Synthesis of Hydrogenated Silicon Oxycarbonitride from a Gas Mixture of Methyltris(Diethylamino)Silane, Nitrogen, and Oxygen

Abstract

A synthesis of thin films consisting of hydrogenated silicon oxycarbonitride using high-frequency discharge plasma from a novel organosilicon compound methyltris(diethylamino)silane (MTDEAS) mixed with oxygen and nitrogen are studied. CVD diagrams are obtained as a result of the thermodynamic modeling of the Si–C–N–H–O system in the temperature range from 300 to 1300 K, which makes it possible to optimize the synthesis of film materials such as SiC_xN_yO_z:H. The silicon oxycarbonitride films of various compositions are experimentally obtained in the range of deposition temperatures from 373 to 973 K for different compositions of the initial MTDEAS + O₂+ xN₂ gas mixture. A change in the chemical composition of the gas mixtures leads to obtaining SiC_xN_yO_z:H films having a large range of functional properties; the refractive index varies from 1.5 to 2.21; the adjustable transparency varies from 92–99.7% in the UV visible and IR spectral regions; and the tunable band gap characteristics vary in the range from 2.5 to 4.5 eV and from 2.9 to 0.7 eV for films grown from MTDEAS + O₂+ N₂ and MTDEAS + O₂+ 2N₂ mixtures, respectively. It is shown that the films contain nanocrystals of phases belonging to structures such as Si_{3 – x}C_xN₄ embedded in the amorphous matrix of hydrogenated silicon oxycarbonitride layers.