Electrical properties of ferroelectric Y-doped Hf–Zr–O thin films prepared by chemical solution deposition

Abstract

Y-doped Hf-Zr-O (Y-HZO) films have been prepared by chemical solution deposition (CSD). It is shown that good ferroelectric property can be obtained for the Y- HZO film with an Y concentration of 3.2% after 800 oC crystallization annealing at a reduced pressure of 50 Pa. It is also demonstrated that the reduced pressure pre-annealing at temperatures as low as 400 oC is effective to obtain good ferroelectric properties, regardless of the crystallization annealing ambient. This is presumably because the pre-annealing under reduced pressure promotes the formation of nuclei of orthorhombic phase.

Impact of CeOx layer insertion on ferroelectric properties of Hf-Zr-O films prepared by chemical solution deposition

“…Without the insertion of CeO x layer, although the ferroelectric P-E hysteresis loops were obtained for a single Y-HZO layer, a remanent polarization, P r , is limited to about 10 μC cm −2 , which is similar to the results of our previous study. 29) On the other hand, it is clearly demonstrated in Fig. 2 that by inserting a CeO x layer at the top or bottom, ferroelectric properties were significantly enhanced.…”

“…The preparation of thin films by CSD is similar to that reported in our previous works. 29,30) In this work, CeO x /Y-HZO or Y-HZO/CeO x layered structures were fabricated by CSD on Pt/Ti/SiO 2 /Si substrate. Source solution was prepared using hafnium (IV) acetylacetonate (Hf(acac) 4 ), zirconium (IV) acetylacetonate (Zr(acac) 4 ) and yttrium (III) acetylacetonate (Y(acac) 3 ) were used for Y-HZO layers, and cerium (III) acetylacetonate (Ce(acac) 3 ) was used for CeO x deposition as precursors.…”

“…Y composition is fixed at 3.2% which showed good ferroelectric properties in our previous report. 29) CeO x /undoped HZO layered structure was fabricated and characterized, too, to clarify the effect of CeO x layer insertion. To confirm the layered structure and interdiffusion of each element, a CeO x /Y-HZO/CeO x sandwiched structure was fabricated.…”

“…[26][27][28] We have previously investigated ferroelectric Y-and La-doped HZO thin films prepared by CSD and reported that good ferroelectric properties can be obtained by reduced pressure annealing without O 2 supply, which promotes the growth of o-phase probably because of the oxygen vacancy introduction. 29,30) The reduced pressure crystallization anneal is also applicable to sputtered HZO films to obtain good ferroelectric properties and stability. 31) In addition, even the irradiation of catalytically generated atomic hydrogen into as-deposited sputtered HZO films improves the ferroelectric properties, which is believed to be due to the introduction of oxygen vacancies.…”

Overcoming Size Effects in Ferroelectric Thin Films

“…To improve the retention and endurance of the capacitor, there is a method of inserting the interlayer between HZO and the electrode or changing the doping element of HZO. [132][133][134][135][136][137][138][139][140][141][142]…”