Search query: FeFET ZrO2 seed layer

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abstract: Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub>(HZO) based ferroelectric field effect transistor (FeFET) with a ZrO<sub>2</sub> seed layer was demonstrated. It was found that the ZrO<sub>2</sub> seed layer could effectively improve the ferroelectric properties of the (hafnium zirconium oxide) HZO thin film. The remanent polarization and the coercive voltage of the metal ferroelectric insulator semiconductor (MFIS) structure with the ZrO<sub>2</sub> seed layer were larger than those without the seed layer. Moreover, the FeFET with the ZrO<sub>2</sub> seed layer showed wider counterclockwise hysteresis loops in the transfer characteristics than that without the seed layer, achieving a large memory window of about 2.8 V. These results validate the advantages of the ZrO<sub>2</sub> seed layer in promotion of FeFET performance and thus warrant further study.
author_names: Wenwu Xiao

Chen Liu

Yue Peng

Shuaizhi Zheng

Qian Feng

Chunfu Zhang

Jincheng Zhang

Yue Hao

Min Liao

Yichun Zhou
title: Performance Improvement of Hf0.5Zr0.5O2 Based Ferroelectric Field Effect Transistors With ZrO2 Seed Layers
venue: IEEE Electron Device Letters
year: 2019

abstract: The HfO2 based ferroelectric field effect transistor (FeFET) with a metal/ferroelectric/insulator/semiconductor (MFIS) gate stack is currently being considered as a possible candidate for high density and fast write speed non volatile memory. Although the retention performance of the HfO2 based FeFET with a MFIS gate stack could satisfy the requirements for practical applications, its memory window (MW) and reliability with respect to endurance should be further improved. This work investigates the advantage of employing ZrO2 seed layers on the MW, retention, and endurance of the Hf0.5Zr0.5O2 (HZO) based FeFETs with MFIS gate stacks, by using fast voltage pulse measurements. It is found that the HZO based FeFET with a ZrO2 seed layer shows a larger initial and 10 year extrapolated MW, as well as improved endurance performance compared with the HZO based FeFET without the ZrO2 seed layer. The results indicate that employing of a direct crystalline high k/Si gate stack would further improve the MW and reliability of the HfO2 based FeFETs.
author_names: Wenwu Xiao

Chen Liu

Yue Peng

Shuaizhi Zheng

Qian Feng

Chunfu Zhang

Jincheng Zhang

Yue Hao

Min Liao

Yichun Zhou
title: Memory Window and Endurance Improvement of Hf0.5Zr0.5O2 Based FeFETs with ZrO2 Seed Layers Characterized by Fast Voltage Pulse Measurements
venue: Nanoscale Research Letters
year: 2019

abstract: The effect of crystallized ZrO2 (ZrO2 seed) amorphous Hf0.43Zr0.57O2 (HZO; HZO seed) and amorphous Al2O3 (Al2O3 seed) seed layers on the ferroelectricity of HZO films was investigated. The remanent polarization of a TiN electroded capacitor with a ZrO2 seed layer was much larger than that of capacitors with a HZO seed, Al2O3 seed, or no seed layer. Furthermore, the maximum 2P r was exhibited when the thickness of the ZrO2 seed layer was 2 nm. Large grain growth was observed, which satisfied the same lattice pattern between ZrO2 and HZO films, and indicates that the ZrO2 seed layer plays an important role in the nucleation of the HZO film.
author_names: Takashi Onaya

Toshihide Nabatame

Naomi Sawamoto

Akihiko Ohi

Naoki Ikeda

Toyohiro Chikyow

Atsushi Ogura
title: Improvement in ferroelectricity of Hf x Zr1 x O2 thin films using ZrO2 seed layer
year: 2017

author_names: Onaya Takashi

Nabatame Toshihide

Sawamoto Naomi

Ohi Akihiko

Ikeda Naoki

Chikyow Toyohiro

Ogura Atsushi
title: Effect of ZrO2 seed layer on ferroelectricity of HfxZr1 xO2 thin film
year: 2017

abstract: Abstract Effects of Cr N ZrO 2 seed layer deposited on glass substrates before the deposition of C/Co Cr Pt/Cr Ti layers for longitudinal recording media have been investigated. The product of v and I s the activation volume and the saturation magnetization per unit volume, media noise N d and S 0 N d which is the half value of peak to peak output voltage of an isolated pulse over N d at 11.8 kFC/mm, are evaluated. We find that vI s is decreased by adding N and ZrO 2 to Cr seed layer. N d is reduced as vI s decreases by adding nitrogen to the Cr seed layer. This is mainly due to the decreased grain sizes of both Cr Ti underlayer and Co Cr Pt magnetic layer. The N d is further reduced by the addition of ZrO 2 to the Cr N seed layer. Highest S 0 N d is achieved for the media with Cr N ZrO 2 seed layer. On the other hand, the media with Cr ZrO 2 seed layer deposited without nitrogen show the higher N d Therefore the decrease of the grain size by addition of nitrogen into Ar is essential to reduce N d and the ZrO 2 addition to the Cr N seed layer seems to enhance the effect of grain size reduction by nitrogen addition.
author_names: Hiroyuki Suzuki

