Nanoporous Low-k Allyltrimethylsilane (ATMS) Films Deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD)

Abstract

ATMS(allyltrimethylsilane: CH2=CHCH2Si(CH3)3 was selected as a precursor for SiCOH/CxHy dual phase films and it is expected that allyl group and three methyl groups attached on silicon could be unitized effectively on a molecular scale to make SiCOH(thermally stable phase) films along with CxHy(labile phase) imbedded in it. Direct plasma reactor was used where radical oxygen was generated in the chamber and ATMS was introduced into the mainstream of the plasma. The refractive index and film thickness were measured and calibrated with an ellipsometer and a field emission scanning electron microscopy (FE-SEM). Chemical bonding and compositions of films were investigated using FT-IR spectra and X-ray photoemission spectroscopy(XPS), respectively. The dielectric constant was obtained by capacitance-voltage(C-V) measurement of the metal-insulator-semiconductor(MIS) structure having a mercury electrode at 1MHz.