The possibility of using nonisothermality effect in filling semi-closed channels by means of deposition of gas molecules on the inner channel surface is analyzed. The case of chemical deposition is investigated for free-molecular gas flow in the cylindrical channel with the temperature-dependent coefficient 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 substance film which is sufficiently uniform in thickness and the film with monotonous decrease in the thickness towards the exit from the channel. The last factor is important for the problem of filling the channel by the substance without formation of cavities. The possibility of realization of the above temperature distribution along the channel by means of the microwave radiation is considered.