Properties of Silicon Dioxide Films Prepared Using Silane and Oxygen Feeds by PE-CVD at Low Power Plasma

In this paper we report on synthesis of thin films of silicon dioxide (SiO2) using conventional plasma enhanced chemical vapor deposition (PE-CVD) from pure silane (SiH4) and oxygen (O2), gas mixture at low RF power (30 Watt) and at moderate substrate temperature (250 °C). We have systematically investigated the material properties of these films as a function of oxygen partial pressure in view of their use in MOS devices. The formation of SiO2 thin films is confirmed by Fourier transform infrared (FTIR) spectroscopy. The thickness and refractive indices of the films measured by ellipsometry. C-V measurement shows that the electrical properties are directly related to process parameters and Si/SiO2 interface. The MOS structures were also fabricated from optimized SiO2 layer to study C-V measurement and to estimate interface, oxide and effective border traps density.