Computer analysis of an influence of oxygen vacancies on the electronic properties of the SnO ₂ surface and near-surface region

An influence of the surface stoichiometric defects on the electronic and electrical properties of SnO ₂ layers has been studied by means of computer simulation. The surface potential and in-depth potential profiles in the accumulation region have been rigorously computed at various temperatures (from 400 to 900 K). The behaviour of both the surface and bulk Fermi level position versus temperature has been analysed. Furthermore, in-depth profiles of carrier concentration and the surface potential as well as the SnO ₂ layer conductance for different surface donor density of state have been calculated. It has been found that the surface reduction and bulk donor concentration (in the range from 3 × 10 ¹⁴ to 3 × 10 ¹⁸ cm ^-3) are strongly correlated with the development of near-surface accumulation region and thus modification of the layer electrical parameters.