Peak-valley roughness

The substrate surface smoothness is critical to TFT performance. Device fabrication processes basically duplicate and/or worsen the surface roughness, which leads to smaller pentacene grains and results in deterioration of pentacene channel mobility. Atomic-force microscopy was used to characterize the surface roughness. Figure 15.21 shows an AFM image of our PET substrate surface before any process. The mean-square roughness and peak-to-valley roughness are 10 A and 90 A,... 

The contact deformation of these thermoplastic polymers was studied experimentally by pressing polymeric balls (of 4 mm diameter) with continuously increasing load (0.6 N/s) against an optically smooth glass surface and measuring both contact deformation displacement and contact size under load as described above (see Figure 1). The polymer balls had a mean peak-to-valley roughness of 0.6 - 1.0 im and a c.l.a. 

Figure 4 shows a functional correlation of the first kind. The feed per revolution is regressed with the peak-to-valley roughness in turning. The deviation between the theoretical and actual roughness is shown. It appears that the minimum roughness that could be achieved would be an of about 1.5 pm. 

Functional Correlation, Fig. 4 A functional correlation of the first kind showing theoretical and measured peak-to-valley roughness, Rz... 

Peak-to-valley roughness Root mean square... 

Fig. 19.6 Relationship between surface roughness and stock removal. (Reactive gas He SFe 02 = 98.9 1 0.1, RF power 8 kW, machining gap 0.3 mm.) (PV is the peak-to-valley roughness and Ra is the centerline average roughness.)...

The surface characterization (a quantitative measure of OP) was carried out by using a Zygo NewView microscope. A three dimensional profile of the samples surface and the surface roughness, the root mean square (rms) and maximum peak-valley depth (PV) were obtained. 

The presence of well-defined peaks and valleys in I-V curves indicates that LEED is indeed not a purely two-dimensional surface diffraction technique. There is a finite penetration and diffraction takes place in the first 3 to 5 atomic layers. The depth of penetration affects peak widths markedly the shallower the penetration, the broader is the diffraction peak. By simulating such I-V curves numerically with the help of a suitable theory, it is often possible to determine the relative positions of surface atoms (including therefore bond lengths and bond angles) " it may also be possible to indicate roughly the thermal vibration state of surface atoms l However, a chemical identification of the surface atoms is not possible with LEED. 

Profile - Surface profile is a measure of the roughness of a surface which results from abrasive blast cleaning. The height of the profile produced on the surface is measured from the bottom of the lowest valley to the top of the highest peak. 

In this chapter, we will be skimming the rough topology of organosilicon chemistry, and thus, we will give only the peaks of the highest mountains and completely miss the valleys and often exclude the smaller hills. Our purpose is not to be exhaustive but simply to prepare the reader for some of the material that lies ahead in this volume, and we hope to whet your interest in what we believe is a most fascinating and important subject. 

In the analysis of heat conduction through multilayer solids, we assumed perfect contact at the interface of two layers, and thus no temperature drop at the interface. This would be the case when the surfaces are perfectly smooth and they produce a perfect contact at each point. In reality, however, even flat surfaces that appear smooth to the eye turn out to be rather rough when examined under a microscope, as shown in Fig. 3-14, with numerous peaks and valleys. That is, a surface is micmscopically rough no matter how smooth it appears to be. 

Tolerances for the surface finish of tooling are also specified by manufacturers and in international standards, see Fig. 23. Any roughness of the finishing is below 1 pm peak-to-valley height, and particularly punch-tip faces and die bore walls are polished to achieve lower tolerances. 

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