Room temperature PVD TiN to improve the ferroelectric properties of HZO films in the BEoL

Zirconium-doped hafnium oxide (HZO) crystallizes at low temperatures and is thus ideal to implement ferroelectric (FE) functionalities into the back end of line (BEoL). Therefore, metal-ferroelectric-metal (MFM) capacitors are of great interest. Placed in the BEoL, they can be connected either to the drain- or the gate-contact of a standard logic device to realize different emerging FE-embedded non-volatile memory (eNVM) concepts. However, the low crystallization temperature increases also the risk for a premature crystallization of the HZO films during the growth of the top electrode (TE), in particular, if high-temperature processes like atomic layer deposition (ALD) or chemical vapor deposition (CVD) are used. Herein, the TE is deposited at room temperature via physical vapor deposition (PVD). The impact of different process gas flows on the FE properties of the HZO films is studied by X-ray diffraction and polarization versus electric field measurements.