Electrical characterization of atomic-layer-deposited hafnium oxide films from hafnium tetrakis(dimethylamide) and water/ozone: Effects of growth temperature, oxygen source, and postdeposition annealing

The electrical properties of HfO2-based metal-insulator- semiconductor capacitors have been systematically investigated by means of I-V and C-V characteristics, admittance spectroscopy, deep level transient spectroscopy, conductance transient, and flat band voltage transient techniques. Attention is also given to the study of the temperature dependence of the leakage current. HfO2 films were grown on p-type silicon substrates by atomic layer deposition using hafnium tetrakis(dimethylamide) as hafnium precursor, and ozone or water as oxygen precursors. The growth temperature ranged from 150 to 350 °C. Low growth temperatures prevent decomposition and high growth rate, as well as high contamination levels. As a result, the leakage current is lower for lower deposition temperatures. Some of the deposited samples were submitted to a postdeposition annealing at 650 °C in N2 atmosphere, showing a decrease in the leakage current and an increase in the equivalent oxide thickness (EOT), whereas interfacial state density increases and defect density inside the dielectric bulk decreases. Regarding dielectric reliability, in our experimental conditions, HfO 2 layers grown at 150 °C exhibit the largest EOT and breakdown voltage. The electrical behaviour is clearly linked with structural properties, and especially with the formation of an interfacial layer between the HfO 2 layer and the silicon substrate, as well as with the presence of several impurities. © 2013 American Vacuum Society.Peer Reviewe

Comparative analysis of MIS capacitance structures with high-k dielectrics under gamma, 16O and p Radiation

MIS capacitance structures, with Hafnium Oxide, Alumina and nanolaminate as dielectrics were studied under gamma photons Co, 25 MeV oxygen ions and 10 MeV protons radiation using capacitance-voltage (C-V) characterization. The main trend of the results shows that the nanolaminates stack presents the highest levels of hysteresis and stretch-out of the C-V curves, suggesting that interface layers between dielectrics could play a relevant role in the study of the radiation response.Fil: Quinteros, C. P.. Comisión Nacional de Energía Atómica; ArgentinaFil: Sambuco Salomone, Lucas Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Redin, Eduardo Gabriel. Universidad de Buenos Aires; ArgentinaFil: Rafí, J. M.. Consejo Superior de Investigaciones Científicas; EspañaFil: Zabala, M.. Consejo Superior de Investigaciones Científicas; EspañaFil: Faigón, A.. Universidad de Buenos Aires; ArgentinaFil: Palumbo, Félix Roberto Mario. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Campabadal, F.. Consejo Superior de Investigaciones Científicas; Españ

Investigation of nitrogen enriched silicon for particle detectors

This article explores the viability of nitrogen enriched silicon for particle physics application. For that purpose silicon diodes and strip sensors were produced using high resistivity float zone silicon, diffusion oxygenated float zone silicon, nitrogen enriched float zone silicon and magnetic Czochralski silicon. The article features comparative studies using secondary ion mass spectrometry, electrical characterization, edge transient current technique, source and thermally stimulated current spectroscopy measurements on sensors that were irradiated up to a fluence of 1015 neq/cm2. Irradiations were performed with 23 MeV protons at the facilities in Karlsruhe (KIT), with 24 GeV/c protons at CERN (PS-IRRAD) and neutrons at the research reactor in Ljubljana. Secondary ion mass spectrometry measurements give evidence for nitrogen loss after processing, which makes gaining from nitrogen enrichment difficult

10 μ m-thick four-quadrant transmissive silicon photodiodes for beam position monitor application: Electrical characterization and gamma irradiation effects

Silicon photodiodes are very useful devices as X-ray beam monitors in synchrotron radiation beamlines. Owing to Si absorption, devices thinner than 10 μ m are needed to achieve transmission over 90% for energies above 10 keV . In this work, new segmented four-quadrant diodes for beam alignment purposes are fabricated on both ultrathin (10 μ m-thick) and bulk silicon substrates. Four-quadrant diodes implementing different design parameters as well as auxiliary test structures (single diodes and MOS capacitors) are studied. An extensive electrical characterization, including current-voltage (I-V) and capacitance-voltage (C-V) techniques, is carried out on non-irradiated and gamma-irradiated devices up to 100 Mrad doses. Special attention is devoted to the study of radiation-induced charge build-up in diode interquadrant isolation dielectric, as well as its impact on device interquadrant resistance. Finally, the devices have been characterized with an 8 keV laboratory X-ray source at 108 ph/s and in BL13-XALOC ALBA Synchroton beamline with 1011 ph/s and energies from 6 to 16 keV . Sensitivity, spatial resolution and uniformity of the devices have been evaluated.Peer reviewe

2 MeV electron irradiation effects on the electrical characteristics of metal-oxide-silicon capacitors with atomic layer deposited Al<inf>2</inf>O <inf>3</inf>, HfO<inf>2</inf> and nanolaminated dielectrics

