Control of electrical resistivity of TaN thin films by reactivesputtering for embedded passive resistors

Tantalum nitride thin films were deposited by radio frequency(RF) reactive sputtering at various N2/Ar gas flow ratios and working pressures to examine the change of their electrical resistivity.From the X-ray diffraction(XRD) and four-point probe sheet resistance measurements of the TaNx films,it was found that the change of the crystalline structures of the TaNx films as a function of the N2 partial pressure caused an abrupt change of the electrical resistivity.When the hexagonal structure TaN thin films changed to an f.c.c.structure,the sheet resistance increased from 16 Ω/sq to 1396 Ω/sq.However,we were able to control the electrical resistivity of the TaN thin film in the range from 69 Ω/sq to 875 Ω/sq,with no change in crystalline structure,within a certain range of working pressures.The size of the grains in the scanning electron microscopy(SEM) images seemed to decrease with the increase of working pressure.