Development and optimisation of a SiO2 PVD technique based on the thermal decomposition of PDMS

This work reports the development of a novel and facile physical vapour deposition (PVD) system for SiO2 deposition with a wide and controllable range of final film thicknesses. An investigation of the steady-state deposition temperature, heating rate, and PDMS source mass dependence of the deposited SiO2 layer thickness was performed using a variety of experimental techniques. SiO2 layers were characterised by scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), x-ray photoelectron spectroscopy (XPS), grazing incidence attenuating total reflection Fourier transform infrared spectroscopy (GATR-FTIR), contact profilometry (CP), and white light profilometry (WLP). It was found that the thickness of the SiO2 layer was linearly proportional to the PDMS source mass for large source masses with a nonlinear (parabolic) relationship for smaller source masses, but a non-monotonic relationship was observed between thickness and source material heating rate. The steady-state deposition temperature above the decomposition threshold did not directly affect layer thickness within the range investigated but, the lower the temperature, the greater the film uniformity.

Automated summary

This study presents a new and convenient physical vapour deposition (PVD) system for SiO2 deposition, allowing a wide range of controllable final film thicknesses. Experimental techniques were used to investigate the effects of steady-state deposition temperature, heating rate, and PDMS source mass on the thickness of the deposited SiO2 layer. The SiO2 layers were characterized using various techniques such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), x-ray photoelectron spectroscopy (XPS), grazing incidence attenuating total reflection Fourier transform infrared spectroscopy (GATR-FTIR), contact profilometry (CP), and white light profilometry (WLP). The results showed that the SiO2 layer thickness was linearly proportional to the PDMS source mass for large source masses, but exhibited a nonlinear (parabolic) relationship for smaller source masses. The thickness of the SiO2 layer also showed a non-monotonic relationship with the source material heating rate, and the steady-state deposition temperature had no direct effect on layer thickness within the investigated range, but influenced film uniformity.