Impact of the SiO2 interface layer on the crystallographic texture of ferroelectric hafnium oxide

Abstract

Note: This paper is part of the Special Topic on Materials and Devices Utilizing Ferroelectricity in Halfnium Oxide.

Impact of the interface layer on the cycling behaviour and retention of ferroelectric hafnium oxide

“…Here, the interface growth during crystallisation is clearly visible in case of the 1000 • C RTA. Temperature dependent interface growth has been reported previously for Si and SiGe substrate as well [4,5]. For the latter, an interface thickness of 0.67 nm and 1.99 nm for 650 • C and 1000 • C has been reported, respectively [4].…”

“…As a result, improved ferroelectric properties as well as endurance can be achieved by high temperature annealing and therefore increased interface thickness. However, recent studies have shown that the high temperature anneal modifies the crystallographic texture of the ferroelectric [5] and results in a strongly reduced retention of one state [4]. In addition, fatigue of the ferroelectric is observed, as P R reduces close to 10 4 cycles.…”

“…Furthermore, the polarisation hysteresis behaviour ranged from ferroelectric to strongly asymmetric antiferroelectric (AFE)-like behaviour [4,6]. Additionally, it has been reported that the interface layer is changing in thickness and chemical composition during the dopant activation and crystallisation anneal of the ferroelectric [4,5]. How this affects the cycling behaviour as well as retention of ferroelectric HSO layers in MFIS stacks is investigated in this article.…”

“…In consequence, this is expected to affect the wake-up behaviour of the hafnium oxide layer. This has recently been underlined by structural and electrical characterisation of silicon-doped HfO 2 (HSO) in metal-ferroelectric-insulator-semiconductor (MFIS) stacks [4][5][6]. These layers exhibited pronounced ⟨110⟩ and [111] out-of-plane textures for the ferroelectric orthorhombic phase as well as dendritically shaped grains [5].…”

“…This has recently been underlined by structural and electrical characterisation of silicon-doped HfO 2 (HSO) in metal-ferroelectric-insulator-semiconductor (MFIS) stacks [4][5][6]. These layers exhibited pronounced ⟨110⟩ and [111] out-of-plane textures for the ferroelectric orthorhombic phase as well as dendritically shaped grains [5]. This is in stark contrast to commonly investigated capacitor structures, which have been reported to consist of disc-shaped grains with ⟨100⟩ out-of-plane textures [7][8][9].…”