Piotr Spiewak

Ab Initio Analysis of Point Defects in Plane-Stressed Si or Ge Crystals

The effect of compressive or tensile plane-stress on formation energies and electronic properties of point defects in Si single crystal was studied by first principles approach for in-plane strain up to 5.0 %. It was found that the formation energy of interstitial Si (I) decreased under tensile in-plane strain. On the other hand, the formation energy of vacancy (V) decreased under compressive in-plane strain. The most stable states of I and V in intrinsic Si were I +2 at T site and V 0 respectively, independent of type and value of the in-plane strain.

Simulation of Vacancy Cluster Formation and Binding Energies in Single Crystal Germanium

Results are presented of the simulation of the properties of vacancy clusters in single crystal germanium. Classical molecular dynamics calculations based on a Stillinger and Weber potential were used in a theoretical investigation of different growth patterns of vacancy clusters Vi. The formation and binding energies of vacancy clusters have been studied in the range 1 i 35. The energetically favourable growth mode and an estimate of the effective surface energy was determined for a vacancy clusters containing up to 35 vacancies

A Comparison of Intrinsic Point Defect Properties in Si and Ge

Intrinsic point defects determine to a large extent the semiconductor crystal quality both mechanically and electrically not only during crystal growth or when tuning polished wafer properties by thermal treatments, but also and not the least during device processing. Point defects play e.g. a crucial role in dopant diffusion and activation, in gettering processes and in extended lattice defect formation. Available experimental data and results of numerical calculation of the formation energy and diffusivity of the intrinsic point defects in Si and Ge are compared and discussed. Intrinsic point defect clustering is illustrated by defect formation during Czochralski crystal growth.

Ab-initio simulation of formation and diffusion energies of intrinsic point defects in Ge

The application of germanium in complementary metal-oxide semiconductors (CMOS) technology has attracted considerable attention recently (1). Its high carrier mobility and low-voltage operation, enabled by the narrower band gap together with development of high-k dielectrics as insulating layer, makes Ge a possible alternative to Si and Si