| AVS 66th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Films Poster Session |
| Presenter: | Xiaoqing Chu, University of Illinois at Urbana-Champaign |
| Authors: | X. Chu, University of Illinois at Urbana-Champaign Y. Yang, University of Illinois at Urbana-Champaign C. Caroff, University of Illinois at Urbana-Champaign G.S. Girolami, University of Illinois at Urbana-Champaign J.R. Abelson, University of Illinois at Urbana-Champaign |
| Correspondent: | Click to Email |
We report a CVD process to deposit titanium-doped polycrystalline MgB2 films at low temperatures (≤ 400 °C) using Mg (DMADB)2, a highly volatile Mg precursor. The low growth temperature assures that the film does not lose Mg by evaporation, which occurs above 400 °C. When used alone, however, this precursor requires higher temperatures in order to react (it is slightly too stable chemically). We show that CVD proceeds at temperatures as low as 300 °C upon addition of the analogous Ti precursor, Ti(DMADB)2. We identify Ti(DMADB)2 as a catalyst because each Ti molecule drives the decomposition of up to 4 Mg(DMADB)2 molecules. With a high precursor to catalyst pressure ratio, the films are stoichiometric (metal : boron = 1 : 2), and the concentration of oxygen, carbon, and nitrogen is each below the detection limit of ~ 1 at. %. For a film grown at 350 °C, the stoichiometry determined by RBS is Mg0.82Ti0.18B2; it is well crystallized; and the room temperature resistivity is a few hundred µΩ·cm. Literature reports suggest the possibility of superconductivity at T = 10-33 K depending on the doping levels of Ti.