David D Djayaprawira

Yoshio Takahashi

Akira Ishikawa

Ono Toshinori

Yotsuo Yahisa
title: Effects of Cr N ZrO2 seed layer formed on glass substrates for longitudinal recording media
year: 1999

abstract: We have experimentally demonstrated fully suspended nanowire (NW) gate all around (GAA) negative capacitance (NC) field effect transistors (FETs) with ultrasmall channel dimensions (5 nm \times 12.5 $nm) they exhibit a remarkable \mathrm{I}_{on} \mathrm{I}_{off} ratio of over 1010. This work, for the first time, experimentally studies and compares the structures of metal ferroelectric metal insulator semiconductor (MFMIS) and metal ferroelectric insulator semiconductor (MFIS) NCFETs. The GAA with the MFMIS structure has a higher on state current owing to the metallic equal potential layer and superior S.S ._{min} of 39.22 mV/decade. A ZrO2 seed layer is inserted under HfZr $_{1 x} \mathrm{O}_{x} HZO) to improve the ferroelectric crystallinity. Consequently, post metal annealing (PMA) the conventional crystallization annealing step, can be omitted in the presence of o phase. The gate current \mathrm{I}_{G} is monitored to verify the multi domain HZO. A negative DIBL of 160 mV/V is observed because of the strong NC effect corresponding to previous simulated results.
author_names: Shen-Yang Lee

Han-Wei Chen

Chiuan-Huei Shen

Po-Yi Kuo

Chun-Chih Chung

Yu-En Huang

Hsin-Yu Chen

Tien-Sheng Chao
title: Experimental Demonstration of Performance Enhancement of MFMIS and MFIS for 5 nm x 12.5 nm Poly Si Nanowire Gate All Around Negative Capacitance FETs Featuring Seed Layer and PMA Free Process
venue: 2019 Silicon Nanoelectronics Workshop (SNW)
year: 2019

abstract: In this article, we successfully fabricated nanowire (NW) negative capacitance (NC) related ferroelectric FETs (FE FETs) with two structures: trigate (TG) and gate all around (GAA) Planar capacitors with a metal FE metal (MFM) structure were investigated first. Post metal annealing (PMA) at 700 degC resulted in the best ferroelectricity. This condition was considerably different from that of directly stacking onto NWs because of the difference in size and curvature between planar and TG or GAA structures. Because of the addition of an underlying ZrO<sub>2</sub> seed layer, Hf<inline formula> <tex math notation="LaTeX"$_{{1} {x} /tex math>/inline formula>Zr<sub><italic>x</italic>/sub>O<sub>2</sub> in the gate stack has been crystallized before the PMA process. In addition, two different gate stack configurations, MFM insulator semiconductor (MFMIS) and metal FE insulator semiconductor (MFIS) were investigated for the GAA structure. We determined that MFMIS displayed considerably more favorable subthreshold behavior and ON state current compared with MFIS. NC related phenomena, such as negative drain induced barrier lowering and negative differential resistance, were observed.
author_names: Shen-Yang Lee

Han-Wei Chen

Chiuan-Huei Shen

Po-Yi Kuo

Chun-Chih Chung

Yu-En Huang

Hsin-Yu Chen

Tien-Sheng Chao
title: Effect of Seed Layer on Gate All Around Poly Si Nanowire Negative Capacitance FETs With MFMIS and MFIS Structures: Planar Capacitors to 3 D FETs
venue: IEEE Transactions on Electron Devices
year: 2020

abstract: A stable substrate is extraordinarily important for the trace detection of Surface Enhanced Raman Scattering technique. We have designed in this paper a simple seed growth method to prepare Ag@ZrO2 core shell nanoparticles as well as regulate the core shell ratio by adjusted concentration of zirconium propoxides added. The shell thickness effect and spacing on SERS activities have been simulated in different finite time domains, which goes perfectly with those previous experiment results. With Ag@ZrO2 core shell nanoparticles adopted as the SERS substrate and R6G as molecular probe, the detection range could reach as great as 10 8 M. The regression model, obtained through principal component analysis, is adopted for some rapid and precise detection; and the determination coefficient (R2) is going up to 0.9743, proving that the SERS substrate we have prepared has extremely high detection accuracy. To explore the stability of core shell nanoparticles, we have taken both two different cases of strong acid solution as well as strong alkali solution for the core shell nanoparticle etching, and this is how a SERS test could be carried out. These experimental results have indicated that the outer zirconia layer could keep the silver surface from oxidation and its stability is ensured, quite crucial for the applied SERS.
author_names: Yong-Feng Zhou

