Optimization of residual stress of SiO2/organic silicon stacked layer prepared using inductively coupled plasma deposition

Abstract

Silicon dioxide (SiO2) has great potential to be used for thin-film encapsulation for flexible electronic devices, but it easily peels off with a large thickness to fail encapsulation. In this study, organic silicon films with high transmittance and tensile stress are prepared and inserted into SiO2 and polyethylene terephthalate substrate to reduce residual stress. Radiofrequency inductively coupled plasma chemical vapor deposition (ICPCVD) with a gas mixture of argon and trimethylsilane is used for organic silicon film deposition, and the power is varied to investigate its effect on film properties. The plasma emission spectra show that the power of 900W leads to a balance between the increase in precursor radical intensities and reduction in ion bombardment at increasing power. The resultant film has the highest refractive index value, the largest ratio of SiCSi to SiCHx terminate bonds and the smoothest surface morphology. The residual stress of SiO2 can be tremendously reduced from −360 to −31.6MPa with organic silicon layer beneath. Furthermore, the eight-pair SiO2/organic silicon stacked encapsulation barrier demonstrates a transmittance of 85.4%, water-vapor transmission rate of 8.3×10−10g/cm2/day, and a residual stress of −102MPa.