Please wait a minute...
Chin. Phys. B, 2015, Vol. 24(9): 093301    DOI: 10.1088/1674-1056/24/9/093301
ATOMIC AND MOLECULAR PHYSICS Prev   Next  

Characteristics of Nb/Al superconducting tunnel junctions fabricated using ozone gas

Masahiro Ukibe, Go Fujii, Masataka Ohkubo
Nanoelectronics Research Institute (nano), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
Abstract  To improve the energy resolution (ΔE) of Nb/Al superconducting tunnel junctions (STJs), an ozone (O3) oxidation process has been developed to fabricate a thin defect-free tunnel barrier that simultaneously shows high critical current JC > 1000 A/cm2 and high normalized dynamic resistance RDA > 100 MΩ · μm2, where A is the size of the STJ. The 50-μm2 STJs produced by O3 exposure of 0.26 Pa· min with an indirect spray of O3 gas, which is a much lower level of exposure than the O2 exposure used in a conventional O2 oxidation process, exhibit a maximum JC = 800 A/cm2 and a high RDA= 372 MΩ · μm2. The 100-pixel array of the 100-μm2 STJs produced using the same O3 oxidation conditions exhibits a constant leak current Ileak = 14.9 ± 3.2 nA at a bias point around Delta /e (where e is half the energy gap of an STJ), and a high fabrication yield of 87%. Although the Ileak values are slightly larger than those of STJs produced using the conventional O2 oxidation process, the STJ produced using O3 oxidation shows a ΔE = 10 eV for the C-Kα line, which is the best value of our Nb/Al STJ x-ray detectors.
Keywords:  Nb/Al superconducting tunnel junctions      high critical current density      high energy resolution      ozone  
Received:  05 December 2014      Revised:  28 April 2015      Accepted manuscript online: 
PACS:  33.20.Kf (Visible spectra)  
  33.70.Jg (Line and band widths, shapes, and shifts)  
Corresponding Authors:  Masahiro Ukibe     E-mail:  ukibe-m@aist.go.jp

Cite this article: 

Masahiro Ukibe, Go Fujii, Masataka Ohkubo Characteristics of Nb/Al superconducting tunnel junctions fabricated using ozone gas 2015 Chin. Phys. B 24 093301

[1] Ukibe M, Shiki S, Kitajima Y and Ohkubo M 2012 Jpn. J. Appl. Phys. 51 010115
[2] Fons P, Tampo H V. Kolobov A, Ohkubo M, Niki S, Tominaga J, Carboni R, Boscherini F and Friedrich S 2006 Phys. Rev. Lett. 96 045504
[3] Friedrich S, Funk T, Drury O, Labov S E and Cramer S P 2002 Rev. Sci. Instrum. 73 1629
[4] Ohkubo M, Shiki S, Ukibe M, Matsubayashi N, Kitajima Y and Nagamachi S 2012 Sci. Rep. 2 831
[5] Ukibe M, Fujii G and Ohkubo M 2014 J. Low Temp. Phys. 176 142
[6] Miller R E, Mallison W H, Kleinsasser A W, Delin K A and Macedo E M 1993 Appl. Phys. Lett. 63 1423
[7] Youssef A E, Švindrych Z, Hadač J and Jansů Z 2007 WDS's 07 Proceedings (Part III) 48
[8] Ukibe M, Kushino A, Chen Y and Ohkubo M 2007 X-ray Spectr. 36 260
[9] http://www.iwatani.co.jp/jpn/div/ing_wem/ele_gas/cylinder/main.html
[10] Horvath M, Bilitzky L and Huttner J 1985 Ozone (New York: Elsevier)
[11] Kato H, O'Rourke B E and Suzuki R 2014 JJAP Conf. Proc. 2 011302
[12] Shiki S, Ukibe M, Kitajima Y and Ohkubo M 2012 J. Low Temp. Phys. 167 748
[13] Mears C A, Labov S E and Barfknecht A T 1993 Appl. Phys. Lett. 63 2961
[14] Goldie D J, Brink P L, Patel C, Booth N E and Salmon G L 1994 Appl. Phys. Lett. 64 3169
[15] Schlosser D M, Lechner P, Luts G, Niculae A, Soltau H, Struder L, Eckhardt E, Hermenau K, Schaller G, Schopper G, Jaritschin O, Liebel A, Simsek A, Fiorini C and Longini A 2010 Nucl. Instrum. Methods Phys. Res., Sect. A 624 270
[1] Ozone oxidation of 4H-SiC and flat-band voltage stability of SiC MOS capacitors
Zhi-Peng Yin(尹志鹏), Sheng-Sheng Wei(尉升升), Jiao Bai(白娇), Wei-Wei Xie(谢威威), Zhao-Hui Liu(刘兆慧), Fu-Wen Qin(秦福文), and De-Jun Wang(王德君). Chin. Phys. B, 2022, 31(11): 117302.
[2] Improvement of the high-κ/Ge interface thermal stability using an in-situ ozone treatment characterized by conductive atomic force microscopy
Ji-Bin Fan(樊继斌), Xiao-Jiao Cheng(程晓姣), Hong-Xia Liu(刘红侠), Shu-Long Wang(王树龙), Li Duan(段理). Chin. Phys. B, 2017, 26(8): 087701.
[3] Performance and reliability improvement of La2O3/Al2O3 nanolaminates using ultraviolet ozone post treatment
Ji-Bin Fan(樊继斌), Hong-Xia Liu(刘红侠), Bin Sun(孙斌), Li Duan(段理), Xiao-Chen Yu(于晓晨). Chin. Phys. B, 2017, 26(5): 057702.
[4] Modeling the interaction of nitrate anions with ozone and atmospheric moisture
A. Y. Galashev. Chin. Phys. B, 2015, 24(10): 103601.
[5] UV-ozone-treated MoO3 as the hole-collecting buffer layer for high-efficiency solution-processed SQ:PC71BM photovoltaic devices
Yang Qian-Qian (杨倩倩), Yang Dao-Bin (杨道宾), Zhao Su-Ling (赵谡玲), Huang Yan (黄艳), Xu Zheng (徐征), Gong Wei (龚伟), Fan Xing (樊星), Liu Zhi-Fang (刘志方), Huang Qing-Yu (黄清雨), Xu Xu-Rong (徐叙瑢). Chin. Phys. B, 2014, 23(3): 038405.
[6] Equivalent oxide thickness scaling of Al2O3/Ge metal-oxide-semiconductor capacitors with ozone post oxidation
Sun Jia-Bao (孙家宝), Yang Zhou-Wei (杨周伟), Geng Yang (耿阳), Lu Hong-Liang (卢红亮), Wu Wang-Ran (吴汪然), Ye Xiang-Dong (叶向东), David Zhang Wei (张卫), Shi Yi (施毅), Zhao Yi (赵毅). Chin. Phys. B, 2013, 22(6): 067701.
[7] Computer simulation study of the cluster destruction of stratospheric ozone by bromine
A. E. Galashev, O. R. Rakhmanova. Chin. Phys. B, 2012, 21(11): 113602.
[8] Potential energy surfaces of ozone in the ground state
Shao Ju-Xiang(邵菊香), Zhu Zheng-He(朱正和), Huang Duo-Hui(黄多辉) Wang Jun(王君), Cheng Xin-Lu(程新路), and Yang Xiang-Dong(杨向东). Chin. Phys. B, 2007, 16(9): 2650-2655.
No Suggested Reading articles found!