Implanted layers implant profile

In the first case, open symbols, a thin skin layer was created by an etch treatment. The second case shows a sample capped with a 200 nm thick cap. Either treatment seals the surface and prevents the escape of positronium. Below the surface layer, significant porosity can be observed. However, because the implantation profile is spread across larger depth regions in the second case, a careful data analysis must be undertaken to extract the actual porosity. 

Other near-suiface applications have included the implantation profiles of phosphorus in iron and FeO [283] TiN and copper coatings on steel [284] chromate layers on aluminum [285] and implantation profiles of phosphorus and boron in iron and nickel [286]. 

Figure 1. Ion implantation process and resulting alterations in the near-surface layers ion profile and damage protilc.

The implanted layer is thin, typically between 0.1 and 1 pm in depth. Impurities such as C and H often follow the implantation profile. 

An example of the distribution of implanted atoms is given in Fig. 17 for the profile of CO implantation, as measured by HEBS. The maxima of implanted C (29 at.%) and O (23 at.%) are reached at a depth of ca. 170 nm with a FWHM of the layer of ca. 200 nm. Due to the large cross sections the yields of C and O are strongly enhanced with respect to that of the substrate. The formation of an oxide layer in air after implantation leads to an O concentration at the surface higher than in the implanted layer. It can also be seen that the implantation profiles are nonzero at the surface, implying that there are implanted atoms in the outer surface layers, an observation that turns out to be important for the wear process. 

Fig. 5. Bipolar transistor (a) schematic and (b) doping profiles of A, arsenic ion implanted into the silicon of the emitter ( -type) B, boron ion implanted into the silicon of the base (p-type) C, antimony ion implanted into the buried layer ( -type) and D, the epi layer...

Figure 7 SIMS depth profile of Si implanted into a 1- im layer of Al on a silicon substrate for 6-keV O2 bombardment The substrate is B doped.

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.

Equation (10.1) can be used to determine the doping density of a silicon substrate and its depth profile, even if the flat band potential is not known accurately. Diffusion doping, ion implantation or the growth of an epitaxial layer are common methods of producing doped regions in semiconductor substrates. The dopant concentration close to the surface can be measured by SRP or capacitance-... 

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