The influence of ionic activity on the electrical properties of pecvd (teos) silicon dioxide

摘要

A Plasma enhanced CVD system was modified to place a potential screen between a plasma and a silicon wafer. Silicon dioxide from an organometallic precursor (TEOS) was deposited onto silicon wafers. In this way, any alteration of the screen potential resulted in a modified ion speed, or the removal of the ion flux incident on the wafer. The oxides films produced in this manner were analyzed by Raman spectroscopy, and both C-V and I-V techniques. The characterization results suggest an important role for Oxygen ion bombardment on the TEOS oxidation process, such as the removal of carbon compounds from the film as TEOS oxidizes. We have evidence that ion bombardment decreases the dielectric constant and increases the hysteresis of the SiO_x films. A qualitative model to explain the experimental results was developed.