Ferroelectricity has been reported in the atomic layer deposition (ALD) of HfO2 with Al, Y, or Si dopants. Previous work (by Joe McGlone) at RIT demonstrated functional FeFETs using silicon doped HfO2 (Si:HfO2) as the gate dielectric. The recent addition of a Savannah ALD system at RIT has made deposition of doped HfO2 films possible. Recipes have been developed (by Casey Gonta) for deposition of aluminum doped HfO2 and, this year, ferroelectricity has been shown in Al:HfO2 (by Josh Eschle) at RIT. My work follows in the footsteps of the aforementioned research to make a working FTJ. Metal Ferroelectric Metal (MFM) devices were fabricated using Titanium Nitride (TiN) as the top electrode and Tantalum (Ta) or Nickel Silicide (NiSi) as the bottom electrode. The thickness of the Al:HfO2 layer ranges from 3 nm to 5 nm with only 1 to 2 aluminum doping cycles. Unfortunately, the deposited hafnium film did not display ferroelectric behavior and so by default, capacitors were fabricated and tested.
"Fabrication and Characterization of Ferroelectric Tunnel Junctions with Different Bottom Electrodes,"
Journal of the Microelectronic Engineering Conference: Vol. 24
, Article 45.
Available at: https://scholarworks.rit.edu/ritamec/vol24/iss1/45