Martin Claus

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Downscaling of the contact length Lc of a side-contacted carbon nanotube field-effect transistor (CNTFET) is challenging because of the rapidly increasing contact resistance as Lc falls below 20-50 nm. If in agreement with existing experimental results, theoretical work might answer the question, which metals yield the lowest CNT-metal contact resistance(More)
Recent experimental investigations of sub-10nm carbon nanotube (CNT) field-effect transistors (FETs) promote CNT based 1D-electronics as a candidate for a future aggressively scaled transistor technology. However, the ballistic transport within the 1D semiconducting CNT channel is largely determined by charge injection from the contacts rendering reliable(More)
This paper gives a short overview on our recent investigations towards a multiscale modeling and simulation framework for metal-CNT interfaces. We employ three simulation approaches with well defined interfaces. For the simulation at device level we make use of a recently developed wave-function based effective-mass Schrödinger-Poisson solver which(More)
HF noise parameters were measured and modeled for the first time for wafer-scale manufacturable CNTFETs. These first multi-tube multi-finger CNTFETs exhibit still relatively high values for the minimum noise figure (NFmin = 3.5 dB at 1 GHz). Based on detailed compact modeling, the origin of this noise can be explained by the existence of the parasitic(More)
Time-dependent quantum simulations are used to rigorously identify non-quasi-static (NQS) effects in Carbon nanotube transistors. A complete physics-based small signal equivalent circuit is derived which captures important NQS effects for circuit design and simulation. This model agrees well with high-frequency measurements. Additionally, the impact of(More)
Covalent functionalization of carbon nanotubes (CNTs) might be an option to optimize the behavior of CNT field effect transistors (FETs) [1] (despite all related technological problems). In principle, the atoms or molecules used for functionalizing are placed randomly along the CNT or they are high-ordered in decoration patterns. Here, only high-ordered(More)
Depletion-mode CNTFETs are being fabricated successfully with useable tolerances and compact models are now available for circuit design and engineering. This paper presents the first design study of mixers based on those devices. The impact of peculiar device features and parasitic on analog and RF circuits is discussed in detail and the cascode mixer is(More)
A time-dependent effective-mass SchrödingerPoisson solver is used to study the frequency dependence of the gate capacitance of a short Schottky-barrier carbon nanotube field-effect transistor (CNTFET). A delayed (re)charging of the channel causes a (non-quasi-static) drop of the gate capacitance for higher frequencies on a characteristic scale, which can be(More)
An efficient and reliable numerical simulator for carbon nanotube field effect transistors suitable for device optimization and compact model development is presented. The simulator is based on a Schrödinger-Poisson solver and an efficient adaptive integration scheme for the charge and the current along the nanotube. While suitable error estimators for(More)
Top gate, global back gate and buried gate CNTFET structures with a channel length of 5.9 nm are studied in the scope of the 2026 ITRS requirements. The studies are performed using a numerical device simulator. Figures of merit and performance parameters such as the switching speed, the switching energy, I<sub>on</sub>/I<sub>off</sub>-ratio, among others,(More)