TY - JOUR
T1 - Application of MEMS force sensors for in situ mechanical characterization of nano-scale thin films in SEM and TEM
AU - Haque, M. A.
AU - Saif, M. T.A.
N1 - Funding Information:
The research was funded by NSF grant ECS 97-34368. The test chips were fabricated in the MEMS laboratory of the Department of Mechanical and Industrial Engineering, University of Illinois at Urbana Champaign. The experiments were conducted in the Environmental SEM in the Imaging Technology Group (ITG) laboratory in Beckman Institute at the University of Illinois at Urbana Champaign. The TEM image ( Fig. 6 ) was taken by ITG as well. We acknowledge Ian Robertson for his assistance in showing the compatibility of the test chip with a TEM straining stage.
PY - 2002/4/1
Y1 - 2002/4/1
N2 - We present a novel tensile testing technique utilizing MEMS force sensors for in situ mechanical characterization of sub-micron scale freestanding thin films in SEM and TEM. Microfabrication techniques are used to cofabricate the thin film specimens with force sensors to produce the following unique features: (1) small setup size to fit in SEM and TEM for in situ experiments, (2) ability to measure tensile pre-stress in specimen, (3) alignment between specimen and applied loading axes with lithographic precision, (4) no extra gripping mechanism required, and (5) ability to measure creep strain in the material. The technique allows single or multilayers of materials that can be deposited/grown on silicon substrate to be tested. We demonstrate the technique by testing a 100 nm thick, 8.8 μm wide and 275 μm long freestanding aluminum specimen (average grain size about 50 nm) in situ inside an environmental SEM chamber, and present another setup for similar experiment in TEM. Experimental results strongly suggest that at this size scale: (1) elastic modulus does not change, (2) size effects on yield strength are pronounced (63 times the bulk pure aluminum yield stress), and (3) permanent strain hardening effect are absent.
AB - We present a novel tensile testing technique utilizing MEMS force sensors for in situ mechanical characterization of sub-micron scale freestanding thin films in SEM and TEM. Microfabrication techniques are used to cofabricate the thin film specimens with force sensors to produce the following unique features: (1) small setup size to fit in SEM and TEM for in situ experiments, (2) ability to measure tensile pre-stress in specimen, (3) alignment between specimen and applied loading axes with lithographic precision, (4) no extra gripping mechanism required, and (5) ability to measure creep strain in the material. The technique allows single or multilayers of materials that can be deposited/grown on silicon substrate to be tested. We demonstrate the technique by testing a 100 nm thick, 8.8 μm wide and 275 μm long freestanding aluminum specimen (average grain size about 50 nm) in situ inside an environmental SEM chamber, and present another setup for similar experiment in TEM. Experimental results strongly suggest that at this size scale: (1) elastic modulus does not change, (2) size effects on yield strength are pronounced (63 times the bulk pure aluminum yield stress), and (3) permanent strain hardening effect are absent.
KW - MEMS force sensor
KW - Tensile testing
KW - Thin film properties
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U2 - 10.1016/S0924-4247(01)00861-5
DO - 10.1016/S0924-4247(01)00861-5
M3 - Conference article
AN - SCOPUS:0036544276
SN - 0924-4247
VL - 97-98
SP - 239
EP - 245
JO - Sensors and Actuators, A: Physical
JF - Sensors and Actuators, A: Physical
T2 - Transducers'01 Eurosensors XV
Y2 - 10 June 2001 through 14 June 2001
ER -