A method of obtaining quantitative two-dimensional (2D) maps of strain by the convergent beam electron diffraction technique in a transmission electron microscope is described. It is based on the automatic acquisition of a series of diffraction patterns generated from digital rastering the electron spot in a matrix of points within a selected area of the sample. These patterns are stored in a database and the corresponding strain tensor at each point is calculated, thus yielding a 2D strain map. An example of application of this method to cross-sectioned cells fabricated for the 0.15 μm technology of flash memories is reported.

The diffusion of indium in silicon has been investigated in the temperature range of 800 to 1000 °C by using secondary ion mass spectroscopy and transmission electron microscopy. Our data indicate that, for implants at 150 keV through a thin oxide layer (19 nm), the amount of dopant that leaves the silicon is only controlled by the flow of indium that reaches the surface, being both the segregation coefficient at the interface SiO2/Si and the indium diffusion coefficient in the oxide favorable to the out-diffusion. Comparison between experimental and simulated profiles has evidenced that, besides the expected transient enhanced diffusion occurring in the early phases of the annealing, a heavy loss of dopant by out-diffusion was associated with a high In diffusivity near the surface. Measurements of the hole concentration in uniformly doped silicon on insulator samples performed in the temperature range of 700 to 1100 °C indicate that indium solubility is equal or greater than 1.8×1018 cm−3; this value is higher than those previously proposed in literature.

In this paper, the correlation between dislocation density and transistor leakage current is demonstrated. The stress evolution and the generation of defects are studied as a function of the process step, and experimental evidence is given of the role of structure geometry in determining the stress level and hence defect formation. Finally, the role of high-dose implantations and the related silicon amorphization and recrystallization is investigated.

In this paper we report on a general methodology to investigate nanowire MOSFETs based on the coupling of mechanical simulation with 3-D real-space Monte Carlo simulation. The Monte Carlo transport model accounts for both strain silicon and quantum mechanical effects. Mechanical strain effects are accounted for through an appropriate change of the anisotropic band structure computed with the empirical pseudopotential method. Quantum effects are instead included by means of a quantum mechanical correction of the potential coming from the self-consistent solution of the Schrödinger equation. This methodology has been then applied to the simulation of a test case silicon nanowire n-MOSFET. Impact of mechanical strain and quantum effects on the drive current is investigated. It is shown that only the inclusion of strain and quantum mechanical effects allows a good agreement with experimental data, demonstrating the validity of the proposed methodology for ultimate devices.Index Terms-Monte Carlo simulation, nanowire MOSFET, quantum effects, strained silicon.

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