Simulation Of Boron Diffusion Research Articles

Characterization of dual phase boride coatings on Sverker 3 steel and simulation of boron diffusion

AbstractThe Sverker 3 steel was treated by solid boriding in the range 1173–1273 K for holding times ranged from 1 to 7 h. The processes resulted in two-phase (FeB + Fe2B) boride layers except the treatment at 1173 K for 1 h where the Fe2B was formed only. The growth of borides obeys a typical parabolic law, with the maximum thickness of 120 ± 4.5 µm. Considerable redistribution of carbon and alloying elements took place during boronizing; carbon and silicon were pushed out from borides while chromium and tungsten were rather gathered in these compounds. The microhardness of Fe2B ranged between 1600 and 1700 HV 0.1, and that of FeB reached 2100–2200 HV 0.1. The average diffusion coefficient (ADC) approach was applied by assuming the linearity of boron concentration profiles across the iron boride layers. This approach allowed us to obtain the boron diffusivities in both the FeB and Fe2B. Afterwards, the boron activation energies in both layers were obtained by fitting the temperature evolution of calculated boron diffusivities in the two iron boride phases with the Arrhenius relations. The assessed boron activation energies in FeB and Fe2B were, respectively, 215.18 and 203.6 kJ mol−1. Finally, a comparison of these values of energies was made with literature results.

Simulation of boron diffusion during low-temperature annealing of implanted silicon

Modeling of ion-implanted boron redistribution in silicon crystals during low-temperature annealing with a small thermal budget has been carried out. It was shown that formation of “tails” in the low-concentration region of impurity profiles occurs due to the long-range migration of boron interstitials.

Atomistic Simulation of Boron Diffusion with Charged Defects and Diffusivity in Strained Si/SiGe

We discuss the boron diffusion in a biaxial tensile strained {001} Si and SiGe layer with kinetic Monte Carlo (KMC) method. We created a strain in silicon by adding a germanium mole fraction in silicon in order to perform a theoretical analysis. The generation of a strain in silicon influences in the diffusivity as well as the penetration profile during the implantation. The strain energy for the charged defects has been calculated from the ab-initio calculation while the diffusivity of boron was extracted from the Arrhenius formula. Hereby, the influence of the germanium content on the dopant diffusivity was estimated. Our KMC study revealed that the diffusion of the B atoms was retarded with increasing Germanium mole fraction in a strained silicon layer. Furthermore, we derived a functional dependence of the in-plane strain as well as the out-of-plane strain on the germanium mole fraction, which lies in the distribution of equivalent stresses along the Si/SiGe interface.

Atomistic Simulation of Boron Diffusion with Charged Defects and Diffusivity in Strained Si/SiGe

We discuss the boron diffusion in a biaxial tensile strained {001} Si and SiGe layer with kinetic Monte Carlo (KMC) method. We created a strain in silicon by adding a germanium mole fraction in silicon in order to perform a theoretical analysis. The generation of a strain in silicon influences in the diffusivity as well as the penetration profile during the implantation. The strain energy for the charged defects has been calculated from the ab-initio calculation while the diffusivity of boron was extracted from the Arrhenius formula. Hereby, the influence of the germanium content on the dopant diffusivity was estimated. Our KMC study revealed that the diffusion of the B atoms was retarded with increasing Germanium mole fraction in a strained silicon layer. Furthermore, we derived a functional dependence of the in-plane strain as well as the out-of-plane strain on the germanium mole fraction, which lies in the distribution of equivalent stresses along the Si/SiGe interface.

Simulation of boron diffusion in Si and strained SiGe layers

Boron outdiffusion from the base into the emitter and collector caused by annealing in SiGe heterobipolar transistors (HBTs) has a serious influence on the transit frequency. One solution of the problem of boron outdiffusion is the creation of intrinsic spacers between the base, emitter and collector layers to prevent diffusion of boron across the heterointerface. For optimisation of SiGe HBT properties, several simulators are used. This paper presents a quantitative analysis of a SiGe HBT by process simulators SUPREM IV.GS and ISE TCAD-DIOS. Models for simulation of a boron-doped SiGe base of HBT are discussed and compared.

Measurement and simulation of boron diffusion in strained Si 1− xGe x epitaxial layers with a linearly graded germanium profile

The diffusion of boron in compressively strained Si 1− x Ge x epitaxial layers with graded Ge profiles grown by rapid pressure chemical vapor deposition during furnace and rapid thermal annealing has been studied. Comparison of the Si 1− x Ge x samples to Si samples after furnace annealing (FA) and rapid thermal annealing (RTA) revealed a retarded B diffusion inside the strained Si 1− x Ge x layer. FA after RTA has only a marginal effect on B diffusion. The extracted B diffusivity from the present studies is very well comparable with available experimental and simulation results. A simple empirical expression for B diffusion is presented and incorporated into a diffusion model for dopants in heterostructures. Good agreement between the measured and simulated diffusivity is observed. It is argued that B diffusion in strained Si 1− x Ge x layers requires the inclusion of both trapping effect and strain in the formulation of the diffusion mechanism.

Monte Carlo simulation of Boron diffusion during low energy implantation and high temperature annealing

ABSTRACTWe use a kinetic Monte Carlo model to simulate the implantation of low energy Boron in Silicon, from 0.5 to 1 keV, at high doses, 1015 ions/cm2. The damage produced by each ion is calculated using UT-Marlowe, based on a binary collision approximation. During implantation at room temperature,, silicon self-interstitials, vacancies and boron interstitials are allowed to migrate and interact. The diffusion kinetics of these defects and dopants has been obtained by ab initio calculations as well as Stillinger Weber molecular dynamics. Clustering of both self-interstitials, vacancies and boron atoms is included. We also model the diffusion of the implanted dopants after a high temperature annealing in order to understand the transient enhanced diffusion (TED) phenomenon. We observe two different stages of TED During the first stage vacancies are present in the lattice together with interstitials and the diffusion enhancement is small. The second stage starts after all the vacancies disappear and gives rise to most of the final TED.