Change in carbon nanofiber resistance from ambient to vacuum

The electrical properties of carbon nanofibers (CNFs) can be affected by adsorbed gas species. In this study, we compare the resistance values of CNF devices in a horizontal configuration in air and under vacuum. CNFs in air are observed to possess lower current capacities compared to those in vacuum. Further, Joule heating due to current stressing can result in desorption of gas molecules responsible for carrier trapping, leading to lower resistances and higher breakdown currents in vacuum, where most adsorbed gaseous species are evacuated before any significant re-adsorption can occur. A model is proposed to describe these observations, and is used to estimate the number of adsorbed molecules on a CNF device

Effectiveness and Safety of Leukocytapheresis Therapy for Ulcerative Colitis

Leukocytapheresis (LCAP) was performed in seven patients with moderate or severe active ulcerative colitis (UC) at the Koga Hospital. LCAP was considered as having been effective in all seven patients (excellent clinical response in five and moderate clinical response in two patients). The excellent or moderate clinical response continued throughout maintenance LCAP in three of seven patients. None of the patients required discontinuation of LCAP, despite the appearance of some side effects, including facial redness, low-grade fever, discomfort, headache and hypotension during the therapy. The results of this study indicate that LCAP may be a safe and effective intensive and maintenance therapy for UC

Change in carbon nanofiber resistance from ambient to vacuum

The electrical properties of carbon nanofibers (CNFs) can be affected by adsorbed gas species. In this study, we compare the resistance values of CNF devices in a horizontal configuration in air and under vacuum. CNFs in air are observed to possess lower current capacities compared to those in vacuum. Further, Joule heating due to current stressing can result in desorption of gas molecules responsible for carrier trapping, leading to lower resistances and higher breakdown currents in vacuum, where most adsorbed gaseous species are evacuated before any significant re-adsorption can occur. A model is proposed to describe these observations, and is used to estimate the number of adsorbed molecules on a CNF device

High-frequency behavior of one-dimensional nanocarbons

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are potential materials for the most advanced silicon devices and circuits due to their excellent electrical properties such as high current capacity and tolerance to electromigration. In addition, at high frequencies, these materials exhibit transport behavior which holds promise for applications as on-chip interconnects

RF characteristics of one-dimensional nanocarbons

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are potential materials for the most advanced silicon devices and circuits due to their excellent electrical properties such as high current capacity and tolerance to electromigration. In addition, at high frequencies, these materials exhibit transport behavior which holds promise for applications as on-chip interconnects

Carbon Nanofiber Interconnect RF Characteristics Improvement with Deposited Tungsten Contacts

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are potential materials for high-performance electronic devices and circuits due to their light weight and excellent electrical properties such as high current capacity and tolerance to electromigration. In addition, at high frequencies, these materials exhibit transport behavior which holds special promise for applications as on-chip interconnects. Contact resistance at CNF-metal interface is a major factor in limiting the electrical performance of CNF interconnects at all frequencies. In this paper, it is demonstrated that the contact resistance can be minimized and the high-frequency characteristics much enhanced by depositing tungsten on CNF-metal electrode contacts

Improved RF Characteristics of Carbon Nanotube Interconnects with Deposited Tungsten Contacts

Carbon Nanofibers (CNFs) grown by Plasma Enhanced Chemical Vapor Deposition (PECVD) are potential next-generation interconnect materials due to their high current capacity. We designed and fabricated a test structure for RF characterization of CNF interconnects up to 50 GHz and developed a compact circuit model based on their results. Their devices showed that the contact impedance between the CNF and the electrode contacts can be reduced to some extent by Joule heating from dc current stressing, and can be further improved if a suitable metal is deposited on the electrode contacts. we fabricated CNF interconnects with Au electrodes, and deposit W at the contacts. W deposits are produced by two techniques: Electron Beam Induced Deposition (EBID) with WF6 as the source gas, and Ion beam Induced Depositions (IBID). The electrical characteristics of these CNF interconnect test devices obtained with these two methods are compared from dc up to 50 GHz and the circuit parameters including the contact impedance are extracted. Carbon Nanofibers (CNFs) grown by Plasma Enhanced Chemical Vapor Deposition (PECVD) are potential next-generation interconnect materials due to their high current capacity. We designed and fabricated a test structure for RF characterization of CNF interconnects up to 50 GHz and developed a compact circuit model based on their results. Their devices showed that the contact impedance between the CNF and the electrode contacts can be reduced to some extent by Joule heating from dc current stressing, and can be further improved if a suitable metal is deposited on the electrode contacts. we fabricated CNF interconnects with Au electrodes, and deposit W at the contacts. W deposits are produced by two techniques: Electron Beam Induced Deposition (EBID) with WF6 as the source gas, and Ion beam Induced Depositions (IBID). The electrical characteristics of these CNF interconnect test devices obtained with these two methods are compared from dc up to 50 GHz and the circuit parameters including the contact impedance are extracted

Electron-beam and ion-beam-induced deposited tungsten contacts for carbon nanofiber interconnects

Ion-beam-induced deposition (IBID) and electron-beam-induced deposition (EBID) with tungsten (W) are evaluated for engineering electrical contacts with carbon nanofibers (CNFs). While a different tungsten-containing precursor gas is utilized for each technique, the resulting tungsten deposits result in significant contact resistance reduction. The performance of CNF devices with W contacts is examined and conduction across these contacts is analyzed. IBID-W, while yielding lower contact resistance than EBID-W, can be problematic in the presence of on-chip semiconducting devices, whereas EBID-W provides substantial contact resistance reduction that can be further improved by current stressing. Significant differences between IBID-W and EBID-W are observed at the electrode contact interfaces using high-resolution transmission electron microscopy. These differences are consistent with the observed electrical behaviors of their respective test devices