  Superconducting circuits based on hybrid InAs Josephson Junctions (JJs) play
a starring role in the design of fast and ultra-low power consumption
solid-state quantum electronics and exploring novel physical phenomena.
Conventionally, 3D substrates, 2D quantum wells (QWs), and 1D nanowires (NWs)
made of InAs are employed to create superconductive circuits with hybrid JJs.
Each platform has its advantages and disadvantages. Here, we proposed the
InAs-on-insulator (InAsOI) as a groundbreaking platform for developing
superconducting electronics. An epilayer of semiconductive InAs with different
electron densities was grown onto an InAlAs metamorphic buffer layer,
efficiently used as a cryogenic insulator to decouple adjacent devices
electrically. JJs with various lengths and widths were fabricated employing Al
as a superconductor and InAs with different electron densities. We achieved a
switching current density of 7.3 uA/um, a critical voltage of 50-to-80 uV, and
a critical temperature equal to that of the superconductor used. For all the
JJs, the switching current follows a characteristic Fraunhofer pattern with an
out-of-plane magnetic field. These achievements enable the use of InAsOI to
design and fabricate surface-exposed Josephson Field Effect Transistors with
high critical current densities and superior gating properties.
