Comparison of Phosphosilicate Glass Films Deposited by Three Different Chemical Vapor Deposition Methods

Abstract

Properties of phosphosilicate glass (PSG) films deposited by the plasma chemical vapor deposition (CVD), low‐pressure CVD, and atmospheric CVD methods are compared. Stress behavior of plasma PSG films is almost the same as that of low‐pressure PSG films. The stress values change from compressive to tensile with increasing phosphorus concentration. On the other hand, the stress of atmospheric PSG films is tensile, and decreases monotonously with increasing phosphorus concentration. One of the causes is thought to be that the densities of plasma PSG films and low‐pressure PSG films are larger than that of atmospheric PSG films. Infrared absorption (IR) at P=O bonds is greatest in the atmospheric PSG films, lower in plasma PSG films, and lowest in low‐pressure PSG films. This phenomenon is attributable to the quantity of oxygen gas present at reaction time. The surface morphologies of the plasma PSG and low‐pressure PSG after etching are rough, but the surface morphology of the atmospheric PSG is very smooth. Also, it was found that the change in infrared spectra after temperature‐humidity treatment is smallest for the atmospheric PSG films. But the crack in the atmospheric PSG films is generated more easily than for the plasma PSG films or low‐pressure PSG films.