Ferroelectric deep trench capacitors based on Al:HfO₂ for 3D nonvolatile memory applications

A thermally robust and thickness independent ferroelectric phase in laminated hafnium zirconium oxide

“…Titanium nitride was used as top and bottom electrode to form metal ferroelectric metal (MFM) capacitors. The bottom electrodes were deposited by thermal ALD using TiCl 4 and NH 3 at 450 • C using an ASM A412 batch furnace. The top electrode for planar 2D samples was deposited by sputtering TiN thin films to minimize the thermal stress for the ferroelectric.…”

“…Samples for electrical characterization were prepared by e-beam evaporating metal dots (5nm Ti glue layer/20nm Pt electrode) on top of the TiN top electrode via a shadow mask. The TiN top electrode was etched using these metal dots as masking layer by an SC1 (NH 4 were prepared using a process flow described in detail elsewhere. 4 This process flow uses TiN top electrodes deposited by pulsed CVD at 400 • C. The 3D samples were also annealed at 650 • C for 20s to guarantee the formation of a crystalline phase.…”

“…The TiN top electrode was etched using these metal dots as masking layer by an SC1 (NH 4 were prepared using a process flow described in detail elsewhere. 4 This process flow uses TiN top electrodes deposited by pulsed CVD at 400 • C. The 3D samples were also annealed at 650 • C for 20s to guarantee the formation of a crystalline phase. The composition of the HZO films was determined by x-ray photoelectron spectroscopy on a ReVera Veraflex tool using Al-Kα excitation and analyzer pass energy of 141.2 eV.…”

“…2 Primarily motivated by memory applications, thickness scaling to the single digit nanometer range, 3 3D-capacitor integration, 4 as well as ferroelectric field effect transistor implementation at the 28 nm node 5 has already been demonstrated. First results on non-memory applications of FE-HfO 2 such as negative capacitance FETs 6 or high energy storage capacitors using antiferroelectric hafnium oxide (AFE-HfO 2 ) 7 have already been reported.…”

Fabrication and investigation of three-dimensional ferroelectric capacitors for the application of FeRAM

“…9,10 In recent years ferroelectric capacitors with Al-doped HfO 2 films have also been studied. 11,12 Some quantitative studies of 3D ferroelectric capacitors on trench holes with PZT films were shown in Reference 4 and 5. The sidewalls of narrower trench holes seemed to have lower effective contribution to remnant polarization.…”