Response to Comment on 'High quality YBa2Cu3O7 Josephson junctions made by direct electron beam writing'

S. K. Tolpygo; S. Shokhor; B. Nadgorny; J.-Y. Lin; M. Gurvitch; A. Bourdillon; S. Y. Hou; Julia M. Phillips

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• Publié par: Nifong
• Nombre de lectures: 15
• Langue: English

Extrait

Response to “Comment on ‘High quality YBa2Cu307 Josephson junctions
made by direct electron beam writing’ ” [Appl. Phys. Let-t. 64, 3190
(i9Wl
S. K. Tolpygo, S. Shokhor, B. Nadgorny, J.-Y. Lin, and M. Gurvitch
Department of Physics, State University of New Ydrk at Stony Brook, Stony Brook, New York 11794-3800
A. Bourdillon
Deuartment of Materials Science and Enaineerina, State Universify of New York at Stony Brook,
St&y Brook, New York 11794-2275 -
S. Y. Hou and Julia M. Phillips
AT&T Bell Laboratories, Murray Hill, New Jersey 07974
(Received 2 December 1993)
In response to Tinchevr we would like to acknowledge eters used in e-beam writing as well as definitive results,
that the idea of using a focused electron beam in a scanning leaving little doubt that the weak links obtained by this tech-
electron microscope to damage a narrow region across a nique are indeed Josephson junctions. We would like to take
high-T, thin film bridge was indeed expressed in his 1990 this opportunity to reference one more article, omitted in our
article.’ However, contrary to Tinchev’s claim that “the first letter, reported by us at a conference in 1991 and published
successfully fabricated junctions by this technique were de- in 1992, it included our preliminary bridge modification data
scribed in that publication,” no such data or any other data and Monte Carlo simulation of electron trajectories for dif-
on e-beam irradiated samples were presented there at all. ferent beam energies.12
Since we are discussing this issue, we should note that We thank J. C. Humphreys and S. S. Tinchev for bring-
others published similar thoughts. The possibility of creating ing their early insight to our attention.
a weak link by damaging a substrate by a focused electron
beam and then growing a film on it was discussed by
‘S. S. ‘Hnchev, Appl. Phys. Lett. 64, 3190 (1994). Broers.3 Humphreys et al. in their 1988 article4 suggested
*S. S. Tinchev, Supercond. Sci. Technol. 3, 500 (1990). that intense focused electron beams can be used to cut
3A. N. Broers, IBM J. Res. Develop. 32, 502 (1988).
nanometer-wide lines in the amorphous phase of 4C. J. Humpreys, D. J. Eaglesham, N. M. Alford, M. A. Harmer, and J. D.
YBa&&O,, so that subsequent processing into superconduc- Birchall, Inst. Phys. Conf. 2, 217 (1988).
‘C. J. Humpreys, in Encyclopedia Mater. Sci. Eng. 2, 1299 (1990). tor could lead to creation of weak links with appropriately
‘C. J. Humpreys (private communication). small scale comparable to coherence length. These methods,
‘D. F. Moore, Proceedings of the Extended Abstracts of the 2nd Workshop
however, could not be utilized in their original form. Hum- on High Temperature Superconducting Electron Devices, Shikabe,
phreys further mentioned a possibility of local oxygen re- Hokkaido, Japan, June 7-9 (Research and Development for Future Elec-
tron Devices, Tokyo, 1989). moval by the same technique5 and subsequently filed for a
‘M. Gurvitch, Official AT@T Notebook, entry of August 1979, case No. UK patent based on these ideas.6 No data were presented on 38788, witnessed by M. A. Washington.
such weak links in Refs. 4-6 nor, to the best of our knowl- ‘S. Tolpygo, S. Shokhor, B. Nadgorny, J. Y. Lin, M. Gurvitch, A.
edge, in any of the referenced authors’ subsequent publica- Bourdillon, S. Y. Hou, and Julia M. Phillips, Appl. Phys. Lett. 63, 1696
(1993). tions. The same method was suggested by Moore in 1989.7
I’M. Gurvitch, J. Macaulay, Z. Bao, B. Bi, S. Han, J.-Y. Lin, J. Lukens, B. One of us (M.G.) entertained the idea of direct focused Nadgorny, and J. M. Phillips, M. P. Siegel, and E. S. Hellman, Extended
electron beam writing of Josephson superconducting circuits Abstracts of 3rd FED Workshop on High-Temperature Superconducting
Electron Devices, May 15-17, 1991, Kumamoto, Japan (Research and in A-15 superconductors such as NbsSn back in 1978-1979,8
Development Assocaiation for Future Electron Devices, Tokyo, 1991) p. and later renewed his interest in this technique upon learning
162; M. Gurvitch, S. K. Tolpygo, B. Nadgorny, S. Shokhor, J.-Y. Lin, F.
of easy oxygen desorption from YBa&usO,, and the possi- Tafuri, J. M. Macaulay, A. Bourdillon, S. Hou, and J. M. Phillips, in
bility of hole drilling in fluorides and oxides with intense Proceedings of the 3rd International Workshop on Tunneling Phenomena
in high and low T, Superconductors, October l-4, 1991, Italy. (World electron beams, which was described at a Bell Labs 1987
Scientific, Singapore, 1993). seminar by Steven D. Berger. At Stony Brook, a project to
‘IA. J. Pauza, Z. Barber, A. M. Campbell, J. E!. Evetts, R. E. Somekh, D. F.
make Josephson junctions by this method started in 1989 Moore, and A. N. Broers, Extended Abstrates of Third International Su-
after we submitted a proposal to the Science and Technology perconductive Electronics Conference, 25-27 June, 1991, Glasgow, Scot-
land (Glasgow, United Kingdom, 1991) p. 352; A. J. Pauza, A. M. Cam- Foundation of the State of New York.
bell, D. F. Moore, R. E. Somekh, and A. N. Broers, IEEE Trans. Appl. In our letter9 we chose to refer to more recent article;,
Supercond. 3, 2405 (1993).
both OUE?~ and that of the Cambridge group” which contain rzJ. M. Macaulay, Z. Bao, B. Bi, M. Gurvitch, S. Han, J. Y. Lin, J. Lukens,
detailed discussions of the method, procedure, and param- and B. Nadgomy, Superlattices and Microstructures 11, 211 (1992).
Appl. Phys. Lett. 64 (23), 6 June 1994 0003-6951/94/64(23)/3191/1/$6.00 (B 1994 American Institute of Physics 3191
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