Method for preparing thin ferroelectric or anti-ferroelectric devices

A method for preparing an anti-ferroelectric or ferroelectric device M comprising a thin layer I, being a layer IA or a layer IB, respectively,

• said layer IA comprising a compound chosen from the group (1) consisting of zirconium oxides (ZrO2), lightly doped zirconium oxides, hafnium and zirconium oxides (HfZrOx) wherein the atomic concentration of ZrO2 is greater than or equal to 50%, ZrO2/HfO2 in multilayers wherein the total thickness of the individual ZrO2 layers is greater than the total thickness of the individual HfO2 layers, sodium niobiate (NaNbO3), and silver niobiate (AgNbO3),
• said layer IB comprising a compound chosen from the group (2) consisting of hafnium oxides (HfO2), lightly doped hafnium oxides, aluminum scandium nitrides (AlScN), perovskites with or without lead, hafnium and zirconium oxides (HfZrOx) wherein the atomic concentration of HfO2 is greater than or equal to 50%, and ZrO2/HfO2 in multilayers wherein the total thickness of the individual HfO2 layers is greater than the total thickness of the individual ZrO2 layers,
• said method comprising the following steps:
• (i) a step of depositing on a lower metal electrode M1 a layer I of predominantly amorphous structure comprising a compound selected from group (1) or (2) as defined above to obtain a device M′;
• (ii) a step of depositing on the layer I of the device obtained in the preceding step a layer T with a crystalline or predominantly crystalline structure, the layer T comprising a compound chosen from groups (1) and (2) as defined above, and hafnium and zirconium oxides (HZO) enriched with zirconium, with, by mass, ZrO2>60%;
• (iii) optionally, a step of depositing an upper metal electrode M2′ on said device obtained at the end of step (ii), opposite said lower metal electrode M1;
• (iv) a step of annealing the device obtained at the end of step (ii) or, when it exists, at the end of step (iii) in order to obtain a layer I with a predominantly crystalline structure;
• (v) a selective etching of said layer T and, where present, M2′, in particular complete etching, in order to obtain the layer I with a predominantly crystalline structure on said lower metal electrode M1;
• (vi) optionally, a step of depositing on said layer I obtained at the end of step (v), opposite said lower metal electrode, an upper metal electrode M2;
• the thickness of the layer T being greater than or equal to that of the layer I.