Ta and Ta-N films sputtered with pure Ar, 10%, 20%, 30%, 40%, 50%, and 60% N 2 /Ar gas ratios were found to be a mixture of ␤-Ta and bcc-Ta, bcc-Ta, bcc-TaN x , expanded bcc-TaN x , hcp-Ta 2 N, fcc-TaN, and fcc-TaN ͑nearly amorphous͒ phases, respectively. The resistivity was found to be lowest in samples sputtered with 10% N 2 /Ar and increase with nitrogen content in samples deposited with 10% to 60% N 2 /Ar. For Cu layers deposited on these films, the growth orientations were found to depend strongly on the microstructures of underlying Ta and Ta-N films. The Cu ͑111͒/͑200͒ ratio was decreased with the nitrogen content of Ta-N films.

Simultaneous occurrence of multiphases were observed in the interfacial reactions of ultrahigh vacuum deposited Hf and Cr thin films on (111)Si by high-resolution transmission electron microscopy in conjunction with fast Fourier transform diffraction analysis and image simulation. For Hf/Si system, an amorphous interlayer, Hf5Si3 as well as FeB and CrB types of HfSi were found to form simultaneously in samples annealed at 530 °C for 40–80 min. For Cr/Si system, an amorphous interlayer, Cr5Si3, CrSi, and CrSi2 were observed to form in samples annealed at 375 °C for 30 min. The formation of multiphases appeared to be quite general in the initial stages of interfacial reactions of ultrahigh vacuum deposited refractory thin films. The results called for a reexamination of generally accepted ‘‘difference’’ in reaction sequence between bulk and thin-film couples.

The behaviors of fluorine in BF~ implanted polycrystalline silicon (poly-Si) on silicon have been investigated in the annealing temperature range of 850 to 1100~ The distribution of fluorine atoms as functions of temperature and time have been monitored by the secondary ion mass spectroscopy (SIMS) and cross-sectional transmission electron microscopy (XTEM). The XTEM micregraphs revealed that fluorine bubbles are distributed in the poly-Si and at the original poly-Si/ Si interface after annealing. The locations of bubbles were found to correspond to the fluorine peaks in the SIMS depthconcentration profiles. The presence of the boron peak at the original poly-Si/Si interface is attributed to the gettering of boron atoms by the fluorine bubbles. Moreover, the boron profiles in the silicon substrates are sensitive to thermal budget due to the pileup of fluorine atoms at the pely-Si/Si interface. The pileup of fluorine at the poly-Si/Si interface leads to an enhancement of epitaxial regrewth of poly-Si films and the formation of fluorine bubbles. Consequently, higher surface dopant concentration and deeper junction depth were obtained.

Simultaneous occurrence of multiphases was observed in the interfacial reactions of ultrahigh-vacuum (UHV) -deposited V and Zr thin films on (111) Si by high-resolution transmission electron microscopy in conjunction with fast Fourier transform diffraction analysis and image simulation. For the V/Si system, an amorphous interlayer (a-interlayer), V3Si and V5Si3, were found to form simultaneously in samples annealed at 500 °C for 60 min. For the Zr/Si system, an a-interlayer, Zr5Si3 as well as FeB and CrB types of ZrSi, were observed to form in samples annealed at 440 °C for 40 min. The formation of multiphases appeared to be quite general in the initial stages of interfacial reactions of UHV-deposited refractory metal and rare-earth–metal thin films on silicon. The observation of the prevalence of the formation of multiphases in the initial stages of thin film reactions called for a reexamination of generally accepted ‘‘difference’’ in reaction sequence between bulk and thin-film couples.

Low temperature in situ boron doped Si epitaxial growth by ultrahigh vacuum electron cyclotron resonance chemical vapor deposition