RBS spectrum

Figure 2 RBS spectra from two TaSi , films with different Si /Ta ratios and layer thicknesses.

Figura 3 Crystal channeled RBS spectra from Si samples implanted with 10, and...

Figure 4 RBS spectra from a sample consisting of 240 nm of Si on 170 nm of Si02 on a Si substrate. The spectrum in (a) was acquired using a scattering angle of 160° while the spectrum in (b) used a detector angle of 110°. This sample was implanted with 2.50 x 10 As atoms/cm, but the Aa peak cannot be positively identified from either spectrum alone. Only As at a depth of 140 nm will produce the correct peak in both spectra.

Sample roughness also can produce problems in the interpretation of RBS spectra that are similar to problems encountered by sputtering techniques like AES,... 

Figure S ERS and RBS spectra for a 1000-A sputtar-deposKed diamond-like carbon film on Si. Both spectra are required for complete analysis.

Fig. 3.49. RBS spectra from GaAs implanted with Si (120 keV, 5 x lO cm before and after annealing at 950 °C. The uppermost spectrum is taken in a random direction, the others are in the channeling direction [3.127],...

Fig. 3.50. RBS spectra of buried (5 -FeSi2 (full line) and /J-FeSi2 (dotted line) layers taken in a random direction. The <111 > channeling spectrum (circles) refers to the /J-FeSi2 layer [3.130],...

RBS and channeling are extremely useful for characterization of epitaxial layers. An example is the analysis of a Sii-j Gejc/Si strained layer superlattice [3.131]. Four pairs of layers, each approximately 40 nm thick, were grown by MBE on a <100> Si substrate. Because of the lattice mismatch between Sii-jcGe c (x a 0.2) and Si, the Sii-j Ge c layers are strained. Figure 3.51 shows RBS spectra obtained in random and channeling directions. The four pairs of layers are clearly seen in both the Ge and Si... 

Fig. 3.51. RBS spectra of 2.07 MeV He ions back-scattered from a Sii-xdex/Si strained layer superlattice.

An example of this process of data analysis is provided by the work of Yubero et al. (2000), who studied the structure of iron oxide thin films prepared at room temperature by ion beam induced chemical vapour deposition. Such films find important applications because of their optical, magnetic, or magneto-optical properties. They were produced by bombardment of a substrate with Oj or Oj + Ar+ mixtures, and Figure 4.15 shows RBS spectra of two iron oxide thin films prepared on a Si substrate by each of these bombardment methods. 

Mossbauer spectra were recorded for the same samples four species for Fe3+ and two for Fe2+ were distinguished. The relation between their relative proportions and crystallization time are shown in Figs. 2A and 2B. RBS spectra are shown in Fig 2C. 

Figure 2. Relative amounts of various iron species deduced from 57Fe Mossbauer spectra of the Fe-exchanged samples shown in relation to the progress of the hydrothermal crystallization process at 80°C (A), 57Fe Mossbauer spectra of the Fe-exchanged samples after 0 (a), 120 (b), 180 (c) and 240 min (d) of the hydrothermal crystallization process at 80°C (B) and RBS spectra collected on five different particles of the sample crystallized for 240 min (C). The position of surface Fe in Fig. 2C is marked by the vertical arrow. Depth scale (depth into each particle) is increasing toward left (marked with the horizontal arrow). Fit to experimental data with assumed homogeneous depth distribution of Fe is marked with the continuous line.

Figure 4.16 RBS spectra of an MoOt model catalyst supported on a flat SiO2/Si(100) model support, before and after sulfidation in a mixture of H2S and H2 at room temperature, and at 300 °C (courtesy of LJ. van IJzendoom, Eindhoven [21J).

RBS spectra were obtained using a 2.120 MeV He+2 ion beam at a backscattering angle of 162. The spectra were accumulated for a total ion dose of 40 uC using a 10 nA beam current. The number of Ti atoms/cm2 in the sample was calculated by comparison to spectra for a standard Si wafer implanted with a known dose of Sb. 

Figure 5. RBS spectra of a m-cresol novolac film treated with TiCU for 2 mins, (dotted line) and then etched for 30 mins, by O2 RIE (solid line).

Figure 6. RBS spectra of a PMMA film treated with TiCU for 2 mins.

RBS spectra of a poly(styrene) film treated with TiCLj for 2 minutes. 

Figure 5. RBS spectra obtained from near random and aligned orientations for pulsed-laser annealed, As ion-implanted Si. (Reproduced, with permission, from Ref. 46. Copyright 1981, Journal of Applied Physics.,)...

Figure 31 RBS spectra and depth profile for aluminum with implanted antimony.

For thin film samples the analysis of the RBS spectra is generally straightforward, especially when the peaks are well separated. For bulk samples and samples with layers of different compositions the spectrum will be a complicated sum of the individual element spectra. For analysis, a model spectrum is generated based on assumptions about the elemental composition and element distribution in the sample. The model parameters are (manually or by a minimisation routine) adjusted until a satisfactory agreement with the measured spectrum is obtained. 

Data Analysis. For both the macro- and micro-PIXE systems an on line display of the X-ray and RBS spectra is provided by an LSI 11/23, while detailed analysis of the RBS and PIXE spectra are performed using the programs RUMP (1L) and MENUGF (UL) The latter analyzes the 1024... 

Figure 5. The PIXE and RBS spectra from a target of NBS standard liver mounted on a thin Kimfol backing.

Instrumental Techniques. Ion beam irradiation of samples was performed by focusing 2.1 MeV He2+ ions, using an Ionex Tandetron accelerator, to a spot size of approximately 4 mm2. Ion beam currents were held constant at 10 nA. Radiation effects were determined by varying the total charge on the sample between 0 and 20 pC. RBS spectra were collected with the samples at an angle of 45° with respect to the incident beam additional instrumental details can be found elsewhere (20). Spectral simulations were performed using the RUMP method designed by Doolittle (21). 

The use of helium ion beams for conventional RBS analysis allows the detection of elements with atomic numbers greater than two with computer simulation, atomic ratios and distribution depths can be calculated. Figure 1 shows RBS spectra for an untreated PTFE film and a PMDA-ODA film after treatment in a CF rich microwave plasma. 

Figure 1. RBS Spectra of (a) PTFE Film, and (b) PMDA-ODA film exposed 30 minutes to 85% CF.,/15% 02 Plasma. Solid lines represent the simulated spectra.

Fig. 22 RBS spectra of carbonitride films deposited, at different temperatures, using IBAD technique.

Figure 22 shows RBS spectra of amorphous (Raman spectra similar to amorphous diamond like films) carbonitride films deposited at different temperatures using IBAD. Using this technique, maximum nitrogen incorporation was 33% as compared to 57% required for P-C3N4 stoichiometry. The XPS spectra (C Is and N Is) of the film with 33% nitrogen are shown in Figure 23. From these spectra the percentage of single bonded carbon and nitrogen is obtained...

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