Browse Prior Art Database

Gate-Controlled Superconductor-Semiconductor Contacts

IP.com Disclosure Number: IPCOM000106195D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 82K

Publishing Venue

IBM

Related People

Gallagher, WJ: AUTHOR [+3]

Abstract

Disclosed is a device that uses a gate to control the properties of the contact between a superconductor and a semiconductor. A gate-controlled Super-Schottky diode is described and demonstrated. Other realizations are also described.

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This is the abbreviated version, containing approximately 52% of the total text.

Gate-Controlled Superconductor-Semiconductor Contacts

      Disclosed is a device that uses a gate to control the
properties of the contact between a superconductor and a
semiconductor.  A gate-controlled Super-Schottky diode is described
and demonstrated.  Other realizations are also described.

      The Super-Schottky diode, a low-noise mm-wave and far-infrared
radiation detector, is based on a superconductor-semiconductor
contact.  Disclosed here is a gated structure that allows the device
impedance to be tuned.  In Fig. 1, the shaded regions are depleted of
carriers and act as insulators.  In this realization, the gate is a
pn junction, with the n-layer in contact with the superconductors.
The resistance of the device is dominated by the contact resistance
between the superconductor electrodes  and the n-type semiconductor
layer, and is controlled by the thickness of the conducting layer
beneath the contact.  In this device, the thickness of the conducting
n-type layer, the difference between the total thickness of
n-material and the width of the n side of the depletion region at the
pn junction, is controlled by the bias on the gate electrode.  For
effective operation, the parasitic series resistance is kept small by
using heavy doping in the n-type region between the superconducting
electrodes or by keeping the distance between these electrodes as
short as possible.  In some cases, in low impedance devices, a
super-current can exist, due to proximity effect coupling between the
electrodes.  This can be suppressed by adding paramagnetic impurities
in the region between the electrodes or by choosing a semiconductor
with a short coherence length.

      This g...