A. Matiss

High-Frequency Measurements on InAs Nanowire Field-Effect Transistors Using Coplanar Waveguide Contacts

In this paper, a 50-μm-pitch coplanar waveguide pattern for on-wafer high-frequency measurements on nanowire FET is used. The contact structure exhibits relatively large parasitic elements in comparison to the intrinsic device making a precise deembedding both necessary and challenging. A single InAs nanowire FET with a large gate length of 1.4 μm possesses after deembedding a maximum stable gain higher than 30 dB and a maximum oscillation frequency of 15 GHz. The gate length scaling of the nanowire transistor is modeled using the experimental transconductance data of a set of transistors and an analytical model. On this basis, both the device performance and the expectation of high-frequency measurements at small gate lengths are discussed.

High frequency characterisation of single InAs nanowire field-effect transistors

We report on a first RF characterisation of single InAs nanowire channel field-effect-transistors. The nanowires with about 30 nm diameter are transferred to a carrier substrate and contacted with a coplanar waveguide pad configuration with a pitch down to 50 mum. Magnesium oxide as well as SiNx are used as gate dielectric for high performance MISFET type field-effect-transistors. Small signal scattering parameter measurements have been performed on-wafer. The nanowire FET exhibit an ultra-small intrinsic gate-source capacitance Cgs down to a few hundred ato Farad, making a careful de-embedding of the data indispensable. First measurements have shown a maximum stable gain higher than 30 dB at low frequency and a maximum oscillation frequency of 15 GHz.

Sub-Nanosecond Pulse Generation using Resonant Tunneling Diodes for Impulse Radio

The application of resonant tunneling diodes (RTD) for generation of Gaussian-like monocycles and modified Hermite pulses of 2nd order for ultrawideband (UWB) impulse radio is investigated in this paper. A circuit concept employing a pin-photodiode and two RTD based monostable bistable threshold logic elements (MOBILE) is introduced. The circuit generates, depending on a digital optical input signal, arbitrary pulse cycles at the output of the circuit. Based on the measurement result of a single MOBILE, simulations are presented that show the capability of the proposed circuit to generate pulses like single Gaussian pulses, Gaussian monocycles, and 2nd-order modified Hermite pulses. Experimental verification of positive and negative gaussian pulses with a width of 100 ps is demonstrated for a pulse repetition rate of 13.2 Gpulses/s.

Design and modelling of a III/V mobile-gate with optical input on a silicon substrate

The co-integration of III/V devices such as InGaAsP PIN diode and an (In)AlAs/In(Ga)As Resonant Tunnelling Diodes with state-of-the-art silicon NMOS transistors is studied. The III/V devices layers are epitaxially grown and fabricated on silicon substrates for the extraction of model parameters. The performance of a potentially low-cost optical receiver circuit on silicon is simulated using HSPICE up to 10 Gb/s.

Coplanar Contact Pattern for single InAs Nanowire FET

We report on the development of coplanar contact pattern for the RF-characterisation of nanoscaled devices. A contact layout exhibiting a low parasitic capacitance is developed using electrostatic field theory calculations. The improved pad- and coupling capacitance has been experimentally verified based on scattering parameter measurements and small signal parameter extraction of a single nanowire transistor.

Large-Signal Performance of Resonant Tunnelling Diodes in K-Band Oscillators

The large signal behaviour of resonant tunnelling diodes (RTD) in K-band oscillators is investigated in order to optimize the RF-output power of RTD-based voltage controlled oscillators. Circuit simulations based on a scaleable large-signal RTD model are presented and different approaches to increase the RF-power are proposed. A new differential RTD-VCO-circuit in InP RTD/HBT technology with a wide tuning range is introduced, employing balanced RTD-pairs.

Low-Temperature DC and RF Measurement and Modelling of InGaAs-InAlAs Resonant Tunneling Diodes down to 15 K

The influence of temperature on bias dependent small-signal equivalent circuit components of a resonant tunneling diode (RTD) is investigated from 290 K down to 15 K. The RTD model based on bias dependent parasitic elements and the quantum capacitance as well as the quantum conductance is fitted to both, on-wafer DC and RF S-parameter measurements from 45 MHz to 40 GHz over a bias range of 0 V to 0.80 V. For the full temperature range, good agreement between extracted and measured parameters is shown

Monostable-Bistable Threshold Logic Elements in a fully complementary optical receiver circuit for high frequency applications

A fully complementary optical receiver design is presented utilizing two Monostable-Bistable Threshold Logic Elements, consisting of four Resonant Tunneling Diodes and a pin-photodetector in one circuitry. By complementary on and off switching of the two Monostable-Bistable Logic Elements it is possible to double the sampling rate of the optically generated photocurrent. Measurements on fabricated circuits have shown functionality up to 13.2 Gbit/s.

InP-HEMT-TIA with Differential Optical Input Using Vertical High Topology Pin-Diodes

A monolithically integrated combination of high electron mobility transistors and high responsivity (1.0 A/W) vertical pin-diodes have been used in optical synchronous quadrature phase-shift keying transimpedance amplifier design for 40 Gbit/s transmission.