Mechanical characterization of polysilicon through on-chip tensile tests

Two new types of on-chip tests have been designed in order to evaluate the elastic Young modulus and the fracture strength of polysilicon used in microelectromechanical systems (MEMS). The former is a pure tension test, while the latter is a single-edge-notched tension test. The actuation in both tests is obtained by means of an ad hoc designed layout of parallel plates capacitors applying sufficiently high forces to reach significant strains in the tensile specimens and complete failure of the notched specimens. The pure tension tests on 20 specimens showed a low dispersion and gave a Young modulus for the polysilicon of 143 GPa. A total of 92 notched specimens were tested up to failure. The experimental results, supported by finite-element simulations, gave a value of the maximum stress for the notched specimens in the range 4144-4568 MPa.

[1]  Robert O. Ritchie,et al.  High-cycle Fatigue and Durability of Polycrystalline Silicon Thin ®lms in Ambient Air , 2022 .

[2]  M. Madou.  Fundamentals of microfabrication , 1997 .

[3]  Stefan Johansson,et al.  In situ tensile strength measurement and Weibull analysis of thick film and thin film micromachined polysilicon structures , 1997 .

[4]  W. Weibull.  A Statistical Distribution Function of Wide Applicability , 1951 .

[5]  S.E. Lyshevski,et al.  MEMS and NEMS - systems, devices, and structures , 2004, IEEE Electrical Insulation Magazine.

[6]  Ioannis Chasiotis,et al.  The mechanical strength of polysilicon films: Part 2. Size effects associated with elliptical and circular perforations , 2003 .

[7]  R. L. Edwards,et al.  Tensile testing of polysilicon , 1999 .

[8]  Ioannis Chasiotis,et al.  The mechanical strength of polysilicon films : Part 1. The influence of fabrication governed surface conditions , 2003 .

[9]  Mitsuhiro Shikida,et al.  Tensile-mode fatigue testing of silicon films as structural materials for MEMS , 2001 .

[10]  Sergey Edward Lyshevski,et al.  Mems and Nems , 2018 .

[11]  C. Kim,et al.  Microscale material testing of single crystalline silicon: process effects on surface morphology and tensile strength , 2000 .

[12]  William N. Sharpe,et al.  Fracture strength of polysilicon at stress concentrations , 2003 .

[13]  Robert L. Mullen,et al.  Fracture toughness of polysilicon MEMS devices , 2000 .

[14]  Surface micromachined ring test structures to determine mechanical properties of compressive thin films , 2001 .

[15]  Effects of monolithic silicon postulated as an isotropic material on design of microstructures , 2000 .

[16]  William C. Tang,et al.  Electrostatic Comb Drive Levitation And Control Method , 1992 .

[17]  W. Knauss,et al.  A new microtensile tester for the study of MEMS materials with the aid of atomic force microscopy , 2002 .

[18]  Mechanical characterization of epitaxial polysilicon in MEMS , 2003 .

[19]  S. Senturia,et al.  M-TEST: A test chip for MEMS material property measurement using electrostatically actuated test structures , 1997 .

[20]  Patrick J. French,et al.  Polysilicon: a versatile material for microsystems , 2002 .

[21]  Wensyang Hsu,et al.  A microstructure for in situ determination of residual strain , 1999 .

[22]  R. L. Edwards,et al.  Measurements of Young's modulus, Poisson's ratio, and tensile strength of polysilicon , 1997, Proceedings IEEE The Tenth Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots.