Resolution depth

The prototype described in this work uses NdFeB permanent magnet blocks of 40 x 45 x 50 mm3 along x, y and z, respectively, placed on an iron yoke 25 mm thick. The gap dB was set to 14 mm, and ds was determined to be 2 mm by 

The slice selection procedure can be combined with a number of pulse sequences to spatially resolve NMR parameters or to contrast the profiles with a variety of filters. The most commonly used acquisition schemes implemented to sample echo train decays are the CPMG [(jt/2)0—(Jt)90] or a multi-solid echo sequence [(jt/ 2)0-(jt/2)9o]. In these instances, the complete echo train can be fitted to determine 

To reduce the permeation of specific compounds through plastic sheets, barriers are introduced in multi-layer structures. Each layer provides its own performance in terms of heat sealing, barrier properties, chemical resistance, stiffness, etc., and 

A nominal spatial resolution of 50 pm was set, acquiring an echo window 20-ps long. The position of the sensor was moved in steps of 25 pm requiring 160 points to cover the complete sample thickness. Using 512 scans per point and a repetition time of 150 ms the acquisition time per point was 75 s. 

The skin layers from the palm of the hand were scanned in vivo. A CPMG sequence was applied to sample the echo train decays as a function of depth. The decay was determined by both the relaxation time and the diffusion coefficient. To improve the contrast between the layers, a set of profiles was measured as a function of the echo 

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This approach is more close to X-ray stereo imaging and caimot reach enough depth resolution. There are also several systems with linear movement (1-dimensional) through the conical beam [5] as shown in Fig.4. In this case usable depth and spatial resolution can be achieved for specifically oriented parts of the object only. 

During testing a depth resolution of 50-80 micron and a lateral resolution of 20-40 micron was achieved. The spatial resolution was limited not mainly hy source or camera properties, but by the accuracy of compensation of the instrumental errors in the object movements and misalignments. According to this results a mote precision object rotation system and mote stable specimen holding can do further improvements in the space resolution of microlaminography. 

Table 1 several applications, frequencies and thickness / depth resolution... 

The discussion of Rutherford backscattering spectrometry starts with an overview of the experimental target chamber, proceeds to the particle kinematics that detennine mass identification and depth resolution, and then provides an example of the analysis of a silicide. 

Depth sensitivity is an equally important consideration in the analysis of surfaces. Techniques based on the detection of electrons or ions derive their surface sensitivity from the fact that these species cannot travel long distances in soflds without undergoing interactions which cause energy loss. If electrons are used as the basis of an analysis, the depth resolution will be relatively shallow and depend on both the energy of the incident and detected electrons and on characteristics of the material. In contrast, techniques based on high energy photons such as x-rays will sample a much greater depth due... 

The physical techniques used in IC analysis all employ some type of primary analytical beam to irradiate a substrate and interact with the substrate s physical or chemical properties, producing a secondary effect that is measured and interpreted. The three most commonly used analytical beams are electron, ion, and photon x-ray beams. Each combination of primary irradiation and secondary effect defines a specific analytical technique. The IC substrate properties that are most frequendy analyzed include size, elemental and compositional identification, topology, morphology, lateral and depth resolution of surface features or implantation profiles, and film thickness and conformance. A summary of commonly used analytical techniques for VLSI technology can be found in Table 3. 

Another confusing issue is that of depth resolution. It is a measurement of the technique s ability to clearly distinguish a property as a function of depth. For example a depth resolution of 20 A, quoted in an elemental composition analysis, means that the composition at one depth can be distinguished from that at another depth if there is at least 20 A between them. 

Depth resolution Lateral resolution Sample requirements... 

Lateral resolution Depth profiling Depth resolution Maximum depth Imaging/mapping... 

Depth resolution Quantification Lateral resolution Destructive... 

Sputtered Neutral Mass Spectrometry (SNMS) is the mass spectrometric analysis of sputtered atoms ejected from a solid surface by energetic ion bombardment. The sputtered atoms are ionized for mass spectrometric analysis by a mechanism separate from the sputtering atomization. As such, SNMS is complementary to Secondary Ion Mass Spectrometry (SIMS), which is the mass spectrometric analysis of sputtered ions, as distinct from sputtered atoms. The forte of SNMS analysis, compared to SIMS, is the accurate measurement of concentration depth profiles through chemically complex thin-film structures, including interfaces, with excellent depth resolution and to trace concentration levels. Genetically both SALI and GDMS are specific examples of SNMS. In this article we concentrate on post ionization only by electron impact. 

Complete elemental analysis of complex thin-film structures to several pm depth, with excellent depth resolution... 

Yes, repeated laser shots sample progressively deeper layers depth resolution 50-100 nm... 

Quantification Detection limits Depth profiling Penetration depth Depth resolution Lateral resolution... 

Destructive Chemical bonding Quantification Accuracy Detection limits Depth probed Depth resolution Lateral resolution Imaging/ mapping... 

Depth resolution Minimum step Maximum step Lateral resolution Maximum sample size Instrument cost... 

Reflected Electron Energy-Loss Spectroscopy (REELS) has elemental sensitivities on the order of a few tenths of a percent, phase discrimination at the few-percent level, operator controllable depth resolution from several nm to 0.07 nm, and a lateral resolution as low as 100 nm. 

Figure 4 VEELS and Auger spectra for tiK angles of 0°, 45°, and 60° taken from a tin sample covered by a 0.5-nm oxide layer. The doublet AES peaks are the Sn (410) peaks while the singlet AES peak is the O (510) taken with the same gain. VEELS peaks are oxide related, while the Sn (410) peak is due primarily to the metallic tin beneath the oxide, illustrating the superior depth resolution of VEELS.

Rutherford Backscattering (RBS) provides quantitative, nondestructive elemental depth profiles with depth resolutions sufficient to satisfy many requirements however, it is generally restricted to the analysis of elements heavier than those in the substrate. The major reason for considering depth profiling using FIXE is to remove this restrictive condition and provide quantitative, nondestructive depth profiles for all elements yielding detectable characteristic X rays (i.e.,Z> 5 for Si(Li) detectors). 

Because a FIXE spectrum represents the int al of all the X rays created along the particle s path, a single FIXE measurement does not provide any depth profile information. All attempts to obtain general depth profiles using FIXE have involved multiple measurements that varied either the beam energy or the angle between the beam and the target, and have compared the results to those calculated for assumed elemental distributions. Frofiles measured in a few special cases surest that the depth resolution by nondestructive FIXE is only about 100 nm and that the absolute concentration values can have errors of 10-50%. 

Depth resolution depends on the (spectrally dependent) optical absorption coefficient of the material. Near-surface analysis (first 50 nm) frequendy can be per-... 

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