The effects of 2 MeV electron irradiation on the electrical characteristics of atomic layer deposited (ALD) high permittivity (high-k) layers of Al 2O3, HfO2 and a nanolaminate of them are evaluated. Metal-oxide-semiconductor capacitors with a nominal dielectric physical thickness of 10 nm were fabricated on different p-type and n-type silicon substrates. The capacitance-voltage (C-V) and current-voltage (I-V) characteristics of the different structures are analyzed as a function of electron irradiation. A progressive negative shift of the C-V characteristics is observed with increasing electron irradiation, indicating the generation of effective positive charges. Similar generation rates for effective trapped charges and interface states are obtained for all the different high-k dielectric layers studied. The hysteresis of the C-V curves after irradiation increases in the case of Al2O3 samples, for HfO 2 decreases while the irradiation has little impact on the hysteresis of the nanolaminate stack. A progressive increase of the leakage current with electron irradiation dose is observed for all the studied dielectrics. The analysis of the current-voltage characteristics measured at different temperatures point to Poole-Frenkel as the dominant conduction mechanism. Under the studied conditions, no impact of electron irradiation fluence on dielectric breakdown voltage has been appreciated. © 2012 Elsevier Ltd. All rights reserved.Peer reviewe

Four-quadrant silicon and silicon carbide photodiodes for beam position monitor applications: Electrical characterization and electron irradiation effects

Silicon photodiodes are very useful devices as X-ray beam monitors in synchrotron radiation beamlines, as well as other astronomy and space applications. Owing to their lower susceptibility to variable temperature and illumination conditions, there is also special interest in silicon carbide devices for some of these applications. Moreover, radiation hardness of the involved technologies is a major concern for high-energy physics and space applications. This work presents four-quadrant photodiodes produced on ultrathin (10 μm) and bulk Si, as well as on SiC epilayer substrates. An extensive electrical characterization has been carried out by using current-voltage (I-V) and capacitance-voltage (C-V) techniques. The impact of different temperature (from -50C to 175C) and visible light conditions on the electrical characteristics of the devices has been evaluated. Radiation effects caused by 2 MeV electron irradiation up to 1×1014, 1×1015 and 1×1016 e/cm2 fluences have been studied. Special attention has been devoted to the study of charge build-up in diode interquadrant isolation, as well as its impact on interquadrant resistance. The study of these electrical properties and its radiation-induced degradation should be taken into account for device applications.Peer reviewe

Gamma and proton irradiation effects and thermal stability of electrical characteristics of metal-oxide-silicon capacitors with atomic layer deposited Al<inf>2</inf>O<inf>3</inf> dielectric

The radiation hardness and thermal stability of the electrical characteristics of atomic layer deposited Al2O3 layers to be used as passivation films for silicon radiation detectors with slim edges are investigated. To directly measure the interface charge and to evaluate its change with the ionizing dose, metal-oxide-silicon (MOS) capacitors implementing differently processed Al2O3 layers were fabricated on p-type silicon substrates. Qualitatively similar results are obtained for degradation of capacitance-voltage and current-voltage characteristics under gamma and proton irradiations up to equivalent doses of 30 Mrad and 21.07 Mrad, respectively. While similar negative charge densities are initially extracted for all non-irradiated capacitors, superior radiation hardness is obtained for MOS structures with alumina layers grown with H2O instead of O3 as oxidant precursor. Competing effects between radiation-induced positive charge trapping and hydrogen release from the H2O-grown Al2O3 layers may explain their higher radiation resistance. Finally, irradiated and non-irradiated MOS capacitors with differently processed Al2O3 layers have been subjected to thermal treatments in air at temperatures ranging between 100 °C and 200 °C and the thermal stability of their electrical characteristics has been evaluated. Partial recovery of the gamma-induced degradation has been noticed for O3-grown MOS structures. This can be explained by a trapped holes emission process, for which an activation energy of 1.38 ± 0.15 eV has been extracted.Peer reviewe

Hot carrier reliability in deep-submicrometer LATID NMOSFETs

The hot-carrier degradation of large angle tilt implanted drain (LATID) NMOSFETs of a 0.35 μm CMOS technology is analysed and compared to the degradation behaviour of standard LDD devices.LATID NMOSFETs are found to exhibit a significant improvement in terms of both, current drivability and hot-carrier immunity. By means of I-V characterisation and charge pumping measurements, the different factors which can be responsible for this improved hot-carrier resistance are investigated. It is shown that this must be attributed to a reduction of the maximum lateral electric field along the channel, but not to a minor generation of physical damage for a given electric field or to a reduced I-V susceptibility to a given amount of generated damage. © 2000 Elsevier Science Ltd. All rights reserved.Peer reviewe

Hot-hole-induced interface states build-up on deep-submicrometer LDD nMOSFETs

The hot-carrier degradation of deep-submicrometer LDD nMOSFETs under different gate-stress regimes is analysed by means of current-voltage and charge pumping characteristics. Interface state generation is found to arise as the major mechanism responsible for device degradation in the whole range of gate regimes studied. The effects of Short Electron and Hole Injection phases on hot-carrier-stressed devices are also analysed. Although SEI phases are found to be an efficient tool for revealing part of the damage generated in stresses at low gate voltages, the performance of a first SHI phase after stress at high gate bias (Vg>Vd/2) results in a significant additional degradation of the devices. This enhanced degradation is attributed to a sudden interface states build-up occurring near the Si/spacer interface only under the first hot-hole injection condition.Peer reviewe

Transconductance increase due to charge trapping during hot-carrier stress of nMOSFETs

Peer reviewe