Correlation between mechanical and electrical properties of silicon oxide deposited by PECVD-TEOS at low temperature

In this work, we present the physical characterization of PECVD-TEOS silicon oxide thin films obtained through a new deposition procedure with two steps of oxygen plasma during the process. It was observed that there was an increase in the silicon oxide density together with an increase in the mechanical stress in the film. These results were correlated with the electrical properties of MOS capacitors. The silicon oxide films deposited at lower rates presented lower leakage currents over a wider range of applied fields before breakdown. Higher breakdown strengths could be associated with higher dielectric constants, associated with a higher amount of adsorbed water. This effect could be assigned to the post-deposition water incorporation into the silicon oxide film. Films were obtained using a deposition procedure that starts with pure oxygen plasma. It was observed that this procedure, which avoids the exposition of interface to uncracked TEOS, leads to MOS capacitors with lower leakage currents and higher breakdown strengths.