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Item type:Publication, Access status: without files , Post hard breakdown conduction in MOS capacitors with silicon and aluminum oxide as dielectric(2008-04-01); ; I-V curves as a function of voltage and temperature of MOS capacitors with silicon oxide and aluminum oxide after dielectric breakdown are presented. A different temperature behavior in accumulation is observed. The samples with aluminum oxide show an entirely positive temperature dependence, whereas the samples with silicon oxide have a crossover of the temperature dependent curves. This difference of the two sample types is attributed to the charge distribution according to the material of the breakdown spot, silicon for the case of silicon oxide, and aluminum for aluminum oxide. Thus, in the first case, a p-n junction is formed while a Schottky contact is created in the latter case. Atlas simulations and TEM analysis are presented that confirm this hypothesis.Publicationtype: Journal Article13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Model for the voltage and temperature dependence of the soft breakdown current in ultrathin gate oxides(American Institute of Physics (AIP), 2005); ; ; The voltage and temperature dependence of the soft breakdown conduction mechanism in metal-oxide-semiconductor capacitors and transistors with ultrathin dielectric layers is investigated. A physical derivation of the quantum point contact model and its parameters is presented, which incorporates the smearing of the Fermi function at the electrodes as well as the effect of thermal vibrations of the constriction's bottleneck. The model also takes into account the boundary conditions at the two ends of the breakdown path by considering the semiconductor band bending occurring in the nondamaged surrounding device area. Good agreement between model and experimental curves is found. Because of its analytical nature, the proposed model can be implemented in circuit simulators. © 2005 American Institute of Physics.Publicationtype: Journal Article25 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Impact of soft and hard breakdown on analog and digital circuits(2004-12-01); The influence of gate oxide breakdown of one MOS transistor on the functionality of simple analog and digital circuits is studied. The main changes in the transistor behavior such as the additional gate current as well as transconductance and threshold voltage degradation are pointed out and their respective impact on circuit characteristics is analyzed. With this approach, it is possible to identify critical transistors during the design stage and implement appropriate countermeasures. Depending on the application, some circuits may be functional even after breakdown of one of their transistors.Publicationtype: Journal Article11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Consistent model for the voltage and temperature dependence of the soft breakdown conduction mechanism in ultrathin gate oxides(Elsevier, 2004-04-01); ; ; The voltage and temperature dependence of the soft breakdown conduction mechanism in ultrathin gate oxides in MOS structures was investigated. Measurements performed on p- and n-type substrate samples with different oxide thicknesses were compared, and the results analyzed within the framework of the quantum point contact model for dielectric breakdown. The model has been extended so as to include the thermal vibrations of the atoms that form the constriction's bottleneck. A new interpretation of the model parameters, in connection with the potential drops distribution, is discussed.Publicationtype: Journal Article6 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Charakterisierung von MOS-Transistoren vor und nach GateoxiddurchbruchThe continuous scaling of integrated circuits in the last decades has led to gate oxide thicknesses below 2nm in MOS transistors of state of the art technologies. Breakdown of such thin oxides becomes intrinsically more likely, and the 1 billion transistor chip is already within reach. Therefore, the probability of having at least one oxide breakdown within the projected circuit lifetime of 10 years seems quite high. In this work, the characteristics of MOS transistors before and after gate oxide breakdown are studied. Different categories of breakdown are identified and models for the dc characteristics as well as the noise (random telegraph signals) after breakdown are developed. The models are implemented to analyze the effect of breakdown on different analog and digital circuits. It is shown that, according to the application and breakdown type, circuits may be functional after breakdown of a transistor. With the presented approach it is possible to point out critical transistors in the circuit and analyze the impact of breakdown during the design stage.Publicationtype: Doctoral Thesis794 340 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Simple estimation of the effect of hot-carrier degradation on scaled nMOSFETs(Taylor & Francis, 2003-10-01); ; The influence of parasitic charge at the Si-SiO2 interface on the characteristics of n-channel metal oxide semiconductor field effect transistors (nMOSFETs) scaled down to a feature size of 25 nm is studied. The results are that the impact of parasitic charge on threshold voltage and drain current degradation significantly decreases. Additionally, as the hot-electron injection current densities are lowered for scaled-down nMOS transistors, less charge build-up occurs. This opens the perspective to make use of alternative gate dielectrics even if they have a higher interface trap density. These materials offer the advantage of greater dielectric constants than silicon oxide, so that a physically thicker dielectric will limit the gate tunnelling current.Publicationtype: Journal Article5 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modeling random telegraph signals in the gate current of metal-oxide-semiconductor field effect transistors after oxide breakdown(American Institute of Physics (AIP), 2003-07-01); ; The study presents the measurement data of random telegraph signals (RTS) in the gate current of n-channel metal-oxide-semiconductor field effect transistors (MOSFETs) after oxide breakdown. Two types of behavior were observed of the time constants and the relative amplitudes of the signals as a function of gate voltage. A theory is developed relating time constants and relative amplitudes of the fluctuations to the energetic and geometric trap location in the oxide.Publicationtype: Journal Article17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Experimental study and modeling of the temperature dependence of soft breakdown conduction in ultrathin gate oxidesIn this work, we focus our interest on the temperature dependence of soft breakdown conduction (SBD), mainly in the range in which real devices are commonly operated (-20°C<T<160°C). A thorough experimental study involving samples with different oxide thicknesses and substrate types is presented, and the results are interpreted in terms of an extended version of the quantum point contact model (QPC) for the non-zero temperature case. Even though several approaches attempting to explain the SBD I-V characteristics have been proposed, analytical modeling of its temperature dependence has always been restricted to a single bias condition. In contrast, we provide a simple parameterization of the experimental data which accounts for both I-V and I-T characteristics within a consistent framework based on the physics of mesoscopic conductors. The magnitude of the current flowing through the SBD spot essentially depends on the barrier height encountered by incoming electrons, while the shape of the I-V characteristics is dictated by the particular features of the spot and the potential drop distribution.Publicationtype: Conference Paper12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Charge-based capacitance measurements (CBCM) on MOS devicesA new simple method of measuring capacitance-voltage characteristics of MOS devices is presented. Proceeding from the charge-based capacitance measurement technique suggested recently, a compact test structure with high resolution has been developed, which only requires measurement of dc quantities. The method was tested on a 0.6-μm CMOS process with small and large area capacitors and compared to well-known high-frequency capacitance-voltage results. Beside using a reference structure, a second means of extracting parasitic effects is demonstrated for small structures. The test structure allows measurements in a wide frequency range with high accuracy and low noise contribution at small capacitance levels.Publicationtype: Journal Article47 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Temperature dependence of the hard breakdown current of MOS capacitors(Bolognia University, 2002); ; ; I-V curves as a function of temperature of broken down n- and p-type MOS capacitors with different oxide thicknesses are presented. In accumulation, a crossover of the temperature dependent curves is observed. At low voltages the hard breakdown current increases with temperature whereas it decreases with temperature for higher voltages. This behaviour can be straightforwardly linked to the available charge for conduction at the electrodes. MINIMOS simulations as well as theoretical considerations were performed that clearly support this idea.Publicationtype: Conference Paper12