scholarly journals Nanomechanical spectroscopy of ultrathin silicon nitride suspended membranes

2021 ◽  
Vol 93 (5) ◽  
pp. 50301
Author(s):  
Sanket S. Jugade ◽  
Anuj Aggarwal ◽  
Akshay K. Naik
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Silicon Nitride ◽  
Chemical Vapor ◽  
Intrinsic Stress ◽  
Nanomechanical Resonator ◽  
Pressure Chemical ◽  
Suspended Membrane ◽  
Nano Electromechanical System

Mechanical properties of a nanomechanical resonator significantly impact the performance of a resonant Nano-electromechanical system (NEMS) device. We study the mechanical properties of suspended membranes fabricated out of low-pressure chemical vapor deposited silicon nitride thin films. We fabricated doubly-clamped membranes of silicon nitride with thickness less than 50 nm and length varying from 5 to 60 μm. The elastic modulus and stress in the suspended membranes were measured using Atomic Force Microscope (AFM)-based nanomechanical spectroscopy. The elastic moduli of the suspended membranes are significantly higher than those of corresponding on-substrate thin films. We observed a reduction in net stress after the fabrication of suspended membrane, which is explained by estimating the thermal stress and intrinsic stress. We also use a mathematical model to study the stress and thickness-dependent elastic modulus of the ultrathin membranes. Lastly, we study the capillary force-gradient between the SiNx suspended membrane-Si substrate that could collapse the suspended membrane.

Microbridge Testing of Thin Films Under Small Deformation

1999 ◽  
Vol 594 ◽  
Author(s):  
T. Y. Zhang ◽  
Y. J. Su ◽  
C. F. Qian ◽  
M. H. Zhao ◽  
L. Q. Chen
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Small Deformation ◽  
Nitride Film ◽  
Silicon Nitride Film ◽  
Pressure Chemical

AbstractThe present work proposes a novel microbridge testing method to simultaneously evaluate the Young's modulus, residual stress of thin films under small deformation. Theoretic analysis and finite element calculation are conducted on microbridge deformation to provide a closed formula of deflection versus load, considering both substrate deformation and residual stress in the film. Silicon nitride films fabricated by low pressure chemical vapor deposition on silicon substrates are tested to demonstrate the proposed method. The results show that the Young's modulus and residual stress for the annealed silicon nitride film are respectively 202 GPa and 334.9 MPa.

scholarly journals Material Structure and Mechanical Properties of Silicon Nitride and Silicon Oxynitride Thin Films Deposited by Plasma Enhanced Chemical Vapor Deposition

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Zhenghao Gan ◽  
Changzheng Wang ◽  
Zhong Chen
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Silicon Oxynitride ◽  
Flow Rates ◽  
Silicon Nitride Films

Silicon nitride and silicon oxynitride thin films are widely used in microelectronic fabrication and microelectromechanical systems (MEMS). Their mechanical properties are important for MEMS structures; however, these properties are rarely reported, particularly the fracture toughness of these films. In this study, silicon nitride and silicon oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) under different silane flow rates. The silicon nitride films consisted of mixed amorphous and crystalline Si3N4 phases under the range of silane flow rates investigated in the current study, while the crystallinity increased with silane flow rate in the silicon oxynitride films. The Young’s modulus and hardness of silicon nitride films decreased with increasing silane flow rate. However, for silicon oxynitride films, Young’s modulus decreased slightly with increasing silane flow rate, and the hardness increased considerably due to the formation of a crystalline silicon nitride phase at the high flow rate. Overall, the hardness, Young modulus, and fracture toughness of the silicon nitride films were greater than the ones of silicon oxynitride films, and the main reason lies with the phase composition: the SiNx films were composed of a crystalline Si3N4 phase, while the SiOxNy films were dominated by amorphous Si–O phases. Based on the overall mechanical properties, PECVD silicon nitride films are preferred for structural applications in MEMS devices.

scholarly journals Synthesis and Characterization of LPCVD Polysilicon and Silicon Nitride Thin Films for MEMS Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
N. Sharma ◽  
M. Hooda ◽  
S. K. Sharma
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Silicon Nitride ◽  
Chemical Vapor ◽  
Process Conditions ◽  
Mems Devices ◽  
Material Deposition ◽  
Wide Range ◽  
Pressure Chemical ◽  
Annealing Effects

