Formation Mechanisms of the Deformed Oxide Layer in a Tungsten Polycide Structure

Abstract

The gyrosynchrotron spectra are computed in a nonuniform magnetic field case, taking into account the self-and gyroresonance absorption. It is found that the peak frequency ν p of the gyrosynchrotron spectrum systematically increases with the increasing photosphere magnetic field strength B 0 and increasing viewing angle θ. It is also found for the first time that there are good positive linear correlations between ν p and B 0 , and between log ν p and log θ, with linear correlation coefficient 0.99 between ν p and B 0 and 0.95 between log ν p and log θ. We apply the correlations to analyze two burst events observed with OVSA and find that the evolution tendencies of the photosphere magnetic field strength B 0 estimated from the above expression are comparable with the observational results of SOHO/MDI. We also give a comparison of the diagnostic results of coronal magnetic field strength in both uniform and nonuniform source models.

Oxidation behavior of a patterned TiSi2/polysilicon stack

“…In the WSi 2 /polysilicon gate stack, the high-temperature oxidation was also known to be effective in suppressing the metal oxidation. 6,7 As shown in Fig. 5, this study found that only the pure silicon-oxide was formed on the surface of unpatterned TiSi 2 film at all temperatures examined, which is in agreement with the previous articles [2][3][4][5] and indicates that 750°C is high enough to supply a sufficient amount of silicon.…”

“…In the case of practical use of the silicide films as the gate material, however, the oxidation behavior of patterned polycide may be different from that of an unpatterned one. In fact, Mashiko et al 6 and Kim et al 7 reported an abnormal oxidation of WSi 2 sidewall in the patterned WSi 2 /polysilicon gate stack. They showed that the abnormal oxidation results in the oxidation of metal as well as silicon and suggested that high temperature oxidation or nitrogen implantation in the silicide suppress the abnormal oxidation.…”

Sidewall oxidation behavior of dichlorosilane-based W-polycide gate

“…The abnormally grown oxide was reported to be a metal-oxide including silicon-oxide at low oxidation temperature ͑ϳ600°C͒, whereas it was a porous silicon-oxide that was due to formation of volatile metaloxide and its subsequent vaporization at higher oxidation temperature ͑ϳ750°C͒. 8,9 The abnormal oxidation was also reported to be suppressed when amorphous WSi x was formed. 9 Phosphorus or nitrogen implantation can be used to obtain the amorphous phase of WSi x .…”

Oxidation Behavior of Nitrogen Implanted Dichlorosilane‐Based W‐polycide Gate

“…Recently a number of researchers reported that tungsten silicide abnormally oxidized to form laterally overgrown oxide layer on its sidewall, which can cause serious problems in device fabrication processes such as lightly doped drain (LDD) ion implantation. [11][12][13] The abnormally grown oxide was reported to be a metal oxide including silicon oxide at low oxidation temperature (ϳ600ЊC), whereas it was a porous silicon oxide due to formation of volatile metal oxide and its subsequent vaporization at higher oxidation temperature (ϳ750ЊC). 11,12 Depending on the processes used, the thickness of laterally overgrown oxide is in the range of 100ϳ200 Å per side.…”

“…[11][12][13] The abnormally grown oxide was reported to be a metal oxide including silicon oxide at low oxidation temperature (ϳ600ЊC), whereas it was a porous silicon oxide due to formation of volatile metal oxide and its subsequent vaporization at higher oxidation temperature (ϳ750ЊC). 11,12 Depending on the processes used, the thickness of laterally overgrown oxide is in the range of 100ϳ200 Å per side. This amount of deformation is not so significant for wide gate lines; however, its impact would be more and more significant for narrow gate lines, especially, for subquarter micron lines.…”