Positron probing of phosphorus-vacancy complexes in silicon irradiated with 15 MeV protons

[摘要] Defects in phosphorus-doped silicon samples of floating-zone material, n-FZ-Si(P), produced under irradiation with 15 MeV protons at room temperature are studied by positron annihilation lifetime spectroscopy over the temperature range of ∼ 30 K-300 K and by low-temperature Hall effect measurements. After annealing of E-centersand divacancies, we detected for the first time high concentrations of positron traps which had not been observed earlier. These defects are isochronally annealed over the temperature interval of ∼ 320 °C-700 °C; they manifest themselves as electrically neutral deep donor centersin the material of n-type. A long-lived component of the positron lifetime, τ2(I2≤ 60%) ∼ 280 ps, attributed to these centers, suggests a relaxed configuration involving two vacancies. The enthalpy and entropy of annealing of these centers are Ea∼ 1.05(0.21) eV and ΔSm≈ 3.1(0.6)kB, respectively. It is argued that the microstructure of the defect consists of two vacancies, VV, and one atom of phosphorus, P. The split configuration of the VPV complex is shortly discussed.

[发布机构] Martin Luther University Halle, Department of Physics, Halle; 06120, Germany^1;Ioffe Physico-Technical Institute, St. Petersburg; 194021, Russia^2;Minia Univrsity, Faculty of Science, Physics Department, Minia; 61519, Egypt^3;Inst. Ion-Plasma and Laser Technol., Inst. of Electronics, Tashkent; 700187, Uzbekistan^4;St. Petersburg State Polytechnic University, St. Petersburg; 195251, Russia^5

[效力级别] 化学

[关键词] Hall effect measurement;Low temperatures;Phosphorus-doped;Positron annihilation lifetime spectroscopy;Positron lifetime;Temperature intervals;Temperature range;Vacancy complexes