[11a-PB2-1~10] 13.3 Insulator technology

[11a-PB2-1] Cause of generating the penetration barrier of H₂O molecule into SiO₂ and Si₃N₄ films

〇Tomoki Oku¹, Masahiro Totsuka¹, Hajime Sasaki¹ (1.Mitsubishi Electric)

Keywords:humidity resistance, molecular orbital calculation method, silicon oxide

To evaluate the moisture resistance of SiO_x films, the penetration barrier of the H₂O molecules into the SiO₂ crystal (cristobalite, tridymite, quartz, coesite) and the Si₃N₄ crystal, and the size of the interstitial voids were calculated by a semi-empirical molecular orbital method. As a result, we found as follows;
(1) the moisture resistance of the SiO₂ crystal (coesite) is not larger than that of the Si₃N₄ crystal but is the highest among the SiO₂ crystals,
(2) the difference in the moisture resistance of the SiO₂ crystal with various crystal structures is explained by the void sizes,
(3) the difference in the moisture resistance between SiO₂ crystal and Si₃N₄ crystal cannot be explained by only the void size alone.