1,721,216 research outputs found
Characterization of low temperature photo-assisted metal-organic chemical vapor deposited copper films using hexafluoroacetylacetonate copper(I) trimethylvinylsilane as precursor
No full text[[abstract]]This work demonstrated for the first time low temperature copper (Cu) film deposition by photo-assisted metal-organic chemical vapor deposition (photo-assisted MOCVD) using hexafluoroacetylacetonate copper(l) trimethylvinylsilane (referred to as Cu(hfac)(tmvs)) as precursor. This work found that photo-assisted MOCVD Cu films can be deposited on TaN/tetra-ethylorthosilicate(TEOS)-oxide/Si but not on TEOS-oxide/Si wafers at temperatures as low as 100 degrees C. Cu films grown by photo-assisted MOCVD from Cu(hfac)(tmvs) at 125 degrees C exhibit good qualities, including acceptable electromigration lifetime, lower carbon contamination at the Cu film surface, and excellent step-coverage and trench-filling abilities. (c) 2004 Elsevier B.V. All rights reserved.[[note]]SC
Radiation hardness comparison of MOS capacitors using tungsten polycide and cobalt polycide as gate electrode materials
No full text[[abstract]]In this letter, we investigate the radiation hardness of metal-oxide-semiconductor (MOS) capacitors with tungsten polycide (WSix) and those with cobalt polycide (CoSi2) as gate electrode materials. COSi2 has been considered as a gate/contact material for MOS devices in 0.18 mu m integrated.circuit fabrication due to its low resistivity and good thermal stability. However, we found that MOS capacitors with a COSi2 gate electrode exhibited an increase in radiation-induced interface trap density shift of more than one order of magnitude, and more than eighteen times larger in radiation-induced flatband voltage shifts compared with those with the WSix gate electrode, after 1 Mrad Co-60 gamma-ray irradiation under no applied bias.[[note]]SC
Post-breakdown oxide voltage oscillation in thin SiO2 under nano-scaled repetitive ramped voltage stress
No full text[[abstract]]The post-breakdown behaviour of a thin SiO2 layer on the same oxide location under repetitive ramped voltage stress using a conductive atomic force microscopy is reported for the first time. It was observed that the oxide voltage on the same spot decreases and then oscillates between certain smaller values after it is broken down. A mechanism based on permanent trap generation in the oxide accompanied with trap capture radius and trap energy level relaxation is proposed to explain the oxide voltage oscillation phenomenon.[[note]]SC
The impact of implantation sequence on the characterization of n-MOSFET's with gate oxide grown on nitrogen-implanted Si substrate
No full text[[abstract]]Both of the nitrogen implantation and threshold-voltage adjustment implantation introduce dopant atoms near the SiO2/Si interface during the fabrication of n-channel metal-oxide-semiconductor field-effect transistor (n-MOSFET's) with gate oxide grown on nitrogen implanted silicon substrate. This work examined the impact of implantation sequence on the characterization of n-MOSFET's with gate oxide grown on nitrogen implanted silicon substrate. It is found that the sequence of nitrogen implantation and boron implantation affects both the electrical characteristics and hot-carrier properties of n-MOSFET's. It is found that no channel mobility degradation, less interface state density, lower subthreshold leakage current and better hot-carrier resistance can be achieved in the n-MOSFET's if the threshold-voltage adjustment implantation is performed after the nitrogen implantation during the gate oxide preparation. However lower channel mobility, higher interface state density, higher subthreshold leakage current and less hot-carrier resistance were observed if the implantation sequence was reversed. (C) 2002 Elsevier Science Ltd. All rights reserved.[[note]]SC
Stress reliability comparison of metal-oxide-semiconductor devices with COSi2 and TiSi2 gate electrode
No full text[[abstract]]Conventionally, CoSi2 is considered to be a better choice than TiSi2 for integrated circuit Fabrication due to its lower resisitivity and better thermal stability. In this letter we compare for the first time the stress reliability of metal-oxide-semiconductor (MOS) devices with CoSi2 and TiSi2 as gate electrode materials. We found that the use of' TiSi2 as a gate electrode material can provide a better stress resistance than CoSi2, when negatively-biased constant current stress and constant voltage stress are applied.[[note]]SC
Two-trap-assisted tunneling model for post-breakdown I-V characteristics in ultrathin silicon dioxide
No full text[[abstract]]This paper investigated the degradation and breakdown characteristics of an ultrathin silicon dioxide film by using conductive atomic force microscopy (C-AFM) with repetitive ramped voltage stress (RVS). Two-step oxide degradation was determined from the measured current-voltage (I-V) characteristics and topographies. In the first step, bond breaking and negative-charge accumulation near the SiO2/Si interface causes oxide thinning and an effective increase in SiO2/Si barrier height. In this step, hard breakdown (HBD) actually does not occur until permanent damage is produced within the oxide during the second step after several times of repetitive RVS. The permanent damage produced inside the oxide film is in the form of traps, which will cause the crooked I-V curves and a larger I-V shift along the voltage axis. A two-trap-assisted tunneling (TTAT) model was proposed to explain the postbreakdown I-V behaviors. In this model, two isolated traps were generated in the oxide after breakdown. The trap location of the nearer traps determines the bending of the postbreakdown I-V curves and that of the farther traps causes the I-V oxide voltage shift along the voltage axis. The model fits the measured postbreakdown I-V curves well when the locations of both the nearer trap and the farther trap are chosen correctly.[[note]]SC
Deuterium post-metallization anneal of electrochemical-plated Cu film deposited on different barrier materials
No full text[[abstract]]In this paper, we report on electrochemical-plated (ECP) copper (Cu) film characterizations with different (Ta, TaN and TiN) barrier materials subjected to post-metallization-annealing (PMA) in deuterium (D-2) under various annealing conditions. For comparison, post-metallization-anneal of the ECP Cu film in pure nitrogen (N-2) and forming gas (20% hydrogen+80% nitrogen) were also performed. We used four-point probe to determine the sheet resistance. Scanning electron microscopy was used to examine the surface morphology of the after-annealed ECP Cu films. X-ray-diffraction (XRD) analysis was used to inspect the texture of the ECP Cu films before and after PMA. The deuterium distribution in the barrier layer was determined by using the secondary ion mass spectroscopy depth profile analysis. We found that under appropriate PMA conditions, the sheet resistance of ECP Cu films deposited on TaN barrier was the lowest after D-2 PMA when compared with those deposited on TiN and Ta barriers. (C) 2004 Elsevier B.V. All rights reserved.[[note]]SC
Investigation into the modelling of field-effect carrier mobility in disordered organic semiconductors
No full text[[abstract]]Organic semiconductors have attracted significant interest because of their potential application in electronic devices. One of the most important parameters in such an application is the carrier mobility, which is low when compared with inorganic semiconductors. In the past, significant effort has been spent to produce high mobility organic semiconductors, even though the best room temperature value reported is only a few cm(2)/V.s. In the work, the field-effect carrier mobility in organic semiconductors is examined by correlating reported data for pentacene with simulations based on the correlated disorder model. Using the rms width of the density of states (DOS) as the main variable, a good match between data and simulations has been produced. The results suggested that the carrier mobihty in disordered organic semiconductors could be solely dependent on sigma, the rms width of the DOS. The rather small value of sigma used in the calculations pointed to the need for a better understanding into the transport mechanism within this regime. Other fitting parameters affected the carrier mobility included the site spacing and the barrier height, both of which were capable of changing the carrier mobility. A more careful examination revealed that there were physical constraints limiting the values of these parameters.[[note]]SC
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