Growth and doping of SiC-thin films on low-stress, amorphous Si₃N₄/Si substrates for robust microelectromechanical systems applications

Abstract

The N₂-doped 3C-SiC thin films have been grown by low-pressure, chemical vapor deposition (LPCVD) on amorphous Si₃N₄/p-Si (111) substrates using the single, organosilane-precursor trimethylsilane [(CH₃)₃SiH]. The effects of N₂ flow rate and growth temperature on the electrical properties of SiC films were investigated by Hall-effect measurements. The electron-carrier concentration is between 10¹⁷–10¹⁸/cm³. The lowest resistivities at 400 K and 300 K are 1.12×10⁻² and 1.18×10⁻¹ cm, respectively. The corresponding sheet resistances are 75.02 Ω/□ and 790.36 Ω/□. The SiC film structure was studied by x-ray diffraction. The 3C-SiC films oriented in the 〈111〉 direction with a 2ϑ peak at 35.5° and line widths between 0.18–0.25° were obtained. The SiC/Si₃N₄ interface is very smooth and free of voids. The fabrication of microelectromechanical (MEMS) structures incorporating the SiC films is discussed.