Depth-resolved correlation between physical and electrical properties of stressed SiN_x gate insulator films

摘要

The physical and electrical properties of SiN_x gate insulator films with compressive and tensile internal stress have been investigated using various characterization techniques. The mechanical hardness measured by nano-indenter system showed the different distribution in the film depth direction according to the type of film stress. The uniformity of optical property inside films had a correspondence to the mechanical properties of stressed SiN_x films, as well. The contents and bonding states of hydrogen influenced the mechanical and optical properties of stressed SiN_x films. The leakage characteristics of tensile SiN_x films with uniform physical properties exhibited the lower current density than the compressive films with ~10−7 A/cm2 until 8 MV/cm. The correlation between physical and electrical properties depending on the internal stress will suggest the appropriate optimization of SiN_x gate insulator films to enhance the device performance and reliability.