Inherent residual stresses during material deposition can have profound effects on the functionality and reliability of fabricated MEMS devices. Residual stress often causes device failure due to curling, buckling, or fracture. Typically, the material properties of thin films used in surface micromachining are not very well controlled during deposition. The residual stress, for example, tends to vary significantly for different deposition conditions; experiments were carried out to study the polysilicon and silicon nitride deposited by Low Pressure Chemical Vapor Deposition (LPCVD) method at wide range of process conditions. High temperature annealing effects on stress in case polysilicon are also reported. The reduced residual stress levels can significantly improve device performance, reliability, and yield as MEMS devices become smaller.

Study of SiC’s Mechanical Property Variance Caused by Film Thickness

2015 ◽  
Vol 645-646 ◽  
pp. 400-404
Author(s):  
Zong Lei Jiao ◽  
Jian Zhu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Chemical Vapor Deposition ◽  
Elastic Modulus ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Indentation Load

The mechanical properties of SiC thin films deposited by chemical vapor deposition process on silicon substrate are studied using nanoindentation techniques. The SiC thin films are of three different thicknesses: 1.6μm、4.5μm、9μm. In this study, nanoindentation method is preferred due to its reliability and accuracy on determining mechanical properties from indentation load-displacement data. The mechanical properties of elastic modulus and hardness are characterized. 1.6μm SiC thin film has the following values: E=345.73Gpa, H=33.71Gpa; 4.5μm SiC thin film has the following values: E=170.18Gpa, H=10.33Gpa; 9μm SiC thin film: E=167.96Gpa, H=9.48Gpa

Transient Thermoreflectance Measurement of Thermal Conductivity of Nanoscale Silicon Nitride Thin Films

2007 ◽  
Author(s):  
SuYuan Bai ◽  
ZhenAn Tang ◽  
ZhengXing Huang ◽  
JiaQi Wang
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Silicon Nitride ◽  
Bulk Material ◽  
Chemical Vapor ◽  
Interfacial Thermal Resistance ◽  
Silicon Nitride Films ◽  
Pressure Chemical ◽  
Material Values ◽  
Thermal Conductivities

The present work measured the thermal conductivities of the silicon nitride films prepared by lower pressure chemical vapor deposition (LPCVD) with thicknesses ranging from 100 nm to 200 nm. The measurements were made at room temperature using the transient photothermal reflectance technique, which is a non-contacting and non-destructive optical approach. The data measured were fitted by genetic algorithm to get the thermal conductivity of thin films and interfacial thermal resistance simultaneously. The results show that thermal conductivities of these films are lower than corresponding bulk material values. The interfacial thermal resistances are in the order of 10−8 m2K/W. It cannot be neglected for the very thin films. Some comparison and analysis for the results were discussed.

On the Role of the Underlying Microstructure on the Mechanical Properties of Microelectromechanical Systems (MEMS) Materials

2000 ◽  
Vol 657 ◽  
Author(s):  
G. F. Dirras ◽  
G. Coles ◽  
A. J. Wagner ◽  
S. Carlo ◽  
C. Newman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Mechanical Properties ◽  
Microelectromechanical Systems ◽  
Chemical Vapor ◽  
Xrd Analysis ◽  
Transmission Electron ◽  
Columnar Grains ◽  
Pressure Chemical ◽  
20 Nm

ABSTRACTThe microstructure of Low Pressure Chemical Vapor Deposition (LPCVD) Polycrystalline silicon (Polysilicon) thin films was investigated by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and Auger electron spectroscopy (AES). SEM characterization of tensile tested samples showed a brittle like-rupture, along with grooves located at the surface sides of the sample. TEM investigations of as-deposited samples showed equiaxed or fully columnar grains bridging from the bottom to the top of the films. A microstructural coarsening was observed with annealing. In the as-deposited state, the films exhibited a {110} texture as showed by the XRD analysis. The films' top and bottom surfaces were observed to be smooth with a roughness (standard deviation) of about 11nm and 20 nm respectively. A chemical analysis of the thin films showed the presence of carbon and oxygen impurities on the surface and oxygen through the sample as observed in the depth profile. The hypothetical influence of these findings is subsequently discussed in relation to the measured mechanical properties.

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