Surface Alteration of Amorphous Si₃N₄ Films by ArF Excimer Laser Irradiation

Abstract

We report on the electron spin resonance (ESR) study of the photo-oxidative stress-mediated protein conformation changes in the spin-labelled protein staphylococcal nuclease (SNase). The photo-oxidative stress was brought on by photosensitization of singlet oxygen ( 1 g ) in the presence of a novel photosensitizer, water-soluble fullerol C 60 (OH) 19 (ONa) 17 , and resulted in partial protein denaturation. This process was monitored via ESR measurements performed for a spin-labelled SNase Thr-62-Cys mutant, with MTSSL spin label (SL) attached to the cysteine 62 residue (SNase T62C-SL). Prior to ESR measurements of the oxidative stress-induced alterations in protein conformations, the efficiency of C 60 (OH) 19 (ONa) 17 for 1 g -generation was confirmed by three different techniques: (i) selective reactive scavenging of 0953-8984/07/285201+13$30.00

Atomic‐Order Thermal Nitridation of Silicon at Low Temperatures

“…It is found that experimental data are very closely located on a single curve. When the NH3 surface reaction proceeds according to a first-order reaction including an initial small and very fast reaction, the N atom concentration is given by (Nsat -Njflexp(-k203t)} + 1V [6] where N4 is the N atom concentration in saturation, N1 is the N atom concentration at the initial nitridation within a minute of NH3 exposure, and k2 is the nitridation rate constant. The solid line in Fig.…”

“…It has been reported that thermal nitridation of SiO, using NH3 proceeds via the replacement of oxygen by nitrogen atoms under the action of hydrogen.' When the NH3 surface reaction proceeds according to a first-order reaction including an initial small and very fast reaction, the N atom concentration is given by (Nsat -Njflexp(-k203t)} + 1V [6] where N4 is the N atom concentration in saturation, N1 is the N atom concentration at the initial nitridation within a minute of NH3 exposure, and k2 is the nitridation rate constant. Therefore, it is expected that oxygen did not play a significant role in the present experiments on the nitridation of Si.…”

“…Paniez et al,6 Vinet et al,7 Paniez and Pain,8 and Pain et al6 suggested that the soft baking temperature should be between the glass transition temperature of the bulk material and the onset of thermal deprotection so that the lithographic properties of a chemically amplified photoresist can be preserved. Beauchemin et al3 used various experimental techniques to study the influence of the residual solvent of a photoresist film after spin coating on its dissolution and thermal behaviors.…”

“…Schlegel et al4'5 found that the condition of soft baking has a significant effect on the mobility of the photoacid generator in deep UV lithography. Paniez et al,6 Vinet et al,7 Paniez and Pain,8 and Pain et al6 suggested that the soft baking temperature should be between the glass transition temperature of the bulk material and the onset of thermal deprotection so that the lithographic properties of a chemically amplified photoresist can be preserved.…”

Ultra thin silicon nitride prepared by direct nitridation using ammonia decomposed species

“…For these reasons, formation of SiN at low temperature is strongly required. A lot of groups have proposed to form SiN at low temperatures by electron beam induced nitridation [6], excimer -laser enhanced nitridation [7,8] and plasma enhanced CVD [9,10]. However, these excitation methods may induce damage in the formed nitride film and/or surface of substrates.…”