On the Electrical Characteristics of Ferroelectric FinFET Using Hafnium Zirconium Oxide with Optimized Gate Stack

Abstract

We investigated a short-channel ferroelectric FinFET using a ferroelectric HfZrO thin film as gate dielectrics, and scaled down the channel length to 60 nm to study the short-channel effect and the ferroelectricity. The HfZrO FinFETs exhibited improved short-channel performance including subthreshold swing improvement and reduced drain-induced barrier lowering effect. By using pulsed I-V measurement method, we confirmed that the thickness tradeoff between HfZrO ferroelectric layer and buffered layer are critical to alleviate the influence of interface traps and simultaneously obtain the ferroelectricity in HfZrO FinFET devices with the consideration of sidewall traps. Interface traps may cause unwanted off-state leakage current and mismatching negative capacitance.Here, we demonstrated that the ferroelectric behavior can be achieved by simultaneously increasing HfZrO thickness to obtain the optimized polarization and adopt appropriate buffered layer to screen the traps effect under ferroelectric domain switching.

Ferroelectric field-effect transistors based on HfO2: a review

“…On the other hand, the possibility of conformal 3D deposition of FE HfO 2 films is very attractive and has in the past allowed the fabrication of 3D vertical deep trench capacitors with Al doped HfO 2 thin films [140], reaching the aspect ratio of 13:1 and opening the avenue for high density 1T-1C FeRAM applications. Moreover, these assets are responsible for the recent demonstration of 3D vertical FeFETs [21], but also nanowire FeFETs [86,104], as well as FinFETs [138,141,142] and GAA devices [89,143] with embedded FE HfO 2 /HZO (figures 10(c), (d)). The vast adoption of HfO 2 films for conventional HKMG transistors and the dedicated integration know-how have recently facilitated the co-integration of FeFETs with logic transistors (figure 10(e)), sharing the same active area and having the gate-to-gate distance of only 100 nm [22].…”

Impact of Series-Connected Ferroelectric Capacitor in HfO₂-Based Ferroelectric Field-Effect Transistors for Memory Application

“…The negative capacitance effect can break the physical limitation of Boltzmann tyranny leading to a sub-60mV/decade subthreshold swing (SS) under an ultralow supply voltage, which is critical for the application in Internet of Things (IoT) [7]- [9]. Hafnium-oxide (HfO2)-based thin film with stable ferroelectric properties at the nanoscale has good scalability and compatibility with the standard complementary metal-oxide-semiconductor (CMOS) integration technology [4], [5], [10]. Adding a ferroelectric layer into the gate stack of the metal-oxide-semiconductor field-effect transistors (MOSFETs) causes a unique operation behavior of the FeFETs, that is, there is a hysteresis loop in the transfer curve due to the polarization in ferroelectric material [11].…”