Metal-insulator-metal capacitor for use in semiconductor devices and manufacuring method therfor

摘要

The present invention is related to a method for producing a stack of layers on a semiconductor substrate (1), including a bottom metal layer (10), an intermediate dielectric layer (11) and a top metal layer (12). The stack is suitable for producing metal-insulator-metal capacitor structures. According to the preferred embodiment, the bottom metal layer is a ruthenium layer (10b) covered by a ruthenium oxide layer (10a) obtained through controlled oxidation of the Ru layer. According to the invention, the dielectric layer is obtained by first depositing a thin TiO 2 protection layer (11a) by atomic layer deposition using water as oxidant, followed by deposition of a second dielectric (11b) through ALD using O 3 as oxidant. Preferably the second dielectric is a TiO 2 layer in rutile phase. The thin protection layer protects the Ru from etching by O 3 , while allowing easily the formation of rutile phase TiO 2 . The invention also reveals a method for oxidizing a Ru layer in such a manner that the roughness of the Ru layer remains unchanged.