Pei Liang

De Zhang

Lisha Tang

Qianmin Dong

Shangzhong Jin

Dejiang Ni

Zhi Yu

Jia-ming Ye
title: A facile seed growth method to prepare stable Ag@ZrO2 core shell SERS substrate with high stability in extreme environments.
venue: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
year: 2019

abstract: For the first time, two layer stacked nanowire gate all around (GAA) negative capacitance (NC) field effect transistors (FETs) with an ultrasmall poly Si channel that has a size of <inline formula> <tex math notation="LaTeX"$5.3\times9$ /tex math>/inline formula> nm<sup>2</sup> and a metal ferroelectric metal insulator semiconductor (MFMIS) are experimentally demonstrated. FETs exhibit a remarkable I<sub>on</sub> I<sub>off</sub> ratio of more than 10<sup>8</sup> We demonstrated stacked channels, double layers, GAA NC FET with a threshold voltage <inline formula> <tex math notation="LaTeX"{V}_{\textit {TH} /tex math>/inline formula> of 0.61 V, and a superior subthreshold behavior with an average and minimum sub <inline formula> <tex math notation="LaTeX"{V}_{\textit {TH} /tex math>/inline formula> slope of 43.85 and 26.84 mV/dec, respectively. An additional ZrO<sub>2</sub> seed layer was inserted under the Hf<inline formula> <tex math notation="LaTeX"$_{{1 {x} /tex math>/inline formula>Zr<sub>x</sub>O<sub>2</sub> layer to improve ferroelectric crystallinity. Thus, the conventional crystallization annealing step can be omitted due to the presence of the orthorhombic phase <inline formula> <tex math notation="LaTeX"{o} /tex math>/inline formula> phase) before further post metal annealing (PMA)
author_names: Po-Yi Kuo

Tien-Sheng Chao
title: Experimental Demonstration of Stacked Gate All Around Poly Si Nanowires Negative Capacitance FETs With Internal Gate Featuring Seed Layer and Free of Post Metal Annealing Process
venue: IEEE Electron Device Letters
year: 2019

abstract: Recently, the solution deposition planarization (SDP) technique for deposition of oxide layer for the IBAD MgO template has attracted more attentions. Although the texturing mechanism of IBAD MgO is still under debate, it is accepted that the seed layer (the one close to the MgO) should fulfill several requirements, such as atomic flatness surface as well as material composition. In this work, in order to clarify the influence of SDP seed layer materials on the texture of IBAD MgO layer, we chose Gd Zr O, Gd<sub>2</sub>O<sub>3</sub> ZrO<sub>2</sub> and Y <sub>2</sub>O<sub>3</sub> as seed layer materials. Atomic force microscopy (AFM) X ray diffractometer (XRD) and reflection high energy electron diffraction (RHEED) were used to illustrate the correlation between the microstructure of the seed layer and the texture of IBAD MgO film. AFM analysis shows that the atomic flatness was achieved on all the SDP films, as evidenced by the RMS value of around 0.3 nm on the 1 x 1 mm<sup>2</sup> grid area. RHEED results show that the poor texture of IBAD MgO is present when using Gd<sub>2</sub>O<sub>3</sub> and ZrO <sub>2</sub> as seed layer. Like Y<sub>2</sub>O<sub>3</sub> the SDP GZO film as a seed layer exhibits good compatibility with IBAD MgO. In addition, the XRD result on Gd Zr O xerogel powder implies that the films mainly consist of nanocrystalline Gd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> which is a crucial feature of an efficient barrier layer. Eventually, a <italic>J</italic><sub>c</sub> value of 1.65 MA*cm<sup> 2</sup> (at 77 K, <italic>s.f./italic> was achieved on a full stack of YBCO/CeO<sub>2</sub>/IBAD MgO/SDP layer/C276 sample.
author_names: Jingyuan Chu

Yue Zhao

Shuiliang Zhen

Guangyue Jiang

Yongchun Chen

Wei Wu

Zhiwei Zhang

Zhiyong Hong

Zhijian Jin
title: Influence of Seed Layer Materials on the Texture of IBAD MgO Layer
venue: IEEE Transactions on Applied Superconductivity
year: 2018