Substrates microelectronic fabrication

Chemical vapor deposition is a key process in microelectronics fabrication for the deposition of thin films of metals, semiconductors, and insulators on solid substrates. As the name indicates, chemically reacting gases are used to synthesize the thin solid films. The use of gases distinguishes chemical vapor deposition (CVD) from physical deposition processes such as sputtering and evaporation and imparts versatility to the deposition technique. 

Cold wall reactors are the other major category of CVD reactors. In such systems, the substrates are heated but the walls are cooled. Figure 9 shows an example of a cold wall rotating disk CVD reactor.This system has water-cooled quartz walls, with a rotating holder for (silicon or compound semiconductor) wafers that is resistively heated from below. Other commercial cold-wall reactors include lamp heated single-wafer reactors that are widely used in microelectronics fabrication, and inductively heated horizontal flow reactors. Cold-wall reactors are often run at relatively high pressures, several hundred torr to atmospheric total... 

Data obtained from STM images can be useful in providing information on the relative importance of molecule-molecule and molecule-substrate interactions, as well as the types of forces responsible for the packing order at the surface. This is useful in such applications as epitaxial growth of thin films, chromatography, lubrication, and microelectronics fabrication, each of which involves interactions between molecules on a surface and can be investigated by these procedures. 

Ellinas, K., Smyrnakis,A., Malainou, A.,Tserepi, A., Gogolides, E., 2011. Mesh-assisted colloidal lithography and plasma etching a route to large-area, uniform, ordered nano-piUar and nanopost fabrication on versatile substrates. Microelectron. Eng. 88,2547. 

The rotating-disk CVD reactor (Fig. 1) can be used to deposit thin films in the fabrication of microelectronic components. The susceptor on which the deposition occurs is heated (typically around lOOOK) and rotated (speeds around 1000 rpm). A boundary layer is formed as the gas is drawn in a swirling motion across the spinning, heated susceptor. In spite of its three-dimensional nature, a peculiar property of this flow is that, in the absence of buoyant forces and geometrical constraints, the species and temperature gradients normal to the disk are the same everywhere on the disk. Consequently, the deposition is highly uniform - an especially desirable property when the deposition is on a microelectronic substrate. 

The silicon substrate constitutes a very interesting support for facilitating the integration in microelectronic devices. The electrochemical and electroanalytical fields can gain remarkable benefits from the silicon-based miniaturization devices, especially if arrays of metal electrodes can be fabricated. An understanding of the electrochemical properties of CNTs directly attached to silicon is thus essential for their potential application in developing silicon-based electrochemical or (bio)electrochemical... 

Most microelectronic facilities can readily achieve minimum feature sizes on the order of 10 pm or better. State-of-the art facilities can produce devices with feature sizes of a few tenths of a micrometer. The lower limit is still decreasing, but the effort required expands exponentially as feature size decreases. Frequently, large numbers of devices can be simultaneously fabricated on the same substrate and subsequently separated by scoring and breaking or sawing the substrate after all processing steps are complete. While complex multilayer devices are possible, most film electrode devices reported to date involve only one or two layers. 

On the other hand, deposition-based waveguides usually have a squarelike geometry in a strip, a strip-loaded or a rib configuration (Fig. 6). They are fabricated by depositing several layers onto a planar substrate by means of microelectronic processes, covering and etching them until the final geometry is obtained. 

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