Reactor bell jar

Bell Jar Reactor, Barrel Susceptor If we wanted to place even more wafers in a reactor, one can go to a bell jar configuration and extend the tilted susceptor tube concept just described. Consider a reactor within a bell jar arranged as shown in Figure 21. 

Figure 21 Bell jar reactor, barrel susceptor, axial flow.

Bell Jar Reactor, Barrel Susceptor, Radial Flow In much the same way that we extended the tube reactor with parallel flow to a bell jar geometry, we can do the same with the tube reactor with normal flow. Consider Figure 22. Since the flow is entering radially from the outside, one way to heat the susceptor is with high powered lamps within the central cavity. Again, the susceptor could be rotated to improve uniformity. 

Pancake Reactor The tube reactor with normal flow leads to another type of bell jar reactor referred to as the pancake reactor. It is shown in Figure 23. Here the susceptor is a disc placed horizontally and heated by induction by coils placed below it. The reactive gas flow could be introduced from above, but the favored approach is to introduce it from below at the center of the susceptor disc. Gas exhaust is at the periphery between the disc and the bell jar. 

Concerning the design factors of reactors, Liepins and Sakaoku [7] stated that of the three polymerization chambers investigated (including a bell jar reactor in addition to two reactors shown in Figures 8.12 and 8.13), the design depicted in... 

Powder formation is therefore highly system dependent. For example, in the bell jar reactor used by Kobayashi et al. [10], acetylene always forms powders as depicted in Figure 8.18, whereas coherent films are always obtained from acetylene... 

In DC cathodic polymerization conducted in a bell jar reactor, the cathode (substrate) is positioned in the middle between the two anodes. In such electrode arrangement, the distance between the cathode and the anode is expected to have some effects on the deposition rate and deposition profile with respect to those without anode assembly. Figures 13.4 and 13.5 show the influence of the distance between two anodes (one-half of which is the cathode-anode distance) on TMS deposition rate on cathode (i.e. substrate) and anode, respectively. 

Figure 15.23 Schematic diagram of the bell jar reactor system.

An important implication of the data obtained with both a tubular reactor and a bell jar reactor is that the polymer deposition onto a stationary substrate cannot be uniform due to the diffusional transport of polymer-forming species and the path-dependent growth mechanism. The variation of polymer deposition rates at various locations becomes smaller as the system pressure decreases because the diffusional displacement distance of gaseous species increases at lower pressure. It is important to recognize that a certain degree of thickness variation always exists when the plasma polymer is deposited onto a stationary substrate regardless of the type of reactor and the location of the substrate in the reactor. 

The most common way to deposit the Si is the Siemens type of deposition, where the Si is deposited on a Si filament in a bell jar reactor. For deposition of Si from TCS, typically a temperature of 1100°C is applied on the seed rods. The deposition is carried out inpresence of hydrogen, and the reaction... 

The effect of the direction of flow on deposition rate distribution has received some attention. The effect of the position of the monomer inlet in a capacitively coupled bell-jar reactor has been studied [41, 52]. In the latter work, the position of the inlet was found to affect the efficacy of the resultant plasma polymer as a reverse osmosis membrane. 

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