Investigation of the effect of thermal cycling on the device performance of YBa2Cu3O7−δ DC-SQUIDs

Avci, I.; Algul, Berrin Pinar; Bozbey, Ali; Akram, Rizwan; Tepe, Mustafa; Abukay, D.

doi:10.1088/0953-2048/20/10/008

Cited by 2 publications

(2 citation statements)

References 15 publications

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“…The latter has been widely used because of the limitation in the feature size of shadow masks [6]. In both cases, on the other hand, YBCO thin films, particularly the sensitive elements of the devices, such as Josephson junctions, are exposed to high temperatures caused by the deposition system and to chemicals used in the patterning process [7]. Since a YBCO thin film is very sensitive to the temperature in terms of the oxygen content [8] and to some extent a humid environment caused by the lithographic process [9], these additional steps can likely cause significant degradation in the superconducting properties of the final device [10].…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Direct Gold Wire Bonding on Superconducting <inline-formula><tex-math notation="LaTeX">$\mbox{YBa}_{2}\mbox{Cu}_{3}\mbox{O}_{7\mbox{-}x}$</tex-math></inline-formula> Thin Films and Devices

Avci

Kuran

Uzun

2015

IEEE Trans. Appl. Supercond.

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The performance analysis of direct gold (Au) wire bonding on YBa 2 Cu 3 O 7-x (YBCO) thin films was performed. In a number of applications, YBCO thin films and devices are wire bonded on chip carriers or printed circuit boards for further electronic connections via the metallization of the contact pads of YBCO thin films. Although metallization for contact wiring is generally performed by thermal evaporation or sputtering at room temperature, the surface of a film is generally exposed to high temperatures by evaporated material or sputtering plasma. Moreover, an additional lithographic process (i.e., the application of a photoresist, baking, developing, and dry or wet etching) is necessary after the metal layer deposition in order to define contact pads. Since the superconducting properties of YBCO thin films and Josephson junctions are very sensitive to temperature and a humid environment, the metallization and additional lithographic processes during the fabrication cause significant degradation in the performance of the devices. In order to eliminate these additional steps, we performed a direct wire bonding process on YBCO thin films. Films of various thicknesses were deposited onto (100) SrTiO 3 (STO) substrates by direct-current magnetron sputtering, and 20-μm-wide meander-type microbridges were patterned. The contact pads of the devices were wire bonded onto chip carriers by a thermosonic wedge bonder without using any metallization layer. The reliability and performance analyses of the bonds were performed under several aggressive thermal cycling conditions from liquid nitrogen (LN, 77 K) up to 450 K. The superconducting properties of the samples were then analyzed by means of resistance-temperature (R-T ) and current-voltage (I-V ) measurements. A resistance model was developed for the bonding layout, and a specific contact resistivity was derived as ∼3 × 10 −6 Ω · cm 2 .

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Section: Introductionmentioning

confidence: 99%

Performance Analysis of Direct Gold Wire Bonding on Superconducting <inline-formula><tex-math notation="LaTeX">$\mbox{YBa}_{2}\mbox{Cu}_{3}\mbox{O}_{7\mbox{-}x}$</tex-math></inline-formula> Thin Films and Devices

Avci

Kuran

Uzun

2015

IEEE Trans. Appl. Supercond.

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“…Even though the fabrication complexity of YBCO Josephson junctions has been simplified with bicrystal technology [11][12][13], the reliability of YBCO based SQUIDs is still the major challenge for many applications such as magneto-cardiography (MCG), susceptometry and non-destructive evaluation (NDE) [14][15][16]13]. The major limitations of YBCO SQUIDs are their relatively high 1/f noise levels, low output voltage modulation depths ( V) and low stability in time during room temperature storage and thermal cycles [4,6,17]. Most of them are related to the structural properties of YBCO thin films and junctions on them.…”

Section: Introductionmentioning

confidence: 99%

Signal performance of DC-SQUIDs with respect to YBCO thin film deposition rate

Avci

Algul

Akram

et al. 2009

Sensors and Actuators A: Physical

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a b s t r a c tThe signal performances of YBa 2 Cu 3 O 7−ı (YBCO) direct current superconducting quantum interference devices (DC-SQUIDs) have been investigated as a function of the thin film structure affected by the growth process. YBCO thin films of 200 nm thicknesses were deposited by DC magnetron sputtering using different deposition rates between 1.0 nm/min and 2.0 nm/min onto 24• bicrystal SrTiO 3 (STO) substrates. The thin film samples were subsequently analyzed by XRD and AFM in order to determine their crystalline structures and surface morphologies respectively. The 67 pH directly coupled DC-SQUIDs with 4 m-wide bicrystal Josephson junctions were fabricated, and characterized with respect to their device performances. The variations in the critical current (I c ), the voltage modulation depth ( V) and the noise performance of DC-SQUIDs were reported. The SQUIDs having relatively low deposition rate of 1.0 nm/min was observed to have larger voltage modulation depth as well as higher critical current than that of the samples having larger rate of 2.0 nm/min. The better noise performances were observed as the film deposition rate decreases. The results were associated with the thin film structure and the SQUID characteristics.

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Investigation of the effect of thermal cycling on the device performance of YBa₂Cu₃O_7−δ DC-SQUIDs

Cited by 2 publications

References 15 publications

Performance Analysis of Direct Gold Wire Bonding on Superconducting <inline-formula><tex-math notation="LaTeX">$\mbox{YBa}_{2}\mbox{Cu}_{3}\mbox{O}_{7\mbox{-}x}$</tex-math></inline-formula> Thin Films and Devices

Performance Analysis of Direct Gold Wire Bonding on Superconducting <inline-formula><tex-math notation="LaTeX">$\mbox{YBa}_{2}\mbox{Cu}_{3}\mbox{O}_{7\mbox{-}x}$</tex-math></inline-formula> Thin Films and Devices

Signal performance of DC-SQUIDs with respect to YBCO thin film deposition rate

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