SIM profiles

Figure 3 Depth profiles of F implanted into 2000 A Si on Si02 la) SALI profile with Ar sputtering and 248-nm photoionization and (b) positive SIMS profile with O2 sputtering. Analytical conditions SALI, SiF profile) 7-keV Ar, 248 nm SIMS, F profile) 7-keV02 ...

Figure. SIMS profiles showing the growth of Na at the lime where Si decreases and Ta increases, as a function of time.

Fig. 6. Spreading resistance and SIMS profile from deuterated CZ Si containing an initial uniform concentration of 6 x 1016 cm-3 thermal donors. The high, near-surface concentration is due probably to deuterium molecule formation (Pearton et al., 1986). 

Fig. 10. SIMS profiles of D in a 1.2 /xm Sio Geo 36 layer grown on a Si substrate and exposed to a D plasma for 30 min. at various temperatures.

Here N0 is the initial concentration of centers, v is the attempt frequency, and Ea the binding energy. For As—H and Sb—H samples it was observed that the concentration of centers initially increased upon annealing. It was supposed that the excess hydrogen that is often observed in SIMS profiles at the surface of n-type samples might be causing this anomalous increase. 

The IBM group (Marwick et al., 1987, 1988) studied both the boron and deuterium sites in B-2H complexes using the 2H(3He, pa) and 11B(1H, a) nuclear reactions respectively. The optimum results were obtained with a 30 keV B implant of 1015 cm-2. Figure 8 shows SIMS profiles of the 2H and nB in a typical sample used in their work. A near-surface layer with excess hydrogen remains even after etching off 1000 A of the surface (the figure shows SIMS data from the etched sample). Deeper in, the B and H concentrations are the same within the error in the SIMS calibration, consistent with B—H pair formation. The horizontal lines on the plot show... 

Fig. 8. SIMS profiles of 2H and nB in plasma-passivated B-implanted and annealed samples used in channeling studies of B—H complexes by Marwick et al. (1988). 1000 angstroms was etched off the surface of this sample to eliminate a layer containing a large excess of hydrogen. Nevertheless, some excess over the boron concentration remains at shallow depths. The histogram shows the deuterium profile used to analyze the data using calculated flux profiles.

Fig. 20. SIMS profiles of total deuterium density across p-n junctions formed by implanting phosphorus into a (100) silicon water uniformly doped with 1 x 1017 boron atoms per cm3 for various times of deuteration at 150°C (Johnson, 1986a). The phosphorus profile is also shown and serves to locate the pre-deuteration depth of the junction at 0.5 Deuteration was from downstream gases from a plasma discharge (Johnson and Moyer, 1985).

Figure 21 shows, for specimens similar to those of Fig. 20, the SIMS profiles of total deuterium and the distribution of deuterium taking part in acceptor passivation as obtained by C-V profiling for two conditions of deuteration. Both involved one hour exposure to plasma discharge products at 200°C, but one was with zero bias applied to the junction during this time, the other with 10 V reverse bias. The main features of these... 

Fig. 22. SIMS profiles of total deuterium density in three composite samples subjected to two hour deuteration in the same plasma product environment at 300°C (Johnson, 1987). All samples had a substrate containing 8 x 1018 B/cm3 this was covered with expitaxial layers containing respectively 8 x 1018, 3 x 1018, and 5 x 1017 As/cm3, as labeled, producing n-atop-p junctions. 

Fig. 25. SIMS profiles of total deuterium density in n-type silicon (1 x 1017 phosphorus per cm3) deuterated hour by plasma products at 150°C, and modification of this density profile in identically prepared specimens subjected to various subsequent annealings in vacuo (Johnson and Herring, 1988b). 

Fig. 27. SIMS profiles of the total deuterium density produced by exposing near-intrinsic silicon (pa 100 flcm) to plasma products at various temperatures (Johnson, 1987, 1988 Corbett et al., 1988 a,b).

Fig. 28. SIMS profiles of the deuterium distribution in a sample of (100) silicon after an implantation dose of 1.0 x 1016 2H/cm2 at 120 keV, and after subsequent anneals of 20 min. at various temperatures (Wilson, 1986).

The most commonly accepted model for the hydrogen-acceptor pairs locates H at the BC site (see Fig. 4). This model was originally proposed for the H—B complex on the basis of satisfied bonds to explain the increased resistivity (Pankove et al., 1983), SIMS profiles (Johnson, 1985), and a hydrogen local-mode frequency consistent with a perturbed hydrogen-silicon bond (Pankove et al., 1985 Johnson, 1985 Du et al., 1985). The acceptor deactivation by atomic hydrogen was subsequently observed for Al, Ga, and In acceptors in silicon (Pankove et al., 1984). Hydrogen local-mode vibrations were identified as well for the H—Al and H—Ga complexes (Stavola et al., 1987). The boron vibrational frequency for the H—B pair was first identified by Stutzmann (1987) and Herrero and Stutzmann (1988a). 

Secondary ion mass spectrometry (SIMS) was used to characterise the coatings for their Ti, Ru and O stoichiometry on the surface and as a function of depth into the coating. A PHI 6650 Quadrupole mass spectrometer, with Cs+ as the ion source was used in these studies. The conversion of the measured secondary ion counts to concentration was performed using relative sensitivity factors, which were first determined with a standard sample containing known amounts of RuC>2 and TiC>2. All of the SIMS profiles were repeated several times, to determine the measurement precision, which was typically +10%. 

Fig. 5.15 SIMS profiles of (A) a new anode (Ru loading of 7g m 2)and (B) a failed anode (Ru loading of 3-4 g m 2) from plant 1.

Fig. 5.19 SIMS profile of Ir02 + Ru02 + Ti02 after 1000 days of operation at plant 2. 

Figure 4.11 Random and channeled doping profiles in 6H-SiC. (a) Comparison between SIMS measurements and MD simulations for a low fluence value. (From [74], 2000 Material Science Forum. Reprinted with permission.) (b) Evolution of the SIMS profiles for channeled implants at increasing fluence values. (From [24], 1999 American Institute of Physics. Reprinted with permission.)...

As an example of typical experimental data, Fig. 10.32 is a GC-MS selected ion monitoring (SIM) profile (m/z 247) for the nitrofluoranthenes and nitropy-renes in an extract of ambient particles collected in southern California (Arey et al., 1988b). The 1-nitropyrene (1-NP) and 3-nitrofluoranthene (3-NF) presumably are from diesel emissions (Tables 10.33 and 10.34), but the dominance of 2-nitrofluoranthene and 2-nitropyrene reflects a second major source. 

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