Magnetic susceptibility of n- and p-Si single crystals containing thermodonors

Using a series of experimental methods (Hall effect, electron paramagnetic resonance and magnetic susceptibility (MS, χ)) comparison has been made for the kinetics of formation inherent to different types of thermodonors (TDs) (doubly-charged and shallow ones) under thermal treatments (TT) at 450 °C with the kinetics of paramagnetic center accumulation in the samples obtained by the MS method. The absence of correlation between these dependences has been shown. The dependences χ(H) obtained both at 300 and 77 K that have orientation and paramagnetic component determine neither of these two kinds of TD-centers as it was in the case of 450 °C TT for p-Si(B) samples where the χ par component is determined by the concentration of deep TDs (Еі ≥ 0.2 еV). The χ(H) value in the n-Si(P) samples after TT at 450 °C is determined, evidently, by intermediate non-stable complexes, as well as by those formed during rapid cooling the sample

Mass-spectrometric investigations of gas evolution

Method of mass-spectrometry with time-of-flight recording of the desorbed products was used to study the gas evolution of impurities from the subsurface layer of Si crystals molten by the electron beam (of ~2 mm² area) in the vacuum of 10⁻⁵ – 10⁻⁷ Pa. It is shown that irrespective of vacuum level, oxygen (m = 32) and hydrogen (m = 2) in the molecular state as well as Si atoms (m = 28) are registered as the main components of gas evolution in the mass-spectrum in melting. With longer time of the subsurface layer exposure in the molten state, an indication of CO evolution (fragment peak m = 12) appears in the mass-spectrum. There is, however, a ground to believe that this is the consequence of gas evolution from the fixtures, and not from the Si sample. Features of gas evolution were revealed at the initial stage of heating and melting of Si sample, depending on the previous heat-treatment of the sample. If melting the subsurface zone proceeds after contact with the atmosphere, initial peaks of evolution of oxygen and hydrogen molecules and Si atoms are observed. These are partially weakened with further keeping the sample in the molten state. In our opinion, such a peak is due to contamination of the surface at such a contact. A long-term exposure in vacuum of a sample cooled after melting does not lead to appearance of the above peak at subsequent melting

Development of the physical insight into the nature of the factors that control electrophysical and other properties of semiconductors

Evolution of the physical insight into the nature of main factors that influence the energy band structure formation in semiconductors, and, hence, their basic electrophysical, optical, thermoelectrical and even mechanical properties, is reviewed. These factors are: - dopant and residual impurities, intrinsic point defects, elongated defects (of the dislocation type), - electrically active thermal donors and other complexes that are formed due to direct impurity-impurity or impurity-defect interaction. Keywords: electron transport, point defect complex, impurity-impurity interaction, impurity-defect interaction

The features of magnetoresistance of n-Si doped with phosphorus from the melt and by nuclear transmutation

The magnetic field dependencies Dr^/r0 = f(H) were investigated for phosphorus-doped n-Si crystals at a temperature of 77.4 K in classical strong magnetic fields up to 200 kOe. We revealed and discuss some distinctions in the field dependencies of magnetoresistance for crystals doped from melt and those doped by nuclear transmutation. It is shown that mag-netoresistance ∆ρ⊥/ρ₀ in classical strong magnetic fields is due to the statistically distributed Herring-type defects in the crystals studied