IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Microelectromechanical Systems (MEMS) Thursday Sessions
       Session MM-ThP

Paper MM-ThP1
Determination of the Young's Modulus and Residual Stress in 3C-SiC Films Using the Load-Deflection Technique

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Poster Session
Presenter: C.A. Zorman, Case Western Reserve University
Authors: J. Mitchell, Case Western Reserve University
C.A. Zorman, Case Western Reserve University
M. Mehregany, Case Western Reserve University
Correspondent: Click to Email
Silicon Carbide is an attractive mechanical material for MEMS due to its high Young's modulus coupled with its high temperature stability and chemical inertness. SiC is also receiving attention as a material for NEMS for these same reasons. The cubic polytype (3C-SiC) can be epitaxially grown on (100)Si substrates, thus providing an excellent opportunity for measuring the mechanical properties of SiC, since test structures can be fabricated using conventional Si bulk micromachining techniques. Using an interferometric load-deflection technique applied to bulk micromachined diaphragms, we have measured the spatial distribution of the Young's modulus and residual stress of 3C-SiC films grown on large-area (100 mm-dia.)(100) Si wafers. In addition to the spatial distribution, the run-to-run variation and the variation as a function of film thickness were also characterized. In general, we found that the Young's modulus, which averaged about 360 GPa, is insensitive to location on the wafer as well as film thickness. This is in stark contrast to the residual stress, which varied by as much as 200 MPa across a 100 mm-diameter wafer, and is, in general, higher for thinner films. This paper will detail the film growth process, and test sample preparation procedure, the testing technique, and the test results for 3C-SiC film thicknesses ranging from 0.125 to 2 microns. Issues pertaining to making measurements of high modulus films such as SiC using the load-deflection technique will also be discussed.