Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10-6 in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm-1. The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.
Bibliographical noteFunding Information:
AVR and LMB gratefully acknowledge the financial support from the Swedish Research Council and Carl Tryggers Foundation. AVK and AIA acknowledge the support of the A*MIDEX project (n? ANR-11-IDEX-0001-02) funded by the ?Investissements d?Avenir? French Government program, managed by the French National Research Agency (ANR) and by LASERNANOCANCER project of the INCA INSERM (INCa-DGOS-Inserm 6038). BNC and EDD acknowledge support from ONR Grant N00014-11-1-0850 and the MRSEC Program of the NSF under Grant No. DMR- 0819885. BNC and EDD also acknowledge additional support for work done using the University of Minnesota Nanofabrication Center and Characterization Facility provided by the NSF NNIN network. BNC acknowledges support of a University of Minnesota Thesis Research Travel Grant. The authors are also grateful to Piet Trompenaars (FEI Electron Optics, The Netherlands) for his dedicated help in the design of thin needles used for EBID process, and to Valter Str?m (MSE Department, KTH, Sweden) for the design of the circuit for the electrical measurements. This work was conducted within the framework of the COST Action CM1301 (CELINA).
- 3D nanopatterning
- gas-assisted EBID
- high-purity insulator
- titanium tetraisopropoxide (TTIP)