Electrical and colorimetric properties of TiN thin films prepared by DC reactive sputtering in a facing targets sputtering (FTS) system

The aims of the present work are twofold: first, to confirm the condition f or obtaining gold-yellow TIN films without bias application; second, to exa mine the quantitative relationship between the colorimetric properties and electrical resistivity of these films. For the first aim, TIN films were pr epared by DC reactive sputtering under a no-bias condition in the facing ta rgets sputtering (FTS) apparatus, in which discharge is maintained even at a low gas pressure of less than 0.3 Pa. For the second aim, the color of th e films was evaluated by means of the chromaticity coordinates, x and y, an d the luminance factor Y,which is an index of the brightness based on a CIE standard colorimetric system. Gold-yellow TIN films having low resistivity were obtained, and a study of their electrical and colorimetric properties has provided the following conclusions. (i) The colorimetry of the films i a affected by both thp mixing ratio and total gas pressure. In particular, the brightness (the luminance factor) Y varied greatly with a change in tot al gas pressure. (ii) Even without bias application, a gold-colored TIN fil m with higher brightness Y has been obtained by deposition at an appropriat e mixing ratio of N-2/Ar and also under lower total gas pressure (rho=0.31 mu Omega m and Y = 49 for the films deposited at 0.15 Pa). (iii) As the tot al gas pressure was increased, the column size, the surface roughness and o xygen content showed a clear increase. Thus, the films deposited under an a tmosphere higher than 0.15 Pa had higher resistivity and lower brightness. (iv) Based on our results, the quantitative relationship between the resist ivity and brightness of the TiN films is shown by the relation of rho=775Y( -2). (C) 1999 Elsevier Science S.A. All rights reserved.