In this work, we present a model describing the boron redistribution during laser thermal annealing in the melting regime based on the adsorption of boron atoms at the solid-liquid interface. To validate the model, we performed SIMS measurements on silicon samples implanted with boron with an energy of 3 keV and doses of 3x10(13) cm(-2) and 4x10(14) cm(-2) annealed with a XeCl excimer laser with a wavelength of 308 nm, a pulse duration of 160 ns, and up to 10 consecutive pulses. After calibration, our model is able to reproduce the measured profiles for the different process conditions. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

In this work we present transient reflectivity measurements, maximum melt depths, and surface topographies of ion implanted silicon samples after pulsed excimer laser thermal annealing in the melting regime. The samples were annealed with different laser energies and number of pulses. We found that the melt dynamics change after the first laser pulse resulting in a shorter melt time but deeper melt depth. This can be explained by a change in reflectivity due to boron activation, surface modifications and small changes in the oxide thickness.

TiN/HfSiON/SiO2/Substrate stacks were investigated with C-V measurements and SIMS.No linear relationship of the threshold voltage on the La concentration at the HfSiON/SiO2 was found.A linear relationship of the threshold voltage on the La sheet concentration in the HfSiON was found.Crystallization of the HfSiON is proposed as explanation of the experimental findings. We investigated the dependence of the electrical properties of TiN/La2O3/HfSiON/SiO2/Si-substrate stacks with 15nm thick HfSiON layers on annealing temperature and time. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and capacitance-voltage (C-V) measurements were used to characterize the La depth profiles and the electrical properties. We found that the threshold voltage (Vth) shift after annealing correlates linearly with the total amount of La diffused into the HfSiON rather than with the La concentration at the HfSiON/SiO2 interface. This unexpected behavior can be explained by the decreased thermal stability of thick (2nm) HfSiON layers which probably leads to phase separation during annealing and therefore to HfO2/SiO2 interfaces all over the stack.

Anomalous impurity redistribution after a laser irradiation process in group-IV elements has been reported in numerous papers. In this Letter, we correlate this still unexplained behavior with the peculiar bonding character of the liquid state of group-IV semiconductors. Analyzing the B-Si system in a wide range of experimental conditions we demonstrate that this phenomenon derives from the non-Fickian diffusion transport of B in l-Si. The proposed diffusion model relies on the balance between two impurity states in different bonding configurations: one migrating at higher diffusivity than the other. This microscopic mechanism explains the anomalous B segregation, whereas accurate comparisons between experimental chemical profiles and simulation results validate the model.

BF3 plasma immersion ion implantation (PIII) is a promising technique in the race for highly boron doped P+/N ultra-shallow junctions (USJs) in complementary metal oxide semiconductor (CMOS) silicon technologies. Implantation conditions used in BF3 PIII lead to high super-saturations (>= 1 x 10(20) cm(-3)) of both boron and silicon interstitial atoms in the implantation region. In such conditions, very large loop-shaped boron-interstitial clusters (BICs) are formed during subsequent thermal anneals, as confirmed by transmission electron microscopy (TEM) measurements.In this study, amorphizing BF3 PIII implants (10 keV, 5 x 10(15) cm(-2)) followed by different thermal anneals were carried out in order to investigate the large BICs precipitation. A "large BICs" model based on moments approach allowed to reproduce the experimental data including boron diffusion profiles (obtained by SIMS) and boron electrical activation obtained by Hall effect sheet resistance measurements. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

In the race for highly doped ultra-shallow junctions (USJs) in complementary metal oxide semi-conductor (CMOS) technologies, plasma immersion ion implantation (PIII) is a promising alternative to traditional beamline implantation. Currently, no commercial technology computer aided design (TCAD) process simulator allows modeling the complete USJ fabrication process by PIII, including as-implanted dopant profiles, damage formation, dopant diffusion and activation. In this work, a full simulation of a p-type BF3 PIII USJ has been carried out. In order to investigate the various physical phenomena mentioned above, process conditions included a high energy/high dose case (10 kV, 5x10(15) cm(-2)), specifically designed to increase damage formation, as well as more technology relevant implant conditions (0.5 kV) for comparison. All implanted samples were annealed at different temperatures and times. As implanted profiles for both boron and fluorine in BF3 implants were modeled and compared to Secondary Ion Mass Spectrometry (SIMS) measurements. Amorphous/crystalline (a/c) interface depths were measured by transmission electron microscopy (TEM) and successfully simulated. Diffused profiles simulations agreed with SIMS data at low thermal budgets. A boron peak behind the a/c interface was observed in all annealed SIMS profiles for the 10 kV case, indicating boron trapping from EOR defects in this region even after high thermal budgets. TEM measurements on the annealed samples showed an end of range (EOR) defects survival behind the a/c interface, including large dislocation loops (DLs) lying on (001) plane parallel to the surface. In the last part of this work, activation simulations were compared to Hall measurements and confirmed the need to develop a (001) large BICs model.

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 similar to 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 laser energy density fluctuations on the melt depth. (C) 2012 Elsevier B. V. All rights reserved.

In this work, we investigated four possible mechanisms which were candidates to explain the shape of boron profiles after ion implantation and melting excimer laser annealing in silicon. A laser with a wavelength of 308 nm and a pulse duration of ∼180 ns was used. To simulate this process, an existing model for the temperature and phase evolution was complemented with equations for the migration of dopants. Outdiffusion, thermodiffusion, segregation, and adsorption were investigated as possible mechanisms. As a result, we found that outdiffusion and segregation can be excluded as major mechanisms. Thermodiffusion as well as adsorption could both reproduce the build-up at low melt depths, but only adsorption the one at deeper melt depths. In both cases, ion beam mixing during SIMS measurement had to be taken into account to reproduce the measured profiles.