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Development of DLTS Microscopy in Nano-resolution

Research Project

Project/Area Number 08555003
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section展開研究
Research Field Applied materials science/Crystal engineering
Research InstitutionTHE UNIVERSITY OF TOKYO

Principal Investigator

MAEDA Koji  The Univ.of Tokyo, Dept.of Ap-plied Physics, Professor, 大学院・工学系研究科, 教授 (10107443)

Co-Investigator(Kenkyū-buntansha) NAGAMURA Toshihiko  UNISOKU Inc., Sci.Instrum.De-velopment Lab., Director, 科学機器開発研究所, 所長
MERA Yutaka  The Univ.of Tokyo, Dept.of Ap-plied Physics, Research Associate, 大学院・工学系研究科, 助手 (40219960)
Project Period (FY) 1996 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥19,600,000 (Direct Cost: ¥19,600,000)
Fiscal Year 1998: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1997: ¥12,000,000 (Direct Cost: ¥12,000,000)
Fiscal Year 1996: ¥7,200,000 (Direct Cost: ¥7,200,000)
KeywordsDLTS / Microscopy / Non-contact / Surface Photovoltage / Deep Levels / STM / Transient Response / Nano
Research Abstract

Surface photovoltage (SPV) exhibits a delayed decay when a deep level trap is present in the depletion layer beneath the surface. Based on this idea, we have developed a new scheme of Deep Level Transient Spectroscopy (DLTS) combined with Scanning Tunneling Microscopy (STM) in which the STM tips are used to probe the transient of SPV on chopping the light causing the SPV.
(a)Preliminary experiments using GaAs samples in air showed that temperature spectra similar to optical DLTS spectra can be obtained and the spatial distribution of the DLTS signal can be imaged in high resolution of several tens nm.
(b)Theoretical considerations revealed that spatial resolution of STM-DLTS is determined by the electrostatic surface potential affected by the charge of the carrier trapped at the deep level center beneath the surface. The resolution in the absence of charge screening is approximately 3 times the depth of the trap while that is 1.4 times when the 2-dimensional electron gas formed at the su … More rface screens the trapped charge.
(c)Isothermal measurements that were tried to avoid the draw-back of the extremely high resolution due to thermal shift of STM tips with respect to sample position revealed that a more stable STM unit (thermal shift-free) and high-speed measurements are necessary to circumvent artifacts arising from the current feed-back control.
(d)A thermal shift-free STM stage of our original design was constructed and its performance was assessed. Thermal drifts the order of 2 times lower than the conventional stages and thermal shift 1/200 of those stages were achieved.
(e)Ultra-high vacuum experiments using GaAs samples showed that apparent transient due to thermal expansion of STM tips on light illumination can be avoided when the time regime is reduced well shorter than 0.1 ms.
(f)Current preamplifier with 10^8 V/A gain and a bandwidth as wide as 100 kHz was successfully assembled. From these results, we were able to confirm the feasibility of practical applications of STM-DLTS to nano-structured sample systems. Less

Report

(4 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • 1996 Annual Research Report
  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] S.Sugita,Y.Mera and K.Maeda: "Origin of Low Frequency Noise and 1/f Fluctuations in STM Tunneling Current" J.Appl.Phys.79. 4166-4173 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Maeda,M.Uota and Y.Mera: "Spatially Resolved Deep Level Transient Spectroscopy using a Scanning Tunneling Microscope" Mater.Sci.Eng.B. 42. 127-132 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Inoue,K.Suzuki,H.Ama-suga,Y.Mera and K.Maeda: "Electronically enhanced kink motion on 30° partial dislocations in directly observed by plan-view high resolution electron microscopy" J.Appl.Phys.83. 1953-1957 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Y.Nakamura,Y.Mera and K.Maeda: "A Reproducible Method to Fabricate Atomically Sharp Tips for Scanning Tunneling Microscopy" Rev.Sci.Instrum.submitted. (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] S.Sugita, Y.Mera and K.Maeda: "Origin of Low Frequency Noise and 1/f Fluctuations in STM Tun-neling Current" J.Appl.Phys.79. 4166-4173 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Maeda, M.Uota and Y.Mera: "Spatially Resolved Deep Level Transient Spectroscopy using a Scanning Tunneling Microscope" Mater.Sci.Eng.B. 42 (1-3). 127-132 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Inoue, K.Suzuki, H.Amasuga, Y.Mera and K.Maeda: "Electronically enhanced kink motion on 30 partial dislocations in Ge directly observed by plan-view high resolution electron microscopy" J.Appl.Phys.83 (4). 1953-1957 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Y.Nakamura, Y.Mera and K.Maeda: "A Reproducible Method to Fabricate Atomically Sharp Tips for Scanning Tunneling Microscopy" Rev.Sci.Instrum. (submitted). (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Y.Nakamura: "A Reproducible Method to Fabricate Atomically Sharp Tips for Scanning Tunneling Microscopy" Rev.Sci.Instrum.(submitted). (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] M.Inoue et al.: "Electronically enhanced kink motion on 30° partial dislocations in Ge directly observed by plan-view high resolution electron microscopy" J.Appl.Phys.83-4. 1953-1957 (1998)

    • Related Report
      1997 Annual Research Report
  • [Publications] K.Maeda,M.Uota and Y.Mera: "Spatially Resolved Deep Level Transient Spectroscopy using a Scanning Tunneling Microscope" Mater.Sci.Eng.B. 42(1-3). 127-132 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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