This study clarifies the influence of single-layer(TiN,HfN,W)and bi-layer(HfN/TiN,W/TiN)bottom electrodes(BEs)on the ferroelectric performance and reliability of the 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)(HZO)thin films.A ...This study clarifies the influence of single-layer(TiN,HfN,W)and bi-layer(HfN/TiN,W/TiN)bottom electrodes(BEs)on the ferroelectric performance and reliability of the 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)(HZO)thin films.A smaller thermal expansion coefficient in HfN or W imposes higher in-plane tensile stress on the HZO thin films,facilitating the polar orthorhombic(o-)phase fraction and enhancing remanent polarization(P_(r)).However,thicker interfacial layers formed when HfN or W single-layer BE and HZO contacted directly,leading to excessive leakage current and degraded ferroelectric performance.These excessive interfacial layers were effectively suppressed by inserting a thin(5 nm-20 nm)TiN layer on the HfN or W BEs.As a result,the HZO thin films on the HfN/TiN and W/TiN bi-layer BEs decrease the HZO grain size,facilitating the o-phase formation(increasing P_(r))and lowering the film's coercive field.However,the higher surface roughness of the W/TiN bi-layer BEs induced excessive leakage current and reliability degradation.In contrast,the HfN BEs with a 10-or 20-nm-thick upper TiN layer lower the surface roughness of the BEs,thereby eliminating the adverse effects.As a result,the HfN 40 nm/TiN 10 nm/HZO/TiN stack exhibited enhanced ferroelectric performance up to 10^(9)switching cycles with a lower cycling field of 2.7 MV/cm than the TiN 50 nm/HZO/TiN stack with a cycling field of 3.7 MV/cm.展开更多
Phase change memory （PCM） has been regarded as a promising candidate for the next generation of nonvolatile memory. To decrease the power required to reset the PCM cell, titanium nitride （TIN） is preferred to be u...Phase change memory （PCM） has been regarded as a promising candidate for the next generation of nonvolatile memory. To decrease the power required to reset the PCM cell, titanium nitride （TIN） is preferred to be used as the bottom electrode of PCM due to its low thermal and suitable electrical conductivity. However, during the manufacture of PCM cell in 40 nm process node, abnormally high and discrete distribution of the resistance of TiN bottom electrode was found, which might be induced by the surface oxidation of TiN bottom electrode during the photoresist ashing process by oxygen plasma. In this work, we have studied the oxidation of TiN and found that with the increasing oxygen plasma ashing time, the thickness of the TiO2 layer became thicker and the state of the TiO2 layer changed from amorphous to crystalline, respectively. The resistance of TiN electrode contact chain with 4-5 nm TiO2 layer was confirmed to be almost three-orders of magnitude higher than that of pure TiN electrode, which led to the failure issue of PCM cell. We efficiently removed the oxidation TiO2 layer by a chemical mechanical polishing （CMP） process, and we eventually recovered the resistance of TiN bottom electrode from 1×10^5Ω/via back to 6×10^2 Ωvia and successfully achieved a uniform resistance distribution of the TiN bottom electrode.展开更多
The Bi4Zr0.5Ti2.5O12 (BZT) thin films were fabricated on the LaNiO3 bottom electrode using sol-gel method. The structure and morphology of the films were character-ized using X-ray diffraction, AFM and SEM. The result...The Bi4Zr0.5Ti2.5O12 (BZT) thin films were fabricated on the LaNiO3 bottom electrode using sol-gel method. The structure and morphology of the films were character-ized using X-ray diffraction, AFM and SEM. The results show that the films have a perovskite phase and dense microstructure. The 2Pr and 2Vc of the Pt/BZT/LaNiO3 capacitor are 28.2 μC/cm2 and 14.7 V respectively at an applied voltage of 25 V. After the switching of 1×1010 cycles, the Pr value decreases to 87% of its pre-fatigue val-ues. The dielectric constant (ε) and the dissipation factor (tanδ) of the BZT thin films are about 204 and 0.029 at 1 kHz, respectively. The films show good insulating behavior according to the test of leakage current. The clockwise C-V hysteresis curve observed shows that the Pt/BZT/LaNiO3 structure has a memory effect be-cause of the BZT film’s ferroelectric polarization.展开更多
With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures wa...With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures was adopted in the fabrication course. Seen from the fabrication structure of enhanced petaling cold cathode,the bar conducting electrode and the petaling bottom electrode were fabricated with the sintered silver slurry on cathode glass faceplate. The luminescence image with green phosphor was displayed for the sealed enhanced petaling cold cathode FED. The measured results showed that the enhanced petaling cold cathode had good field emission performance. The enhanced petaling cold cathode FED possessed low turn-on electric-field of 1. 95 V /μm,large emission current of 1 389. 6 μA,and high luminance brightness of 1 520 cd /m2 .展开更多
基金supported by the National Research Foundation of Korea(Grant No.2020R1A3B2079882).
