Electrical resistivity and luminous reflectance of TiN films prepared by DC reactive sputtering

We have already reported that the conditions for obtaining gold-yellow TiN films by reactive sputtering method without bias application. It is well kn own that the qualitative relationship between the color and the electrical resisitivity of TiN films such as "the golden yellow TIN films have low res istivity". However the reason for this relationship is not clear. The purpo ses of the present work are to investigate the quantitative relationship be tween the colorimetric properties and electrical resistivity of these films and to examine the cause for these properties. For these purposes, the col or of the films was evaluated by means of the chromaticity coordinates, x a nd y, and the stimulus value or luminous reflectance, Y, which is an index of the brightness based on a CIE standard colorimetric system. TiN films ha ving several kinds of properties were obtained, and a study of their electr ical and colorimetric properties has provided the following conclusions: (i ) The colorimetry of the films is affected by both the mixing ratio of Ar/N -2 gas and the total gas pressure. Particularly, the luminous reflectance, Y, varied greatly with a change in total gas pressure of Ar and N-2 gas. (i i) Even without bias application, a gold-colored TiN film with higher refle ctance, Y, has been obtained by deposition at an appropriate mixing ratio o f N-2/Ar and also under lower total gas pressure, namely, rho=0.31 mu Omega m and Y=49% for the films deposited at 0.15 Pa. (iii) As the total gas pre ssure was increased, the column size, the surface roughness and oxygen cont ent clearly showed an increase. Thus, the films deposited under an atmosphe re higher than 0.15 Pa had higher resistivity and lower reflectance. (iv) B ased on our results, the quantitative relationship between the resistivity, rho, and the luminous reflectance, Y, of the TiN films is shown by the rep resentation of rho=775 Y-2.