Importance of heat-up ramp rate for palladium-silicide fully-silicided-gate structure formation
Silicidation process for fully-silicided (FUSI) Pd2Si gate formation has been investigated. Two types of heating equipment was used for siliciding palladium deposited on a poly-Si/SiO2/Si MOS structure. One is lamp heating in a sputtering chamber and another is hot-plate heating. The former provide slower heat-up ramp because of relatively large thermal capacity. In this case, metal-rich phase was formed in the first stage of silicidation and it changed to Pd2 Si phase by additional heating after completion of silicidation reaction. FUSI utilizes impurity pre-doping to poly-Si to modulate workfunction. Pre-doping to poly-Si sometimes resulted in needle structure formation on a top of silicided film and voids at the interface between silicide and SiO2. These defects were reduced by silicidation with hot plate heating. In addition, Pd2 Si phase was obtained at the early stage of silicidation. Palladium and silicon reacts even at temperatures lower than 250degC. Therefore, in the case of the lamp heating, silicidation during heating is not negligible. These results are explainable considering change of major diffusion species during silicidation
Transmission electron microscopy and X-ray diffraction investigation of phase formation and transition between Pd2Si and PdSi in Pd thin films on (111)Si
Abstract Phase formation and transition between Pd 2 Si and PdSi in Pd thin films on (111)Si has been investigated by X-ray diffraction and transmission electron microscopy. In as-deposited and 200 °C/1 h annealed Pd(30nm)/(lll)Si samples, epitaxial Pd 2 Si was found to coexist with the unreacted Pd layer. In samples annealed at 250–800 °C, epitaxial Pd 2 Si is the only suicide phase present. PdSi was found to form along with Pd 2 Si in samples annealed at 850 °C. Pd 2 Si was found to be the predominant phase along with PdSi in samples annealed at 900–1000 °C. Pd 2 Si and PdSi were found to be the stable phases at 300–800 and 850–875 °C, respectively. The phase transition between Pd 2 Si and PdSi is reversible. In samples annealed at 900 °C, epitaxial Pd 2 Si is initially the only suicide phase present; then polycrystalline PdSi becomes the dominant phase. After annealing for more than 240 s, polycrystalline Pd 2 Si predominates over PdSi. The peculiar Pd 2 Si to PdSi, then back to Pd 2 Si phase transition behavior is correlated with the formation of PdSi islands, which is thought to alter the order of the total energy of the system.
Air scrubbing techniques for ammonia and odor reduction at livestock operations : review of on-farm research in the Netherlands
Acid scrubbers and biotrickling filters have been developed for ammonia (NH3) removal at pig and poultry houses 
in The Netherlands over the last 20 years to prevent acidification and eutrophication of soils. Because of growing 
suburbanization, odor removal is increasingly considered important as well. In this review, we report the results of the on-farm 
research on full-scale operated scrubbers for treatment of exhaust air from animal houses with regard to NH3 and odor 
removal in The Netherlands. The NH3 removal of acid scrubbers ranged from 40% to 100% with an overall average of 96%. 
The NH3 removal of biotrickling filters ranged from -8% to +100% with an overall average of 70%. Minimum empty bed air 
residence times (EBRTs) were 0.4 to 1.1 s. For acid scrubbers, process control with pH measurement and automatic water 
discharge is sufficient to guarantee sufficient NH3 removal. For biotrickling filters, however, improvement of process control 
is necessary to guarantee sufficient NH3 removal. The odor removal of acid scrubbers ranged from 3% to 51% with an overall 
average of 27%. The odor removal of biotrickling filters ranged from -29% to +87% with an overall average of 51%. 
Minimum EBRTs were 0.5 to 2.3 s. Further research is necessary to explain this variation and to improve the odor removal 
efficiency of both acid scrubbers and biotrickling filters.