Impact of annealing temperature on the remanent polarization and tunneling electro-resistance of ferroelectric Al-doped HfO_x tunnel junction memory

Abstract

The ferroelectric characteristics of a metal-ferroelectric-metal (MFM) ferroelectric tunneling junction (FTJ) capacitor device are investigated herein. The device consists of an aluminum-doped hafnium oxide (HAO) insulator sandwiched between tungsten (W)...

Effect of interfacial SiO2 layer thickness on the memory performances in the HfAlOx-based ferroelectric tunnel junction for a neuromorphic system

“…49,50 The creation of a non-centrosymmetric Pbc2 1 o-phase, which is thermodynamically unstable under typical process conditions, is the source of the ferroelectricity of HAO-based materials. 18 The SiO 2 interlayer controls crystal growth inside the FTJ device to regulate the formation and distribution of the o-phase. Also, it can minimize the concentration of impurities inside the o-phase and increase the volume by controlling the movement of impurities in the device.…”

“…Al-doped HfO 2 (HAO) has a lower switching voltage and a higher polarization value than undoped HfO 2 . 17–23 This is because Al 3+ doping promotes ferroelectric phase formation. 24 In addition, HAO has stable switching endurance and high retention properties, which are technically important compared to undoped HfO 2 .…”

“…25 Moreover, HAO-based ferroelectric devices have advantages such as a high ON/OFF ratio, low energy consumption, fast operating speed, long-term stability, and utilization as memory devices. 15,18,26,27 Therefore, these devices with HAO ferroelectric layers can be efficiently utilized in various applications and provide high performance and stability. 15,19…”

Improved Ferroelectricity and Tunneling Electroresistance by Inducing the ZrO2 Intercalation Layer in La:HfO2 Thin Films

“…When a voltage lower than the coercive voltage ( V c ) of the ferroelectric stack is applied to the electrodes, the current associated with polarization can be nondestructively measured. In order to obtain a reasonable current difference between the ON and OFF states and achieve a high TER, defined as TER = ( I LRS – I HRS )/ I HRS where I LRS and I HRS are the current level as the low-resistance state and high-resistance state, respectively, the FTJ devices must be formed by asymmetric stack layers, in which the TER effect refers to the reversible change in tunneling conductivity through a thin ferroelectric barrier layer induced by the polarization switching of the ferroelectric material. − It has been established that the TER effect correlates with variations in the effective potential barrier, attributed to asymmetric charge screening length at the barrier/electrode interface and the ferroelectric polarization induced built-in polarization field. − It can be seen that researchers commonly introduce interfacial layers, such as TiO 2 , , HfO 2 , , Al 2 O 3 , , and ZrO 2 , between the electrodes and the Zr:HfO 2 ferroelectric layer for studying the FTJ performance. For instance, Max et al proposed a bilayer FTJ structure consisting of hafnium zirconium oxide (HZO) as the ferroelectric layer and aluminum oxide (Al 2 O 3 ) as the tunneling barrier.…”

Modulating the resistive switching stability of HfO2-based RRAM through Gd doping engineering: DFT+U

“…4,5 A variety of binary metal oxides have been found to exhibit resistive switching (RS) behaviors, such as TiO 2 , 6 Al 2 O 3 , 7 Ga 2 O 3 , 8 V 2 O 5 , 9 ZrO 2 10 and HfO 2 . 11 Among them, HfO 2 -based RRAM has been the focus of attention due to its reported promising features such as high endurance (>10 10 ), multi-bit storage potential, scalability potential (<10 nm) and low power consumption. 12–15 RS behaviors of oxide-based RRAM stem from the reversible formation/rupture of conductive filaments (CFs) under an applied electric field, enabling the switching between the low resistance state (LRS) and high resistance state (HRS).…”