PMID- 34407525
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20210908
IS  - 1361-6528 (Electronic)
IS  - 0957-4484 (Linking)
VI  - 32
IP  - 48
DP  - 2021 Sep 8
TI  - Effect of ferroelectric and interface films on the tunneling electroresistance of 
      the Al(2)O(3)/Hf(0.5)Zr(0.5)O(2)based ferroelectric tunnel junctions.
LID - 10.1088/1361-6528/ac1ebe [doi]
AB  - Ferroelectric random-access memory (FRAM) based on conventional ferroelectric 
      materials is a non-volatile memory with fast read/write operations, high 
      endurance, and 10 years of data retention time. However, it suffers from 
      destructive read-out operation and lack of CMOS compatibility. HfO(2)-based 
      ferroelectric tunnel junctions (FTJ) may compensate for the shortcomings of FRAM 
      by its CMOS compatibility, fast operation speed, and non-destructive readout 
      operation. In this study, we investigate the effect of ferroelectric and 
      interface film thickness on the tunneling electroresistance or ON/OFF current 
      ratio of the Hf(0.5)Zr(0.5)O(2)/Al(2)O(3)based FTJ device. Integrating a thick 
      ferroelectric layer (i.e. 12 nm Hf(0.5)Zr(0.5)O(2)) with a thin interface layer 
      (i.e. 1 nm Al(2)O(3)) resulted in an ON/OFF current ratio of 78. Furthermore, to 
      elucidate the relationship between ON/OFF current ratio and interfacial 
      properties, the Hf(0.5)Zr(0.5)O(2)-Al(2)O(3)films and Ge-Al(2)O(3)interfaces are 
      examined via time-of-flight secondary ion mass spectrometry depth profiling mode. 
      A bilayer oxide heterostructure (Hf(0.5)Zr(0.5)O(2)/Al(2)O(3)) is deposited by 
      atomic layer deposition (ALD) on the Ge substrate. The ON/OFF current ratio is 
      enhanced by an order of magnitude when the Hf(0.5)Zr(0.5)O(2)film deposition mode 
      is changed from exposure (H(2)O) ALD to sequential plasma (sequential O(2)-H(2)) 
      ALD. Moreover, the interfacial engineering approach based on thein situALD 
      H(2)-plasma surface pre-treatment of Ge increases the ON/OFF current ratio from 9 
      to 38 by reducing the interfacial trap density state at the Ge-Al(2)O(3)interface 
      and producing Al(2)O(3)with fewer oxygen vacancies as compared to the wet etch 
      (HF + H(2)O rinse) treatment of the Ge substrate. This study provides evidence of 
      strong coupling between Hf(0.5)Zr(0.5)O(2)and Al(2)O(3)films in controlling the 
      ON/OFF current ratio of the FTJ.
CI  - (c) 2021 IOP Publishing Ltd.
FAU - Shekhawat, Aniruddh
AU  - Shekhawat A
AD  - Department of Mechanical and Aerospace Engineering, University of Florida, 
      Gainesville, FL, 32611, United States of America.
FAU - Hsain, H Alex
AU  - Hsain HA
AD  - Department of Materials Science and Engineering, North Carolina State University, 
      Raleigh, NC, 27695, United States of America.
FAU - Lee, Younghwan
AU  - Lee Y
AD  - Department of Materials Science and Engineering, North Carolina State University, 
      Raleigh, NC, 27695, United States of America.
FAU - Jones, Jacob L
AU  - Jones JL
AD  - Department of Materials Science and Engineering, North Carolina State University, 
      Raleigh, NC, 27695, United States of America.
FAU - Moghaddam, Saeed
AU  - Moghaddam S
AUID- ORCID: 0000-0002-9171-6500
AD  - Department of Mechanical and Aerospace Engineering, University of Florida, 
      Gainesville, FL, 32611, United States of America.
LA  - eng
PT  - Journal Article
DEP - 20210908
PL  - England
TA  - Nanotechnology
JT  - Nanotechnology
JID - 101241272
SB  - IM
OTO - NOTNLM
OT  - atomic layer deposition
OT  - ferroelectrics
OT  - hafnium oxide
OT  - interface engineering
OT  - tunnel junctions
EDAT- 2021/08/19 06:00
MHDA- 2021/08/19 06:01
CRDT- 2021/08/18 20:09
PHST- 2021/06/25 00:00 [received]
PHST- 2021/08/18 00:00 [accepted]
PHST- 2021/08/19 06:00 [pubmed]
PHST- 2021/08/19 06:01 [medline]
PHST- 2021/08/18 20:09 [entrez]
AID - 10.1088/1361-6528/ac1ebe [doi]
PST - epublish
SO  - Nanotechnology. 2021 Sep 8;32(48). doi: 10.1088/1361-6528/ac1ebe.