Characterization of Hafnium Nitride Films Deposited by Plasma ALD
Thursday, October 18, 2007, 5:30 pm, Room 4C
Conductive hafnium nitride films have been deposited by plasma ald in the Oxford Instruments OpAL reactor. TEMAH was used as the hafnium source and nitrogen was provided from a remotely mounted inductively coupled plasma source. The influence of nitrogen-hydrogen and ammonia plasmas on film properties such as stoichiometry, refractive index, and resistivity is reported. Film thickness and refractive index were determined by ellipsometry. The resistivity was measured using a 4 point probe. The composition of the film was estimated from Auger electron spectroscopy and XRD was used to confirm the amorphous nature of the film. Depending on the plasma composition, the growth per cycle was in the range 0.7 - 1.5 Å/cycle and the refractive index varied from 1.4 - 2.3. The minimum measurable resistivity of the films was 5 μ Ω cm. Hydrogen plasma has signifcant effect on the conductivity of the deposited iflms compared to nitrogen plasma. The thickness of the films remained unchanged when left exposed to ambient air.