A new degradation mode for advanced heterojunction bipolar transistors under reverse bias stress

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Enthalpy based modeling of pulsed excimer laser annealing for process simulation

We present an enthalpy-based model for pulsed excimer laser annealing of crystalline silicon in the melting regime that integrates into the technology computer-aided design (TCAD) suite Sentaurus Process of Synopsys. The currently one-dimensional model includes laser absorption, a transient simulation of the heat flux, melting of the surface layer, and undercooling during recrystallization. To verify the model, its predictions for a laser pulse with a duration of 150 ns and a wavelength of 308 nm were compared to those of a phase-field implementation of melting laser annealing by La Magna et al. The two models show a good agreement for the melt depth, melt duration, and melt front dynamics. In a second step, model predictions were compared to melt depths extracted from SIMS measurements of ion implanted and excimer-laser-annealed silicon samples. They were found to agree within the experimental error. Variation of the beam parameters indicated a strong influence of lase r energy density fluctuations on the melt depth

Transfer of physically-based models from process to device simulations: Application to advanced SOI MOSFETs

International audienceDopant implantation, followed by spike annealing is one of the main focus areas in the simulation of silicon processing due to its ability to form highly-activated ultra-shallow junctions. Coupled with the growing interest in the use of silicon-on-insulator (SOI) wafers, modelling and simulation of the influence of SOI structure on damage evolution and ultra-shallow junction formation on one hand, and on electrical MOSFET device characteristics on the other hand, are required. In this work, physically-based models of dopant implantation and diffusion, including amorphization, defect interactions and evolution, as well as dopant-defect interactions in both bulk silicon and SOI are integrated within a unique simulation tool to model the different physical mechanisms involved in the process of ultra-shallow junction formation. The application to 65 nm SOI MOSFET devices demonstrated the strong impact of the process simulation models on the simulated electrical device characteristics, in particular for both defect evolution and defect dopant interaction with the additional silicon/buried oxide (Si/BOX) interface. Simulation results of the threshold voltage (V th) and the variation of the on-and off-state currents of the explored structures are in good agreement with experimental data and can provide important insight for optimizing the process in both bulk silicon and SOI technologies

Evaluation and modeling of lanthanum diffusion in TiN/La2O3/HfSiON/SiO2/Si high-k stacks

International audienceThermally induced interface chemistry in Mo/B4C/Si/B4C multilayered films J. Appl. Phys. 112, 054317 (2012) Probing the buried C60/Au(111) interface with atoms J. Chem. Phys. 136, 214706 (2012) Enhancement of perpendicular magnetic anisotropy through reduction of Co-Pt interdiffusion in (Co/Pt) multilayers Appl. Phys. Lett. 100, 142410 (2012) Organic salts as super-high rate capability materials for lithium-ion batteries Appl. Phys. Lett. 100, 091905 (2012) Additional information on Appl. Phys. Lett

Effect of Germanium content and strain on the formation of extended defects in ion implanted Silicon/Germanium

International audienceWe studied the evolution of extended defects in relaxed and strained Si and SiGe structures after an amorphising implant. The investigated structures included three relaxed SiGe alloy layers with various Ge contents (20, 35 and 50 at.%), a 40 nm-thick tensely strained Si layer and a 40 nm-thick compressively strained Si0.8Ge0.2 layer. Concerning the compositional effects, we found that the increase of Ge concentration in relaxed SiGe structures leads to: (i) an overall decrease of the defect stability and to (ii) an enhanced {311}-to-loops transformation. As for the strain effects, it is found that: (i) Tensile strain (in Si) retards the transformation of {311} defects into loops; (ii) compressive strain (in SiGe) enhances the transformation of {311}s into loops; (iii) in all cases, the overall defect stability is not strongly modified in the presence of strain. The observed results are discussed in terms of the various mechanisms involved, including the increase of the interstitial diffusivity in relaxed SiGe alloys (with respect to Si) and the strain effects on both interstitial equilibrium concentration and defect formation energy

Modeling of the effect of the buried Si–SiO2 interface on transient enhanced boron diffusion in silicon on insulator

International audienceThe effect of the buried Si-SiO 2 interface on the transient enhanced diffusion TED of boron in silicon on insulator SOI structures has been investigated. To this purpose, boron marker layers were grown by chemical vapor deposition on Si and SOI substrates and implanted under nonamorphizing conditions with 40 keV Si + ions. The experimental results clearly confirm that the Si-SiO 2 interface is an efficient trap for the Si interstitial atoms diffusing out of the defect region. Based on these experiments, existing models for the simulation of B TED in silicon have been modified to include an additional buried recombination site for silicon interstitials. The simulation results provide an upper limit of 5 nm for the recombination length of interstitials at the Si-SiO 2 interface

Evaluation and modeling of lanthanum diffusion in TiN/La <inf>2</inf>O <inf>3</inf>/HfSiON/SiO <inf>2</inf>/Si high-k stacks

In this study, TiN/La 2O 3/HfSiON/SiO 2/Si gate stacks with thick high-k (HK) and thick pedestal oxide were used. Samples were annealed at different temperatures and times in order to characterize in detail the interaction mechanisms between La and the gate stack layers. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements performed on these samples show a time diffusion saturation of La in the high-k insulator, indicating an La front immobilization due to LaSiO formation at the high-k/interfacial layer. Based on the SIMS data, a technology computer aided design (TCAD) diffusion model including La time diffusion saturation effect was developed. © 2012 American Institute of Physics

Modeling boron dose loss in sidewall spacer stacks of complementary metal oxide semiconductor transistors

International audienceThe presence of capping materials during annealing (activation for example) can substantially impact the silicon junction profiles of Complementary Metal Oxide Semiconductor Field Effect Transistors (CMOSFET), depending on the nature of these layers. In this paper we specifically investigated the boron out-diffusion from a silicon junction into the silicon oxide in presence of a silicon oxide/silicon nitride capping bi-layer similar to the stacks used to form sidewall spacers. After 120 s anneal we observed with secondary ion mass spectrometry (SIMS) substantial boron dose loss in silicon and segregation at the silicon oxide interface related to oxide and nitride material properties, in particular to the hydrogen concentration. We then modeled the boron profiles in both silicon and oxide as a function of the hydrogen static and dynamic in the materials. The exponential-like boron diffusion profiles observed in oxide are reproduced by introducing a long hop mechanism mediated with hydrogen-related defects (HRDs). (C) 2016 Elsevier Ltd. All rights reserved