Browse Prior Art Database

Multilayer Insulation for Josephson Technology

IP.com Disclosure Number: IPCOM000046101D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Gasser, M: AUTHOR [+2]

Abstract

A multilayer insulation structure is proposed consisting of alternately arranged layers of silicon oxide and of a material, such as Nb2O5, that has a finite electric conductivity at device fabrication temperatures but that provides for insulation at cryogenic device operation temperatures. The proposed structure provides for high-yield, pinhole-free insulation.

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Multilayer Insulation for Josephson Technology

A multilayer insulation structure is proposed consisting of alternately arranged layers of silicon oxide and of a material, such as Nb2O5, that has a finite electric conductivity at device fabrication temperatures but that provides for insulation at cryogenic device operation temperatures. The proposed structure provides for high-yield, pinhole-free insulation.

The figure illustrates how the proposed structure can be employed in Nb-Pb Josephson junction devices where a pinhole-free insulation between the counter electrode and the overlying control lines is required. The insulation sandwich structure Il-IL-I2 can, e.g., be formed by the following layers: SiO (2000), Nb2O5 (1000), and SiO (2000). SiO can be replaced by other suitable materials, such as SiO2 . Also, the IL layer does not need to consist of Nb-oxide alone but may be a composite of Nb + Nb2O5 . Again, alternate materials, such as Al ( + Al2O3), Ti (+ TiO2), Ta (+ Ta2O5), can be applied. The number of sandwiched layers can also be varied particularly for applications where the device capacitance is critical: the resulting total capacitance between counter electrode and control lines becomes smaller when the number of layers is increased.

During fabrication, the IL-material chosen has a finite electric conductivity sufficient to collect and ground electrostatic charges that may otherwise, due to electrostatic discharges, lead to the destruction of the insul...