variety of different surfaces is of importance for applications in catalysis, memory devices, and molecular electronics. With the increasing demand for personal electronics, growth in Flash-based memory has increased dramatically. However, the dimensional scaling of memory components faces many critical material limitations. A critical component to the memory device is the floating gate or charge trapping layer. To scale the charge trapping layer to nanometer dimensions, one approach is to use a discrete charge storage layer that is based on organic molecules.1,2,3 Reduction-oxidation (redox) active organic molecules hold potential for memory devices due to their nanoscale dimensions, potential for high charge density, and synthetic flexibility that could be tailor-made for specific electronic functionality.
Here, we investigated the potential of diruthenium-bearing organometallic molecules as the charge trapping layer for memory devices. Diruthenium-bearing organometallic molecules display multiple redox states,4 which makes them ideal to incorporate within non-volatile memory devices. Monolayer assembly is performed in a stepwise fashion by first forming azide-terminated monolayer on SiO2 by using azidoundecyl trimethoxysilane followed by a Cu-catalyzed azide-alkyne cycloaddition click reaction to attach diruthenium (Ru2) compounds (note: SiO2 serves as the tunneling layer).5 Infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the Ru2 attachment. Ultraviolet photoelectron spectroscopy identified the occupied electronic levels of the hybrid organic-inorganic surfaces before and after click reaction. Voltammetric measurements on Ru2-terminated SiO2/Si and Au electrodes confirm that the Ru2 is still electrochemically-active with accessible electronic states integrated on both surfaces.
To complete the memory capacitor device, an Al2O3 layer (serving as a charge blocking layer) was deposited by atomic layer deposition over the molecular layer followed by a metal Pd gate. The impact of different Ru2 compounds on the electronic structure and electrochemical properties of the electrodes and properties of the memory devices will be compared. Our results will provide future design considerations and limitations for molecular-integrated memory devices.
1. T. Shaw et al., IEEE T. Electron. Dev. 58 (3), 826-834 (2011).
2. D. Beckmeier and H. Baumgärtner, J. Appl. Phys. 113 (4), 044520 (2013).
3. H. Zhu, et al., Appl. Phys. Lett. 103 (5), - (2013).
4. W.-Z. Chen and T. Ren, Inorg. Chem. 45 (20), 8156-8164 (2006).
5. S. Pookpanratana, et al., Langmuir 30 (34), 10280-10289 (2014).