The stylus profiler

Thickness Measurement. The thickness of poly(I) at different coverages was obtained using a Tencor alpha-step 100 surface profile measuring system. Electrodes used were glass slides coated with Pt by electron beam evaporation. In order to produce a "step" across which the stylus of the surface profiler was drawn, Apiezon N grease was applied to part of the electrode surface and was removed with CH2CI2 after derivatization with poly(I). 

An excellent way to create standards is ion implantation of the elements of interest into the matrix. This works exceptionally well for semiconductors since one can usually start with high-purity single-crystal materials that represent the matrix of interest. Also the use of Eq. (4.8) is well suited for this purpose since ion implanters usually quote doses in atoms per square centimeter. However, Eq. (4.5) serves just as well by converting the matrix concentration to atoms per cubic centimeter. In this procedure, the implant profile is sputtered through, the implant element secondary ions and the matrix element secondary ions are each summed, and the depth of the sputter profile is determined, usually by using a stylus profilome-ter. The sensitivity factor is then calculated from... 

Samples returned to the laboratory after exposure are measured by micrometer prior to laser-moire evaluation micrometer measurements are reproducible only to within 13 micrometers because surface roughness produces an unusually high sensitivity of measurements to placement of the micrometer. Following laser-moire measurements, the samples have in some instances been checked by an electronic dial gage profiling technique. Because there is risk of damage to samples by the stylus of the gage, its use is minimized thus, the statistics are fewer than desired and far less comprehensive than those of the completely nondestructive laser-moire method. Samples are returned to test sites for continued exposure after measurements. 

The reference line xx is established by the skid as it slides along supported by the crests of the peaks meanwhile the profile of the surface is generated by the vertical excursions of the stylus, yy, in conjunction with the horizontal movement in the x-direction. To convert these raw data into a statistical average with a symmetrically distributed deviation, the reference line xx must be translated so that the area bounded by the profile curve over the length L is equally distributed on both sides of the line, as in Fig. 12-5. Statistical treatments of surface profile data are discussed at length in Sections 12.3 and 12.4. 

For the measurement of machined surfaces, mostly two-dimensionally working tactile stylus instruments are applied. At this a stylus tip (as a rule made of diamond) is moved along the surface, and its displacement against a reference plane is measured. The obtained profile finally is treated mathematically. On mild surfaces, the stylus tip may leave marks, which is a disadvantage of tactile measuring methods. 

The vertical motion of the stylus or optical system is converted into an electrical signal, which may be processed to present results in several different ways. A common form of output of a profilometer is a surface profile graph. Magnifications appropriate to the texture may be chosen, but in order to display the relatively fine features of roughness, the vertical... 

Contact systems use a stylus that moves across the film at a selected rate of speed. The position of the stylus is detected, and the profile may be plotted as the stylus moves. These can be quite sensitive when the profilometer is placed on a steady table and shielded from air currents. Contact systems may only be used on dried and fired prints. The output from these systems may be plotted graphically or may also be integrated, as for the laser, to provide a mean thickness. 

The equipment stylus, hence the measured profile, does not in general pass exactly at the summit of a peak. The measured profile does not exactly correspond to the surface summits. Nayak [11] proposes that, for random surfaces, the density of the summits, Ti, is equal to 1.2 times the square of the density of peaks. Dp, r = 1.2 Dp Because the studied surfaces are not random, we chose to consider that ii = Dp. It was assumed that the surface is isotropic and the density was calculated by ... 

In past years, a contacting-stylus instrument similar to a phonograph needle has been the standard method for surface-profile measurements. A fine diamond stylus coupled to a transducer scans the surface, providing closely spaced profiles that can be displayed on an x-y recorder. The elevation sensitivity is excellent but unfortunately the stylus sometimes obliterates the original surface features. The diameter of the stylus point determines the width and depth of the crevices it will measure. Table 2 compares the vertical and horizontal resolving powers of several microtopography techniques. The other electron techniques mentioned in Table 2 will be discussed in later sections. 

Every material sputters at a characteristic rate, which can lead to significant amb ity in the presentation of depth profile measurements by sputtering. Before an accurate profile can be provided, the relative sputtering rates of the components of a material must be independently known and included, even though the total depth of the profile is normally determined (e.g., by stylus profilometer). To first order, SNMS offers a solution to this amb ity, since a measure of the total number of atoms being sputtered from the surface is provided by summing all RSF- and... 

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