IMPROVED PROCESS FOR LIQUID-PHASE DEPOSITION OF SILICON DIOXIDE

An improved process for liquid phase deposition of silicon dioxide (SiO2) at 50-degrees-C is successfully developed, Contrary to conventional processes, silicic acid (SiO2:xH2O) is used instead of SiO2 powder to saturate hydrofluorosilicic acid at 30-degrees-C. This will shorten the period required for solution preparation to 3 h. Water is now taking the role of boric acid (or Al) to reduce the concentration of HF in the solution and leads to deposition of oxide. The corresponding growth rate of SiO2 is about 50 nm per hour, larger than that reported in literature with boric acid concentration of 0.010 M. When this oxide is used to fabricate the metal-oxide-semiconductor (MOS) capacitor, the flatband voltage turns out to be 0.277 V and the achieved oxide breakdown field strength is 9 MV/cm.