Interface Trap Density Metrology of state-of-the-art undoped Si n-FinFETs

The presence of interface states at the MOS interface is a well-known cause of device degradation. This is particularly true for ultra-scaled FinFET geometries where the presence of a few traps can strongly influence device behavior. Typical methods for interface trap density (Dit) measurements are not performed on ultimate devices, but on custom designed structures. We present the first set of methods that allow direct estimation of Dit in state-of-the-art FinFETs, addressing a critical industry need.Comment: 9 pages, 4 figures, *G.C.T. and A.P. contributed equally to this wor

Thermionic Emission as a tool to study transport in undoped nFinFETs

Thermally activated sub-threshold transport has been investigated in undoped triple gate MOSFETs. The evolution of the barrier height and of the active cross-section area of the channel as a function of gate voltage has been determined. The results of our experiments and of the Tight Binding simulations we have developed are both in good agreement with previous analytical calculations, confirming the validity of thermionic approach to investigate transport in FETs. This method provides an important tool for the improvement of devices characteristics.Comment: 3 pages, 3 figure, 1 tabl

Interface trap density metrology from sub-threshold transport in highly scaled undoped Si n-FinFETs

Channel conductance measurements can be used as a tool to study thermally activated electron transport in the sub-threshold region of state-of-art FinFETs. Together with theoretical Tight-Binding (TB) calculations, this technique can be used to understand the evolution of source-to-channel barrier height (Eb) and of active channel area (S) with gate bias (Vgs). The quantitative difference between experimental and theoretical values that we observe can be attributed to the interface traps present in these FinFETs. Therefore, based on the difference between measured and calculated values of (i) S and (ii) |dEb/dVgs| (channel to gate coupling), two new methods of interface trap density (Dit) metrology are outlined. These two methods are shown to be very consistent and reliable, thereby opening new ways of analyzing in situ state-of-the-art multi-gate FETs down to the few nm width limit. Furthermore, theoretical investigation of the spatial current density reveal volume inversion in thinner FinFETs near the threshold voltage.Comment: 12 figures, 13 pages, Submitted to Journal of Applied Physic

P-I 2 Fundamental relation between local and effective transversefielddependent mobility for electrons in inversion channels

Abstract This paper describes a new modeling approach that relates the local mobility to the experimentally determined macroscopic or effective mobility as a function of the vertical electric field. Using the technique of integral representations [ 11 it is possible to find a mathematical condition which any local mobility model has to fulfill to be in accordance with experiment. A local mobility model used in a 2D device simulator has to meet this requirement in order to achieve quantitative agreement between experimental and simulated data. f l Numerical modeling of transport in semiconductor devices is playing an increasingly important role in their development. The mobility is a key quantity for the purpose of modeling. While the low-and high field behavior of the mobility in bulk Si is relatively well understood The microscopic details are not available. Very useful models for the local mobility have been proposed by parameterizing the model by an effective field Eeff. However, they are in most cases using for the local model the one of the external average mobilty peff. In 2D device simulators the current at each node in the MOS inversion layer is calculated using the local transverse field Eeff parameters for a chosen mobility model. It was noted in Because the peff is defined for Long channels, one can use a linear model for the potential v. Secondly, a transformation from the independent variable 'x' to the vertical field is possible through the relation 10

Modelled decomposition mechanism of flame retarded poly(vinyl acetate) by melamine isocyanurate

Model polymer poly(vinyl acetate) (PVAc) was combined with melamine isocyanurate (MIC) as intumescent flame retardant composite. This work emphasises on the study of the decomposition mechanism and compared with a single fire test in order to show its performance as flame retarded composite. As such, mass loss cone calorimetry tests were performed and compared with it inert and oxidative decompositions in lab tests. PVAc/MIC composites cannot be ignited with high loadings MIC. Difference curves in oxidative conditions revealed that the composites with MIC show only positive differences, indicating a high stabilisation, especially in the temperature region of a mild flame (500–700 °C). Experiments performed with TG coupled with mass spectroscopy and analyses on partially degraded residues with solid-state 13C-NMR enabled the construction of the complete decomposition mechanism. MIC has both a heat-sink FR activity as well as a crosslinking role in the stabilization of the polymer. The latter then creates a highly stabilised char at elevated temperatures in oxidative environments. The formed char starts to degrade only 100 °C higher than the pure polymer within a heating. The degradation of formed char of pure PVAc is autocatalytic; this behaviour disappears upon addition of sufficient amount of MIC. Therefore, the transport of fuel towards the gaseous phase is limited, creating an efficient flame retardant system.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Flame retardancy and degradation mechanism of poly(vinyl acetate) in combination with intumescent flame retardants: I. Ammonium poly(phosphate)

The present paper deals with the flame retardancy study of model compound Poly(vinyl acetate) (PVAc) blended with ammonium poly(phosphate) (APP) as flame retardant. APP shows good activity within PVAc in fire tests at low mixing ratios in terms of reduction of rate of heat release (RHR). Creating difference thermograms by means of thermogravimetric analysis (TGA) learned that the classic deacetylation step of the polymer is accelerated by the presence of APP in the composite, followed by stabilisation of the formed char. A systematic model to investigate chemical decomposition reactions of blends of polymers with flame retardants is introduced to build a complete mechanistic reaction model. To perform this, both evolved gas and solid state analysis of intermediate products are coupled. For the combination of PVAc and APP, APP breaks into monophosphate during the deacetylation step of PVAc and fully cross-links with the polymer by P-O-C cross-link bonds. The formed cross-linked material further aromatises in an oxidative environment and is highly stabilised as was shown using difference thermograms: blends of PVAc and APP appear to be more than 20% stable at 600 °C in comparison with the decomposition of the pure materials. At elevated temperatures, the phosphate structure degrades, leading to the full evaporation of the carbonaceous residue within the char.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Transport-based Dopant Metrology in Advanced FinFETs

Ultra-scaled FinFET transistors bear unique fingerprint-like device-to-device differences attributed to random single impurities. Through correlation of experimental data with multimillion atom simulations in NEMO 3-D, we can identify the impurity’s chemical species and determine their concentration, local electric field and depth below the Si/SiO2 interface. The ability to model the excited states rather than just the ground states is the critical need. We therefore demonstrate a new approach to atomistic impurity metrology and confirm the assumption of tunneling through individual impurity quantum states

Method of forming a Yb-doped Ni full silicidation low work function gate electrode for n-MOSFET

US7504329Granted Paten

Low work function metal alloy

EP1722404A3Published Applicatio

Low work function metal alloy

EP1796151A1Published Applicatio