We use Fowler–Nordheim tunneling current oscillations to accurately determine the thicknesses of ultrathin SiO2 films, and with the thicknesses as input, we employ precision single wavelength ellipsometry to determine the real part of the refractive index for thin SiO2 films in the range of 4–6 nm. An average value for this refractive index was found to be 1.894±0.110. This value is shown to yield SiO2 thicknesses to an accuracy of ±0.1 nm. A SiO2 thickness-refractive index interpolation formula for the thin film regime is given.

No abstract

No abstract

This paper reports a titanium salicide process capable of fabricating low resistance salicide (<5 ohms/sq.) on narrow polysilicon leads (line widths less than 0.35 μm) which are heavily doped with arsenic and boron. The process utilizes conventional processing but avoids excessive vertical scaling of the titanium silicide film. The process has been demonstrated on a 0.35 μm CMOS technology and results show that a process window exists which is suitable for technologies of 0.35 μm and below. The most serious scaling issue for titanium salicide appears to be the silicide film thickness.

Dilute HF/RCA and IEMC/SC2 cleans have been evaluated on two process lines with different metallic contamination levels. VPD-DSE-TXRF and SPV techniques were used to monitor the metallic contamination. Gate oxide integrity(GOI) tests were performed on several structures. Both HF/RCA and IMEC/SC2 cleans have shown good Qbd and Ebd results for the clean process line. Lower Qbd and Ebd values were obtained for both cleans in the relatively contaminated process line. These results suggest that poor GOI is related to the metallic contamination in the oxide or at the SiO2/Si interface.