J. Semicond. > 2014, Volume 35 > Issue 8 > 083004
|

SEMICONDUCTOR MATERIALS

Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient

Yuqiong Chu, Zongliang Huo, Yulong Han, Guoxing Chen, Dong Zhang, Xinkai Li and Ming Liu

+ Author Affiliations

 Corresponding author: Huo Zongliang, Email:huozongliang@ime.ac.cn; Liu Ming, Email:liuming@ime.ac.cn

DOI: 10.1088/1674-4926/35/8/083004

PDF

Abstract: The retention characteristics of electrons and holes in hafnium oxide with post-deposition annealing in a N2 or O2 ambient were investigated by Kelvin probe force microscopy. The KFM results show that compared with the N2 PDA process, the O2 PDA process can lead to a significant retention improvement. Vertical charge leakage and lateral charge spreading both played an important role in the charge loss mechanisms. The retention improvement is attributed to the deeper trap energy. For electrons, the trap energy of the HOS structure annealed in a N2 or O2 ambient were determined to be about 0.44 and 0.49 eV, respectively. For holes, these are about 0.34 and 0.36 eV, respectively. Finally, the electrical characteristics of the memory devices are demonstrated from the experiment, which agreed with our characterization results. The qualitative and quantitative determination of the charge retention properties, the possible charge decay mechanism and trap energy reported in this work can be very useful for the characterization of hafnium charge storage devices.

Key words: KFM, HfO2, retention



[1]
Kim K. From the future Si technology perspective:challenges and opportunities. Electron Devices Meeting, 2010, 1(1):1 http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=5703274
[2]
Wang Y Q, Hwang W S, Zhang G, et al. Electrical characteristics of memory devices with a high-k HfO2 trapping layer and dual SiO2/Si3N4 tunneling layer. IEEE Trans Electron Devices, 2007, 54(10):2700 http://ieeexplore.ieee.org/document/4317755/
[3]
You H W, Cho W J. Charge trapping properties of the HfO2 layer with various thicknesses for charge trap flash memory applications. Appl Phys Lett, 2010, 96(9):093506 doi: 10.1063/1.3337103
[4]
Yuan C L, Chan M Y, Lee P S, et al. Al2O3 nanocrystals embedded in amorphous Lu2O3 high-k gate dielectric for floating gate memory application. J Phys:Conference Series, 2007, 61(1):1312 http://adsabs.harvard.edu/abs/2007JPhCS..61.1312Y
[5]
Ding S J, Zhang D W, Wang L K. Atomic-layer-deposited Al2O3-HfO2 laminated and sandwiched dielectrics for metal-insulator-metal capacitors. J Phys D:Appl Phys, 2007, 40(4):1072 doi: 10.1088/0022-3727/40/4/023
[6]
Maikap S, Rahaman S Z, Tien T C, et al. Nanoscale (EOT = 5.6 nm) nonvolatile memory characteristics using n-Si/SiO2/HfAlO nanocrystal/Al2O3/Pt capacitors. Nanotechnology, 2008, 19(43):435202 doi: 10.1088/0957-4484/19/43/435202
[7]
Sugizaki T, Kohayashi M, Ishidao M, et al. Novel multi-bit SONOS type flash memory using a high-k charge trapping layer. Symposium on VLSI Technology, 2003:27 http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=1221069
[8]
Spiga S, Driussi F, Lamperti A. Experimental and simulation study of the program efficiency of HfO2 based charge trapping memories. Solid-State Device Research Conference (ESSDERC), 2010:408 http://ieeexplore.ieee.org/abstract/document/5618194/
[9]
Zhu Chenxin, Yang Rong, Huo Zongliang, et al. Investigation of charge trap and loss characteristics for charge trap memory by electrostatic force microscopy. Non-Volatile Memory Technology Symposium (NVMTS), 2011:1 http://ieeexplore.ieee.org/document/6137099/
[10]
Chowdhury N A, Garg R, Misra D, et al. Charge trapping and interface characteristics of thermally evaporated HfO2. Appl Phys Lett, 2004, 85(15):3290 doi: 10.1063/1.1805708
[11]
Ryan J T, Yu L C, Han J H, et al. A new interface defect spectroscopy method. IRPS, 2011:203 http://ieeexplore.ieee.org/document/5872242/
[12]
Uren M J. The properties of individual Si/SiO2 defects and their link to 1/f noise. Mater Sci Forum, 1992, 83-87:1519 doi: 10.4028/www.scientific.net/MSF.83-87
[13]
Girard P. Electrostatic force microscopy:principles and some applications to semiconductors. Nanotechnology, 2001, 12(4):485 doi: 10.1088/0957-4484/12/4/321
[14]
Tzeng S D, Gwo S. Charge trapping properties at silicon nitride/silicon oxide interface studied by variable-temperature electrostatic force microscopy. J Appl Phys, 2006, 100(2):023711 doi: 10.1063/1.2218025
[15]
Baik S J, Lim K S. Lateral redistribution of trapped charges in nitride/oxide/Si (NOS) investigated by electrostatic force microscopy. Nanoscale, 2011, 3:2560 doi: 10.1039/c1nr10104h
[16]
Chen Yong, Zhao Jianming, Han Dedong, et al. Extraction of equivalent oxide thickness for HfO2 high k gate dielectrics. Chinese Journal of Semiconductors, 2006, 27(5):852
Fig. 1.  Schematic sample structure and KFM analysis method (a) charge injection with contact mode and (b) contact potential differences (CPDs) measurement.

