Formation of High-Quality SiO2 and SiO2/Si Interface by Thermal-Plasma-Jet-Induced Millisecond Annealing and Postmetallization Annealing

Abstract

For the formation of a high-quality SiO2 and SiO2/Si interface, we have applied thermal-plasma-jet (TPJ)-induced millisecond annealing to SiO2 films deposited at 300 °C by plasma-enhanced chemical vapor deposition (PECVD). By TPJ annealing at 1088 K for 2.8 ms, the amount of Si–OH bond groups decreased significantly and an increase in the amount of Si–O–Si bond groups was observed. This result suggests that the desorption of H2O and the cross linkage of Si–O–Si are promoted, and the densification of SiO2 films is achieved. By performing TPJ annealing followed by postmetallization annealing (PMA), a high-quality SiO2/Si interface with a trap density (Dit) of 3.0×1010 cm-2 eV-1 was achieved. In addition, TPJ-annealed SiO2 films show a higher durability under a constant current stress than SiO2 films prepared only by PMA. This is attributed to the improvement of the bulk chemical bond network of SiO2 films by TPJ annealing. These results indicate that the combination of TPJ and PMA is one of the promising low-temperature processes for the long-term reliability of SiO2 films and the formation of a high-quality SiO2 and SiO2/Si interface.