Semiconductor integrated circuit device and method for producing the same

摘要

A capacitive element has improved electrical properties. The capacitive element is configured in a DRAM cell and has a lower electrode, a capacitive insulator film formed over the lower electrode, and an upper electrode formed over the capacitive insulator film. The upper electrode has a structure in which from the capacitive insulator film side of this electrode, a first upper electrode, a second upper electrode and a third upper electrode are stacked in turn. The third upper electrode is a tungsten film that may contain an impurity. Between the first and third upper electrodes, the second upper electrode is interposed which is a barrier film for preventing the possible impurity in the third upper electrode from diffusing into the capacitive insulator film.

主权项

1. A semiconductor integrated circuit device, comprising a plurality of DRAM cells each comprising a selective MISFET and a capacitive element that are coupled in series to each other,
the device comprising: a semiconductor substrate, a first insulator film formed over a main surface of the semiconductor substrate, and having a capacitor-forming trench comprising a side wall and a bottom surface, a lower electrode formed along/over the side wall and the bottom surface comprised in the capacitor-forming trench, a capacitive insulator film formed over the lower electrode to cover the lower electrode, a first upper electrode formed over the capacitive insulator film to cover the capacitive insulator film, a second upper electrode formed over the first upper electrode to cover the first upper electrode, a third upper electrode formed over the second upper electrode to cover the second upper electrode, and having a smaller electric resistivity than the first upper electrode and being allowable to contain an impurity, wherein the capacitive element comprises the lower electrode, the capacitive insulator film, and an upper electrode comprising the first upper electrode, the second upper electrode and the third upper electrode, and wherein the second upper electrode is a bather layer for preventing the possible impurity contained in the third upper electrode from diffusing into the capacitive insulator film.