Sputtering and Thermal Effects on the Titania/Si Interface Patrick R. McCurdy, Laura Sturgess, Sandeep Kohli, and Ellen

1. RF Matching Network Capacitance Thermocouple feedthrough Manometer O-ring joint To Flow Controller pump Oxygen silicon substrate holder Flow Controller Argon Heater wire feedthrough Bubbler for Titanium (IV) Isopropoxide Experimental Methods Motivation Experimental Apparatus Heatable waterbath • Ar bubbled through Ti(IV)isopropoxide (5 sccm) introduced downstream from O2 (20 sccm) plasma • XPS/SEM/AES analysis performed on Phi-5800 • XRD analysis done on Brüker D-8 Discover X-ray diffraction system with a Cu X-ray source • Remote-PECVD using 10 W CW plasmas or pulsed plasmas using 250 W 4% duty cycle with 10 ms on-time • Annealing performed in vacuum sealed ampoules • SiO2 is reaching its limit as a gate oxide and a new high-k dielectric must be found to take its place in future IC devices. • TiO2 and other group IVB oxides have many favorable qualities as a future gate oxide. • Many questions still remain about the effects of current Si processing techniques on the metal oxide/Si interface. Sputtering of TiO2 on Si(100) • PECVD TiO2 films behave much like single crystals, i.e. TiO2 is reduced to Ti2O3 and TiO upon sputtering. • Films reach steady state Ti:O ratio of 2:3 in the bulk of film. • Ti:O ratio rises sharply at the Si interface. • Titanium silicide forms at interface upon sputtering. Annealing of TiO2 on Si(100) • No noticeable change is seen in film upon annealing of TiO2 up to 850 ºC except for the growth of an SiO2 layer. • At 900 ºC Ti2O3 is noted in the Ti 2p peak. • At 950 ºC TiO and Ti2O3 found in the Ti 2p region. • The surface is ruptured exposing regions of high SiO2 content. Acknowledgments • Fisher Group Members • National Science Foundation Sputtering and Thermal Effects on the Titania/Si Interface Patrick R. McCurdy, Laura Sturgess, Sandeep Kohli, and Ellen R. Fisher, Colorado State University SEM/SAM of Annealed TiO2 Films a) b) 5 mm 5 mm 5 mm 10 mm SEM—as deposited SEM—850oC anneal c) d) 20 mm 20 mm 20 mm 20 mm SEM—950oC anneal SAM of Si—950oC anneal