Structural and Electrical Comparison of Si and Zr Doped Hafnium Oxide Thin Films and Integrated FeFETs Utilizing Transmission Kikuchi Diffraction

Abstract

The microstructure of ferroelectric hafnium oxide plays a vital role for its application, e.g., non-volatile memories. In this study, transmission Kikuchi diffraction and scanning transmission electron microscopy STEM techniques are used to compare the crystallographic phase and orientation of Si and Zr doped HfO2 thin films as well as integrated in a 22 nm fully-depleted silicon-on-insulator (FDSOI) ferroelectric field effect transistor (FeFET). Both HfO2 films showed a predominately orthorhombic phase in accordance with electrical measurements and X-ray diffraction XRD data. Furthermore, a stronger texture is found for the microstructure of the Si doped HfO2 (HSO) thin film, which is attributed to stress conditions inside the film stack during crystallization. For the HSO thin film fabricated in a metal-oxide-semiconductor (MOS) like structure, a different microstructure, with no apparent texture as well as a different fraction of orthorhombic phase is observed. The 22 nm FDSOI FeFET showed an orthorhombic phase for the HSO layer, as well as an out-of-plane texture of the [111]-axis, which is preferable for the application as non-volatile memory.

On the Origin of Wake‐Up and Antiferroelectric‐Like Behavior in Ferroelectric Hafnium Oxide

“…A similar observation was also witnessed by other groups. [ 21,27,35 ]…”

Ferroelectric Properties and Polarization Fatigue of La:HfO2 Thin‐Film Capacitors

“…In the o‐phase HfO 2 thin films, the spontaneous polarization is along the c ‐axis of the orthorhombic lattice and both the 180° and 90° domain walls have been reported. [ 6,47–51 ] For example, Shimizu et al have observed 90° ferroelastic domain switching in epitaxial Y:HfO 2 thin films by scanning transmission electron microscopy and synchrotron XRD. [ 48 ] Using the first‐principles theory calculation, Ding et al have reported that there are even ten types of domain walls in the o‐phase HfO 2 .…”

Extraction of Preisach Model Parameters for Fluorite-Structure Ferroelectrics and Antiferroelectrics

“…The proposed modeling framework was used to extract ferroelectric parameters for Al-doped 6,7 , Gd-doped 8 , La-doped 9 , Si-doped 1,[10][11][12] , Sr-doped 13 , Y-doped 14,15 , Zr-doped 4,10,[16][17][18][19][20][21][22][23][24][25][26] , and undoped 4,5 HfO 2 thin films reported in the literature as shown in Fig. 6.…”

“…Ferroelectric field-effect transistors (FeFETs), as emerging memory, find a niche in such applications due to their ultra-fast program/erase time, low operation voltage, and low power consumption [1][2][3] . Despite the fact that hafnium oxide 4,5 and its doped variants (Al-doped 6,7 , Gd-doped 8 , La-doped 9 , Si-doped 1,[10][11][12] , Sr-doped 13 , Y-doped 14,15 , Zr-doped 4,10,[16][17][18][19][20][21][22][23][24][25][26] ) have been extensively studied and characterized over the past few years, little has been done to aggregate those data into ferroelectric properties to provide the insight necessary to create a predictive model for ferroelectrics. Such a predictive model cannot be realized without the accurate determination of a multitude of ferroelectric parameters from various experimental hysteresis loops (Q FE -E FE ).…”