DownLoad: Full-Size Img PowerPoint
Fig. 2.  The measured CPDs profiles after injection of electrons and holes of samples annealed in (a) N$_{2}$ and (b) O$_{2}$ ambient (c) injected electron and hole density in 0 s and after 7560 s.

DownLoad: Full-Size Img PowerPoint
Fig. 3.  Normalized electron and hole densities ($\sigma _{\rm T}$ /$\sigma _{\rm T 0})$ evolution versus the elapsed time corresponding to samples annealed in a N$_{2}$ and O$_{2}$ ambient, which present the overall performance of retention. }

DownLoad: Full-Size Img PowerPoint
Fig. 4.  Charge density line profiles (dot lines) and their fitted curve using Eq. (1) (thin lines) of devices annealed in N$_{2}$ ambient.

DownLoad: Full-Size Img PowerPoint
Fig. 5.  (a) CPD decay profiles of the sample with HfO$_{2}$ trapping layer at 90 ℃ and 25 ℃. (b) ln($\sigma _{\rm I})$-$t$ plots, which are converted from CPD peak values by assuming charges are distributed at the interface, where $E_{\rm T}$ is the effective trap energy. (c) Relationship between $\tau T^{2}$ (unit: sK$^{2})$ and $1/T$ (unit: K$^{-1})$, where $\alpha $ is the combination of temperature independent constants, and $e_{\rm bb}$ is the direct tunneling of electrons through the oxide from HfO$_{2}$ conduction band into the silicon conduction band.

DownLoad: Full-Size Img PowerPoint
Fig. 6.  The high-frequency (100 kHz) $C$-$V$ hysteresis of the two samples under $\pm $15 V sweep voltage.

DownLoad: Full-Size Img PowerPoint
Fig. 7.  Data retention properties at 25 ℃ and 85 ℃ with an identical initial $V_{\rm fb}$ of samples annealed in N$_{2}$ and O$_{2}$ ambients.

DownLoad: Full-Size Img PowerPoint
Fig. 8.  Gate leakage current properties at data retention properties at 25 ℃ and 85 ℃ of samples annealed in N2 and O2 ambients.

DownLoad: Full-Size Img PowerPoint

Table 1.   Extracted diffusion coefficients for different samples.

