Measurement of Young’s modulus and residual stress of thin SiC layers for MEMS high temperature applications

Abstract

Silicon carbide (SiC) is a promising material for applications in harsh environments. Standard silicon (Si) microelectromechanical systems (MEMS) are limited in operating temperature to temperatures below 130°C for electronic devices and below 600°C for mechanical devices. Due to its large bandgap SiC enables MEMS with significantly higher operating temperatures. Furthermore, SiC exhibits high chemical stability and thermal conductivity. Young's modulus and residual stress are important mechanical properties for the design of sophisticated SiCbased MEMS devices. In particular, residual stresses are strongly dependent on the deposition conditions. Literature values for Young's modulus range from 100 to 400 GPa, and residual stresses range from 98 to 486 MPa. In this paper we present our work on investigating Young's modulus and residual stress of SiC films deposited on single crystal bulk silicon using bulge testing. This method is based on measurement of pressure-dependent membrane deflection. Polycrystalline as well as single crystal cubic silicon carbide samples are studied. For the samples tested, average Young's modulus and residual stress measured are 417 GPa and 89 MPa for polycrystalline samples. For single crystal samples, the according values are 388 GPa and 217 MPa. These results compare well with literature values.

Size effect of the silicon carbide Young's modulus

“…E 0 for (111) was fitted to 415 GPa which is slightly lower than for (100), mainly caused by the high scattering of the literature data. Usually (111) oriented 3C‐SiC exhibits a higher Young's modulus than (100) oriented . The surface elasticity was fitted to C S = 1674 N m −1 .…”

Coatable strain sensors for nonplanar surfaces

“…Fig. 1e 2,26,41–55 delves into the operational challenges faced by stretchable strain sensors, especially when dealing with surfaces that exhibit not only high roughness, but also diverse Young's modulus values. While most sensors are adequate on smooth surfaces with roughness below 1 micrometer, their performance often falters on more ‘complex’ surfaces.…”

Design Optimization and Mechanical Properties of SiC Particle Reinforced Ti-Based Metallic Glass Matrix Composite

“…Figure 2e-g shows the FEM analysis results for the equivalent plastic strain, where the low strain zone is essentially located within the SiC particles. This can be attributed to the fact that the Young's modulus of a SiC particle (~400-550 GPa [57,58,61,62]) is about six times that of MG matrix alloy (~100 GPa [56,63,64]), resulting in the smaller deformation of SiC particles under the same stress-bearing conditions. However, as V f increases, the low strain region in the SiC particles gradually decreases, which can be attributed to the increasing effect of SiC V f on the maximum stress under the same deformation amount, as shown in Figure 2a-d.…”