VLSI를 위한 플라즈마 열적 질산화막의 형성

Plasma Enhanced Thermal Nitridation of $SiO_2$ for VLSI

Nitridation of about 300\ulcornerSiO2 filmss thermally grown on Si was performed in NH3 plasm ambient (0.2-2 torr) at 900\ulcornerC-1100\ulcorner for 15-20 minutes. The peoperties of those films have been investigated by analyzing the AES and the SIMS data, and the results of the I-V and the C-V measurements. At the plasma ambient of less than 1.5 torr pressure, etching of the films have been shown. Above the 1.5 torr pressure, however, SiO2 films were nitrided as SiIxNy. Plasma thermal nitridation of SiO2 by addition of small amount (6%) of CF4 to the NH3 showed higher pile-up N concentration in the surface region of SiOxNy film. The higher the nitridation temperature is and the longer the nitridation time is the larger the dielectric constant is. The plasma thermal nitridation of silicon dioxide on silicon causes the flat-band voltage shift based on the formation of the positive charge. The conduction mechanism for SiOxNy films could be elucidated by Fowler-Nordheim tnneling model. By SIMS analysis, surface of the film nitrided in plasma process has less contamination than that of the film nitrided in open-tube process.