Stresses in Films Deposited by Planar Magnetron Sputtering on Glass Substrates of Different Thickness
- PDF / 335,556 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 94 Downloads / 223 Views
STRESSES IN FILMS DEPOSITED BY PLANAR MAGNETRON SPUTTERING ON GLASS SUBSTRATES OF DIFFERENT THICKNESS Zhi-Feng ZHOU AND Yu-Dian FAN Department of Materials Science University, Beijing, CHINA
and
Engineering,
Tsinghua
ABSTRACT Stresses affect the structure and properties of the films significantly. In this paper, Co-Cr films were deposited by D.C. planar magnetron sputtering on rectangular glass plates of thickness varied from 0.18 to 2.00mam. The measurement of stress was performed by the bending plate technique with the detection of capacitance change. The temperature of the bending plate waa measured by an Fe-Ni thin film thermocouple on the back side of the substrate. The experimental results showed that the stresses were all tensile, but in the films on the thicker substrates were smaller than that on the thinner ones. And apparently the temperature rise of the thicker substrates during deposition was lower than that of the thinner ones. The magnetic characteristics of the Co-Cr films related to the substrate thickness may be attributed to both stress and temperature difference in the films deposited on the substrates of different thickness. INTRODUCTION In recent years, as an applicable perpendicular magnetic recording medium, Co-Cr films are being studied widely [1], but few
attention
has been paid to their mechanical properties
such
as internal stress. Desserre e t a i.[2] for the first time found an interesting phenomenon that the perpendicular coercivity and the C-axis orientation of Co-Cr films had some relation with the thickness of substrates on which the films were deposited, but the reason was not made certain. In this paper, the dependence of the structure and the magnetic properties of Co-Cr films on the thickness of substrate was also found. For the purpose of investigating this phenomenon,the surface temperature and the stress of the films were measured respectively. EXPERIMENTAL PROCEDURE Among many techniques for the measurement of stress in thin films, the cantilevered beam technique is widely used, especially in the case for evaporated films (3]. In general, the small deflection of the free end of the cantilevered beam is detected optically or capacitively, and the latter is more sensitive. Unfortunately, the capacitive detection can not be applied as an in situ stress measurement method to sputtered films because of the serious interruption of glow discharge, but the stress can be measured after sputtering. By the bending beam technique, the stress in a film, 5, can be calculated by the following well known formula[4]1 S.EsH'8 /3(1-v )L'f
Mat A.s. Soc€. Syrup. Proc. Vol. 130. ©1iN9 Materil~s Raeamrch Society
(1)
384
where 6 is the deflection of the free end of the cantilevered beam (or plate), f is the film thickness, L and H are the length and the thickness of the substrate respectively, and Es and v ratio of the modulus and the Poisson' s are the Young' s substrate material respectively ( here v is taken to be 0.22 ). The deflection of the free end, 6 , can be detected by the c
Data Loading...
