Physico-Chemical nanomaterials science

X-stimulated evolution of point defects and their complexes in silicon structures
D.P. Slobodzyan, M.O. Kushlyk, R.M. Lys, B.V. Pavlyk
Department of Sensor and Semiconductor Electronics, Ivan Franko National University of Lviv, 79017, 107 Hen. Tarnavskoho Str., Lviv, Ukraine. 
Е-mail: slobodzyand@gmail.com

The development of modern nanoelectronics in the direction of significant reduction of elements poses increased requirements for the state of the surface layer of silicon structures. The presence of spot and line defects can significantly affect the surface activity. This can be reflected in the efficiency and durability of these elements due to weak electromagnetic fields, in particular.
P-type Cz-Si with ρ = 24 ohm•cm resistivity was used for the studies. Samples have been cut from a dislocation-free (Nd ≤ 102 cm-2), single crystal silicon disk with flat surfaces orientation (111). 
The aim of the work was to form a surface-barrier structure (SBS) Bi-Si-Al and to investigate the change in their electro physical characteristics under the influence of X-radiation.
Irradiation of samples was carried out with X-ray tube (V = 45 kV, I = 8 mA, W-anode).
Electrophysical properties of SBS were studied by measuring and analysing current-voltage characteristic (IVC) and high-frequency capacitance-voltage characteristic (CVC) curves. From experimental C-V characteristics, the distribution of surface-state density in silicon’s bandgap on the boundary of Si-SiO2 was calculated.
Changes of the defect structure of silicon p-type crystal surface layer under the influence X-radiation were investigated by the methods of deep levels capacitance-modulation spectroscopy (DLCMS)
The analysis of electrophysical properties irradiated SBS confirmed the existence of two competing radiation processes: the radiation-stimulated ordering of the defect structure of the near-surface layer (D < 390 Gy) and the generation of defects (D > 390 Gy).
Analysis of the DLCMS spectra showed evolution of oxygen and carbon centers and formation of complexes CI-OI by Watkins mechanism in surface layer of silicon.