On the Nature of Radiation Resistance in Compensated Silicon

Russian Physics Journal -     

Comparative analysis of (p,d), (d,t) and (3He, α) reactions on13C nucleus

The angular distributions of the (p, d), (d, t) and(³He, ) reactions on¹³C have been analysed within the framework of DWBA in which additional information on nuclear vertex constants was introduced. Although all these reactions seem to be similar single nucleon transfer, their mechanism is shown to be quite different and so is the information extracted thereof. While from the (p, d) reactions spectroscopic factors may be extracted unambiguously, from the (d, t) reactions it is possible to obtain directly the values of vertex constants only, which in turn are consistent with those determined by extrapolation of the experimental cross sections of the (p, d) reactions to the pole.In the case of (³He, ) reactions, however, the analysis indicates inadequacy of the DWBA concerning the calculations of central partial amplitudes. For a more reliable extraction of structural information, besides the correct normalization of peripheral amplitudes, a contribution of more complex mechanisms must be taken into account.     

Spectroscopic factors of9Be,10B and13C from (d,t) reactions

The differential cross sections of tritons from the (d, t) reaction on⁹Be,¹⁰B and¹³C targets have been measured in the angular range of 5° _LAB110° with relatively small errors, 5%. The experimental data were analysed in terms of the standard DWBA using both zero-range and exact finite-range approaches.     

Relaxation kinetics of photoconductivity in <Emphasis Type="Italic">р</Emphasis>-silicon compensated by phosphorus atoms

The relaxation kinetics of photoconductivity in neutron-doped silicon (NDS) of the p-type is discussed. It is found that the relaxation process in the compensated p-Si<B, P> differs from that in the reference p-Si<B> sample. The difference is explained on the basis of concept of different micrononuniformity of the material conductivity. A method based on studying the dependences of charge-carrier mobility on annealing time is developed for determining thermal annealing of structural defects.     

Influence of the Post-Diffusion Hardening Rate and Thermal Treatment on the Thermal Stability of the Charge-Carrier Lifetime in Overcompensated n-Si

The influence of the rate of hardening changing in the range 0.6–250 deg/min and of repeated thermal treatment at temperatures of up to 1020 K on the charge-carrier lifetime in overcompensated n-Si is investigated. It is demonstrated that the value of in n-Si can be controlled by adjusting the cooling rate at a constant diffusion temperature. The observed effects are discussed based on the concepts of different degrees of microinhomogeneity of the electrical conductivity in n-Si, which depends on the post-diffusion cooling rate.     

Method for determining the depleted zone thickness in silicon charged particle detectors

A method for determining the thickness of silicon charge particle detectors has been developed. The method is based on measurements of spectra from a standard ¹³⁷Cs γ source, whose shape changes with detector thickness. The method can be used in the thickness range ～50–6000 μm with an accuracy from 20 to 10%, respectively. No complex equipment or laborious calculations are needed.     

On the thermostability of electrical properties of <Emphasis Type="Italic">p</Emphasis>-Si<P,Ni> and <Emphasis Type="Italic">p</Emphasis>-Si<P,Cu>

Silicon samples with various nickel and copper concentrations were studied by the method of isochronal annealing. In so doing, the temperature of total decomposition of Ni and Cu centers was found to depend on the concentration of nickel and copper atoms in silicon overcompensated from the n-to the p-type. The decomposition temperatures of Ni and Cu centers increase with decreasing the distance between the impurity atoms. This effect is explained by the peculiarities in the distribution of the compensating-impurity atoms within the fluctuation regions being formed in silicon during doping. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 73–75, December, 2005.     

Nature of the effect of an increase in the charge-carrier lifetime for irradiatedn-Si<P, Rh>

An increase and stabilization of the charge-carrier lifetime in compensated n-Si<P, Rh> exposed to radiation is discussed. A mechanism is suggested which explains this effect based on concepts of the increase of potential fluctuation barriers upon exposure to radiation. Tashkent State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 3–6, July, 2000.     

Comparison of asymptotic normalization coefficients for 10B → 9B + n and 10B → 9Be + p configurations obtained from 10B(d,t)9B and 10B(d,3He)9Be reactions

The differential cross sections of the ¹⁰B(d,t)⁹B and ¹⁰B(d,³He)⁹Be reactions at E _d = 25 MeV were measured to obtain the ratio of asymptotic normalization coefficients for the bound states of the last neutron and the last proton in the symmetric nucleus ¹⁰B. The obtained ratio is shown to be in agreement with the theoretical value.     

Investigation of Si<B, S≥and Si<B, Rh≥compensated photoresistors

The influence of the electric parameters of compensating sulfur and rhodium impurities on the photosensitivity of p-type silicon is discussed in the present paper. Conditions of the increased photosensitivity ofSi<B, S> andSi<B, Rh> in the near-IR region of the spectrum are defined. The increase of the photosensitivity of compensated silicon at 300 K is found to be due to a higher degree of microinhomogeneity in the resistivity (with a simultaneous increase in the degree of compensation) irrespective of the electric parameters of the compensating impurity in silicon. Tashkent State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 77–80, June, 2000.