Chemical deposition of substance from gas phase in nonisothermal channels

The possibility of using nonisothermality effect in filling semi-closed cha nnels by means of deposition of gas molecules on the inner channel surface is analyzed. The case of chemical deposition is investigated for free-molec ular gas flow in the cylindrical channel with the temperature-dependent coe fficient which characterizes the efficiency of collisions of molecules with the surface. It is shown that decrease in the surface temperature from the bottom to the open end of the channel enables one to obtain both the subst ance film which is sufficiently uniform in thickness and the film with mono tonous decrease in the thickness towards the exit from the channel. The las t factor is important for the problem of filling the channel by the substan ce without formation of cavities. The possibility of realization of the abo ve temperature distribution along the channel by means of the microwave rad iation is considered. (C) 2000 Elsevier Science Ltd. All rights reserved.