Nanocomposites and nanomaterials

Magnetoconductance of Polycrystalline Silicon in SemOI-structures 
A.Druzhinin1, I.Ostrovskii1, Yu.Khoverko1, K. Rogacki2 
1 Department of Semiconductor Electronics, Institute of Telecommunications, Radioelectronics and Electronic Engineering, Lviv Polytechnic National University, Kotliarevskyi Str., 1, Lviv-79013, Ukraine.
E-mail: druzh@polynet.lviv.ua
2 Institute of Low Temperature and Structure Research PAN, Wroclaw, Poland.

The experimental results of researches of polycrystalline silicon films in SemOI- structures under the influence of magnetic fields up to 14 T at cryogenic temperatures to the temperature of liquefied helium are presented. The concentration of charge carriers in the poly-Si samples according to studies of the Hall coefficient corresponded to values in the range from 7×1017 to 1.7×1020 сm-3, which covers the metal-dielectric transition for silicon (5×1018 сm-3) from the dielectric to the metal side of the transition. The structure and morphology of polycrystalline resistors in samples of SemOI-structures varied from fine-crystalline (about 30 nm) to large-crystalline (about 300 m) depending on the modes of the laser recrystallization process for homogenization of the material [1]. The samples were subjected to deformation (level of deformation =-3.8×10-3 rel. units) to determine the effect of material dispersion on low-temperature conductivity. Uniaxial compression deformation was carried out by using the difference in the coefficients of thermal expansion of the copper substrate and the attached SemOI-structure. The results of magnetoresistance studies of both deformed and non-deformed samples of SemOI-structures are presented. To describe the nature of the magnetoconductance of low-alloy polysilicon samples with a semiconductor conductivity, we used a model according to which the positive magnetoconductance is explained by the deformation of the wave functions of localized holes due to the magnetic field [2]. 

1.	Druzhinin A., Ostrovskii I., Kogut I., Khoverko Yu., Koretskii R., Kogut Iu. Magneto-transport properties of polysilicon in SOI structures at low temperatures // Materials Science in Semiconductor Processing. – 2015. –31. – P. 19–26
2.	Shklovskii A.I., Efros A. L. Electron Properties of Doped Semiconductors. “Nauka” Publishing House, Moscow 1979; 416. (in Russian).