文摘This study clarifies the influence of single-layer(TiN,HfN,W)and bi-layer(HfN/TiN,W/TiN)bottom electrodes(BEs)on the ferroelectric performance and reliability of the 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)(HZO)thin films.A smaller thermal expansion coefficient in HfN or W imposes higher in-plane tensile stress on the HZO thin films,facilitating the polar orthorhombic(o-)phase fraction and enhancing remanent polarization(P_(r)).However,thicker interfacial layers formed when HfN or W single-layer BE and HZO contacted directly,leading to excessive leakage current and degraded ferroelectric performance.These excessive interfacial layers were effectively suppressed by inserting a thin(5 nm-20 nm)TiN layer on the HfN or W BEs.As a result,the HZO thin films on the HfN/TiN and W/TiN bi-layer BEs decrease the HZO grain size,facilitating the o-phase formation(increasing P_(r))and lowering the film's coercive field.However,the higher surface roughness of the W/TiN bi-layer BEs induced excessive leakage current and reliability degradation.In contrast,the HfN BEs with a 10-or 20-nm-thick upper TiN layer lower the surface roughness of the BEs,thereby eliminating the adverse effects.As a result,the HfN 40 nm/TiN 10 nm/HZO/TiN stack exhibited enhanced ferroelectric performance up to 10^(9)switching cycles with a lower cycling field of 2.7 MV/cm than the TiN 50 nm/HZO/TiN stack with a cycling field of 3.7 MV/cm.
基金Project supported by the National Key Basic Research Program of China(Nos.2010CB934300,2013CBA01900,2011CBA00607,2011CB932804)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA09020402)+2 种基金the National Integrate Circuit Research Program of China(No.2009ZX02023-003)the National Natural Science Foundation of China(Nos.61176122,61106001,61261160500,61376006)the Science and Technology Council of Shanghai(Nos.12nm0503701,13DZ2295700,12QA1403900,13ZR 1447200)
文摘Phase change memory （PCM） has been regarded as a promising candidate for the next generation of nonvolatile memory. To decrease the power required to reset the PCM cell, titanium nitride （TIN） is preferred to be used as the bottom electrode of PCM due to its low thermal and suitable electrical conductivity. However, during the manufacture of PCM cell in 40 nm process node, abnormally high and discrete distribution of the resistance of TiN bottom electrode was found, which might be induced by the surface oxidation of TiN bottom electrode during the photoresist ashing process by oxygen plasma. In this work, we have studied the oxidation of TiN and found that with the increasing oxygen plasma ashing time, the thickness of the TiO2 layer became thicker and the state of the TiO2 layer changed from amorphous to crystalline, respectively. The resistance of TiN electrode contact chain with 4-5 nm TiO2 layer was confirmed to be almost three-orders of magnitude higher than that of pure TiN electrode, which led to the failure issue of PCM cell. We efficiently removed the oxidation TiO2 layer by a chemical mechanical polishing （CMP） process, and we eventually recovered the resistance of TiN bottom electrode from 1×10^5Ω/via back to 6×10^2 Ωvia and successfully achieved a uniform resistance distribution of the TiN bottom electrode.
基金Supported by Natural Science Foundation of Hubei Province (Grant No. 2004ABA082)
文摘The Bi4Zr0.5Ti2.5O12 (BZT) thin films were fabricated on the LaNiO3 bottom electrode using sol-gel method. The structure and morphology of the films were character-ized using X-ray diffraction, AFM and SEM. The results show that the films have a perovskite phase and dense microstructure. The 2Pr and 2Vc of the Pt/BZT/LaNiO3 capacitor are 28.2 μC/cm2 and 14.7 V respectively at an applied voltage of 25 V. After the switching of 1×1010 cycles, the Pr value decreases to 87% of its pre-fatigue val-ues. The dielectric constant (ε) and the dissipation factor (tanδ) of the BZT thin films are about 204 and 0.029 at 1 kHz, respectively. The films show good insulating behavior according to the test of leakage current. The clockwise C-V hysteresis curve observed shows that the Pt/BZT/LaNiO3 structure has a memory effect be-cause of the BZT film’s ferroelectric polarization.
基金National Natural Science Foundations of China(No.60976058,No.61274078)Natural Science Research Project of Henan Province Education Department,China(No.2009B510019)
文摘With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures was adopted in the fabrication course. Seen from the fabrication structure of enhanced petaling cold cathode,the bar conducting electrode and the petaling bottom electrode were fabricated with the sintered silver slurry on cathode glass faceplate. The luminescence image with green phosphor was displayed for the sealed enhanced petaling cold cathode FED. The measured results showed that the enhanced petaling cold cathode had good field emission performance. The enhanced petaling cold cathode FED possessed low turn-on electric-field of 1. 95 V /μm,large emission current of 1 389. 6 μA,and high luminance brightness of 1 520 cd /m2 .
