In this letter we report on high-frequency measurements on vertically standing III-V nanowire wrap-gate MOSFETs (metal-oxide-semiconductor field-effect transistors). The nanowire transistors are fabricated from InAs nanowires that are epitaxially grown on a semi-insulating InP substrate. All three terminals of the MOSFETs are defined by wrap around contacts. This makes it possible to perform high-frequency measurements on the vertical InAs MOSFETs. We present S-parameter measurements performed on a matrix consisting of 70 InAs nanowire MOSFETs, which have a gate length of about 100 nm. The highest unity current gain cutoff frequency, f(t), extracted from these measurements is 7.4 GHz and the maximum frequency of oscillation, f(max), is higher than 20 GHz. This demonstrates that this is a viable technique for fabricating high-frequency integrated circuits consisting of vertical nanowires.
Organ-on-chip systems
are promising new
in vitro
research tools in medical,
pharmaceutical, and biological research.
Their main benefit, compared to standard cell culture platforms, lies
in the improved
in vivo
resemblance of the cell culture
environment. A critical aspect of these systems is the ability to
monitor both the cell culture conditions and biological responses
of the cultured cells, such as proliferation and differentiation rates,
release of signaling molecules, and metabolic activity. Today, this
is mostly done using microscopy techniques and off-chip analytical
techniques and assays. Integrating
in situ
analysis
methods on-chip enables improved time resolution, continuous measurements,
and a faster read-out; hence, more information can be obtained from
the developed organ and disease models. Integrated electrical, electrochemical,
and optical sensors have been developed and used for chemical analysis
in lab-on-a-chip systems for many years, and recently some of these
sensing principles have started to find use in organ-on-chip systems
as well. This perspective review describes the basic sensing principles,
sensor fabrication, and sensor integration in organ-on-chip systems.
The review also presents the current state of the art of integrated
sensors and discusses future potential. We bring a technological perspective,
with the aim of introducing in-line sensing and its promise to advance
organ-on-chip systems and the challenges that lie in the integration
to researchers without expertise in sensor technology.
We demonstrate a vertical InAs nanowire MOSFET integrated on Si substrate with an extrinsic peak cut-off frequency of 103 GHz and a maximum oscillation frequency of 155 GHz. The transistor has a transconductance of 730 mS/mm and is based on arrays of nanowires with gateall-around and high-κ gate dielectric. Furthermore, small-signal modeling shows a ∼80% reduction of the total parasitic gate capacitance when the metal pad overlap in the transistors is reduced through additional patterning.
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