Charge carrier transport in silicon heterojunctions with a thin titanium oxide layer

The work performed studies of Al–Ti–Si and Al–Ti–TiO_x–Si structures with an n-TiO_x/p–Si heterojunction. The TiO_x layer was formed using the atomic layer deposition method; its thickness was 5 nm. To study the layers and composition of the structures, methods of electron microscopy, Auger spectroscopy, and Raman scattering were used. Much attention is paid to the study of electrical characteristics. It was found that the Al–Ti–Si structure is a Schottky diode, there is no minority carrier current in it, and the current–voltage characteristics are described by classical models. In the Al–Ti–TiO_x–Si heterostructure, titanium oxide has n-type conductivity and is an injector of electrons into p-Si, which leads to the appearance of recombination currents in the space charge region, which lies entirely in silicon. When reverse biased, the titanium oxide layer acts as a conductor of electrons and contributes to the development of tunnel generation currents.