Depth of etching

It is certainly conceivable that some ultra-sensitive method might detect damage which does not show up in any of the methods discussed. In device technology a device itself may be the best indicator of the extent of damage and the depth of etching required. 

Fig. 3.82 Pore creation through 13 tm thick PET membranes exposed to 254 and 312 nm wavelengths for 1 h. Ion beam of 58Ni with incident energy 10.7 MeV/u (1 h, 254 nm) 9.1 MeV/u (15 h, 254 nm). Etching occurs at the both faces, d is the pore diameter measured with AFM (surface image) and he is the depth of etching penetration through the membrane measured with SEM (cross-section image) and fe = etching time. Reproduced with permission from [173]. Copyright 2007. Elsevier...

Gravure printing employs an intaglio process whereby the print area lies below the surface of the plate in small cells. The tone or colour depth may rely on the depth of etch (i.e. amount of ink which lies in the cells) and/or the number of cells per linear inch. All gravure is basically half tone (solid line gravure plates are used in some tampon or cliche processes). 

The depth of etched and oxide layers with different coolants. (From Zhang, C., Ohmori, H., Kato, T., and Morita, N., Prec Eng J Int Soc Free Eng Nanotechnol, 25, 56, 2001a. With permission.)... 

ETCH factor The ratio of the depth of etch to lateral etch. 

Essentially, the technique is based on the fact that acid etches the metal away. Combined with the possibility to cover parts of steel with a protective paint, and therefore protect these areas from the acid, a relief on two levels can be produced. The decisive factor is the interaction between metal, the covering of varnish, and the acid. The exposure time determines the depth of etching. 

Figure 9.24 shows the depth of etching as a function of the relative energy density Ds and the nominal width of trenches bgs after an etching time of 60 min. The achieved etching depth corresponds to the depth to which the glass partially crystallised (Fig. 9.22). An increasing etching time will lead to the complete removal of the crystallised material. The best way to control...

If the interlace or depth of interest is beyond the capability of sputtering, one can try polishing down, sectioning, or chemical etching the sample before insertion. 

Surface features can also be revealed by etching, which permits identification of points of intersection of line dislocations with the surface, and this is valuable in determining the role of these imperfections in chemical processes [45,214] and, in particular, nucleus formation. Smaller topographical details can be rendered visible by the evaporation of a thin (<0.5 nm) film of gold onto the surface [215,216]. Heights and depths of surface features can be determined by interferometry [203—205]. Microcinematography has also been used [217] to record the progress of solid phase reactions. 

Bech Nielsen et al. (1988) also made a channeling study of the 2H in B-2H complexes that was similar in principle to that just described but differed in details of technique and in some of the conclusions arrived at. Also, they did not investigate the position of the boron atoms. They used Si uniformly doped with a high (1 x 1019 B/cm3) boron concentration, rather than implanted boron. The surface was etched off after hydrogenation, but no SIMS data was presented to confirm the uniform hydrogen concentration assumed. The penetration depth of the H was given as —7000 A. The channeling measurements were performed at 30 K. For analysis of their data Bech Nielsen et al. used the same model, based on the assumption of statistical equilibrium (SE) of the channeled ions, already described in connection with the measurements of implanted deutrium... 

The majority of micromechanical devices require 3D machining of the bulk silicon material with etching depths of up to wafer thickness. Generally, three basic etching process types can be distinguished ... 

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