与CMOS后端工艺高度兼容的Hf0.5Zr0.5O2铁电电容的制备和性能研究

Preparation and Properties of Hf0.5Zr0.5O2 Ferroelectric Capacitor Compatible with Back-End Integration

最近,在氧化铪薄膜材料中掺杂适量元素发现了铁电性,因为氧化铪薄膜材料与传统的钙钛矿结构铁电材料相比具有可微缩性化、较大的矫顽电场、与CMOS后端工艺高度兼容等优势,从而引起了广泛的关注.该文对应用于铁电场效应晶体管(FeFET)的存储介质Hf0.5Zr0.5O2(HZO)基铁电薄膜的制备进行了研究.采用原子层沉积法(ALD)制备HZO基铁电薄膜,研究了不同厚度(9nm、19nm、29nm)、不同顶电极(TaN、Pt),以及不同退火温度(450~750℃)对HZO铁电薄膜的铁电性能的影响.结果表明,选用TaN作为上电极,退火温度为550℃时,19nm厚氧化铪铁电薄膜表现出更加优异的铁电性能.同时,表征了HZO铁电薄膜的保持和疲劳性能,以及HZO铁电薄膜在高低温环境下的稳定性.

Recently,ferroelectricity was found in hafnium oxide thin film doped with appropriate elements. Hafnium oxide thin films are gaining increasing interest, because they have various advantages such as scalability, high coercive electric field, and the complementary metal-oxide-semiconductor (CMOS)-compatibility compared with traditional ferroelectric materials with a perovskite structure. In this paper, we fabricated the Hf 0.5 Zr 0.5 O 2 -based ferroelectric thin film for ferroelectric field effect transistor (FeFET) by atomic layer deposition (ALD) and investigated the effects of thicknesses (9 nm, 19 nm, 29 nm), top electrodes (TaN, Pt) and annealing temperatures (450~750 ℃) on the ferroelectric properties of HZO ferroelectric thin films. The 19-nm-thick hafnium oxide ferroelectric thin film annealed at 550 ℃ exhibits superior ferroelectric properties. Meanwhile, the retention and fatigue properties of HZO ferroelectric thin films and the stability of HZO ferroelectric thin films in high and low temperature environments were characterized.