[16a-P4-1~8] 13.3 Insulator technology

[16a-P4-4] Surface oxidation process of silicon nitride films under humid environment

〇Tomoki Oku¹, Toshihiko Shiga¹, Masahiro Totsuka¹, Shinichi Takagi¹ (1.Mitsubishi Electric)

Keywords:silicon nitride, humidity resistance, molecular orbital calculation

Silicon nitride films with high density defects are oxidized under a humid environment. A molecular orbital calculation was applied to clarify the surface oxidation reaction of the silicon nitride films. The surface atomic bonds of silicon nitride films are not easily broken by the first attack of a pair of H₃O⁺ and OH^- ion because the most of the reaction is not exothermic. However, the most of the second attack leads to the exothermic reaction and proceeds to the breakage of the atomic bonds on the surfaces. After the second attack, the creation of a SiH(OH)(=OH)₂ molecule and the desorption of a NH₃ molecule are found on the silicon nitride surfaces.