Properties of Si-SiO2 structure with ultrathin dielectrics for nano- and microelectronics device application

Studies of the growth kinetics and optical properties of thermally grown ultrathin SiO₂ have been performed. The thermal oxidation kinetics of Si at the initial stage of oxide growth was investigated in the temperature range of 700-950°C at atmospheric pressure in dry oxygen flow. A peculiarity in the kinetic curves d(t) is observed in the thickness range of 5-7 nm. It is connected with features of thermal growth and structural transformation of SiO₂ films in the case of strong compressive stress. The influence of wet (RCA) and dry (hydrogen plasma) cleaning procedures on the optical properties of SiO₂ films was studied by spectroscopic ellipsometry and infrared spectroscopy. From the analysis of the pseudodielectric function of Si in the presence of oxide, the oxidation-induced stress was evaluated. Its level depends on the plasma treatment temperature and is of the order of 10⁹ dyn/cm², but it is smaller than that in oxides on standard RCA cleaned Si. Analysis of the IR spectra has shown that the structure of SiO₂ layers grown on hydrogenated silicon possesses a relatively larger contribution of 6-fold SiO₄ rings indicating a more ordered and less stressed SiO₂ lattice.