Elimination of low temperature ammonia salt in TiCl4NH3 CVD reaction

摘要

A cold wall CVD reactor, particularly one for use in depositing TiN in a TiCl4+NH3 reaction, is provided with a metallic liner insert in partially thermally insulated from the reactor wall which serves as one plasma electrode to form a weak secondary plasma when energized along with a second electrode near the vacuum exhaust port of the reactor. The plasma, in cooperation with radiant lamps provided to heat a wafer substrate onto which the primary CVD film is to be applied, heats the liner and a portion of the space adjacent the reactor walls and susceptor surfaces downstream of the reaction volume to cause the formation of deposits to be of the nature that can be removed by plasma cleaning without opening the reactor volume. Deposits such as TiNxCly and TiN form at temperatures of approximately 200 DEG C. to 650 DEG C., preferably between 300 DEG C. and 450 DEG C., rather than adduct ammonia salts of TiCl4, which would tend to form at temperatures of 200 DEG C. or less.