Table 2.   Extracted trap energy levels for different samples. Unit: eV
[1]
Kim K. From the future Si technology perspective:challenges and opportunities. Electron Devices Meeting, 2010, 1(1):1 http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=5703274
[2]
Wang Y Q, Hwang W S, Zhang G, et al. Electrical characteristics of memory devices with a high-k HfO2 trapping layer and dual SiO2/Si3N4 tunneling layer. IEEE Trans Electron Devices, 2007, 54(10):2700 http://ieeexplore.ieee.org/document/4317755/
[3]
You H W, Cho W J. Charge trapping properties of the HfO2 layer with various thicknesses for charge trap flash memory applications. Appl Phys Lett, 2010, 96(9):093506 doi: 10.1063/1.3337103
[4]
Yuan C L, Chan M Y, Lee P S, et al. Al2O3 nanocrystals embedded in amorphous Lu2O3 high-k gate dielectric for floating gate memory application. J Phys:Conference Series, 2007, 61(1):1312 http://adsabs.harvard.edu/abs/2007JPhCS..61.1312Y
[5]
Ding S J, Zhang D W, Wang L K. Atomic-layer-deposited Al2O3-HfO2 laminated and sandwiched dielectrics for metal-insulator-metal capacitors. J Phys D:Appl Phys, 2007, 40(4):1072 doi: 10.1088/0022-3727/40/4/023
[6]
Maikap S, Rahaman S Z, Tien T C, et al. Nanoscale (EOT = 5.6 nm) nonvolatile memory characteristics using n-Si/SiO2/HfAlO nanocrystal/Al2O3/Pt capacitors. Nanotechnology, 2008, 19(43):435202 doi: 10.1088/0957-4484/19/43/435202
[7]
Sugizaki T, Kohayashi M, Ishidao M, et al. Novel multi-bit SONOS type flash memory using a high-k charge trapping layer. Symposium on VLSI Technology, 2003:27 http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=1221069
[8]
Spiga S, Driussi F, Lamperti A. Experimental and simulation study of the program efficiency of HfO2 based charge trapping memories. Solid-State Device Research Conference (ESSDERC), 2010:408 http://ieeexplore.ieee.org/abstract/document/5618194/
[9]
Zhu Chenxin, Yang Rong, Huo Zongliang, et al. Investigation of charge trap and loss characteristics for charge trap memory by electrostatic force microscopy. Non-Volatile Memory Technology Symposium (NVMTS), 2011:1 http://ieeexplore.ieee.org/document/6137099/
[10]
Chowdhury N A, Garg R, Misra D, et al. Charge trapping and interface characteristics of thermally evaporated HfO2. Appl Phys Lett, 2004, 85(15):3290 doi: 10.1063/1.1805708
[11]
Ryan J T, Yu L C, Han J H, et al. A new interface defect spectroscopy method. IRPS, 2011:203 http://ieeexplore.ieee.org/document/5872242/
[12]
Uren M J. The properties of individual Si/SiO2 defects and their link to 1/f noise. Mater Sci Forum, 1992, 83-87:1519 doi: 10.4028/www.scientific.net/MSF.83-87
[13]
Girard P. Electrostatic force microscopy:principles and some applications to semiconductors. Nanotechnology, 2001, 12(4):485 doi: 10.1088/0957-4484/12/4/321
[14]
Tzeng S D, Gwo S. Charge trapping properties at silicon nitride/silicon oxide interface studied by variable-temperature electrostatic force microscopy. J Appl Phys, 2006, 100(2):023711 doi: 10.1063/1.2218025
[15]
Baik S J, Lim K S. Lateral redistribution of trapped charges in nitride/oxide/Si (NOS) investigated by electrostatic force microscopy. Nanoscale, 2011, 3:2560 doi: 10.1039/c1nr10104h
[16]
Chen Yong, Zhao Jianming, Han Dedong, et al. Extraction of equivalent oxide thickness for HfO2 high k gate dielectrics. Chinese Journal of Semiconductors, 2006, 27(5):852

    • Search

    Advanced Search >>

    GET CITATION

    shu

    Export: BibTex EndNote

    Article Metrics

    Article views: 2350 Times PDF downloads: 13 Times Cited by: 0 Times

    History

    Received: 10 January 2014 Revised: 10 March 2014 Online: Published: 01 August 2014

    Catalog

      Email This Article

      User name:
      Email:*请输入正确邮箱
      Code:*验证码错误
      Send
      Article Navigation >  Journal of Semiconductors  > 2014  >  35(8): 083004
      Yuqiong Chu, Zongliang Huo, Yulong Han, Guoxing Chen, Dong Zhang, Xinkai Li, Ming Liu. Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient[J]. Journal of Semiconductors, 2014, 35(8): 083004. doi: 10.1088/1674-4926/35/8/083004 ****Y Q Chu, Z L Huo, Y L Han, G X Chen, D Zhang, X K Li, M Liu. Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient[J]. J. Semicond., 2014, 35(8): 083004. doi: 10.1088/1674-4926/35/8/083004.
      Citation:
      Yuqiong Chu, Zongliang Huo, Yulong Han, Guoxing Chen, Dong Zhang, Xinkai Li, Ming Liu. Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient[J]. Journal of Semiconductors, 2014, 35(8): 083004. doi: 10.1088/1674-4926/35/8/083004 ****
      Y Q Chu, Z L Huo, Y L Han, G X Chen, D Zhang, X K Li, M Liu. Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient[J]. J. Semicond., 2014, 35(8): 083004. doi: 10.1088/1674-4926/35/8/083004.
      shu

      Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient

      DOI: 10.1088/1674-4926/35/8/083004

      • Laboratory of Nano-Fabrication and Novel Devices Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China

      Funds:

      the National Natural Science Foundation of China 61176073

      the MOST 2011CBA00600

      the MOST 2010CB934200

      Project supported by the MOST (Nos. 2010CB934200, 2011CBA00600) and the National Natural Science Foundation of China (No.61176073)

      More Information

      Catalog

        Journal of Semiconductors © 2017 All Rights Reserved   京ICP备05085259号-2

        /

        DownLoad:  Full-Size Img  PowerPoint
        Return
        Return