The Effects of Texture and Doping on The Young's Modulus of Polysilicon

1998 ◽  
Vol 518 ◽  
Author(s):  
Sangwoo Lee ◽  
Changho Cho ◽  
Jongpal Kim ◽  
Sangjun Park ◽  
Sangwoo Yi ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Young's Modulus ◽  
Chemical Deposition ◽  
Phosphorus Doping ◽  
Resonant Frequencies ◽  
Pressure Chemical ◽  
Polysilicon Films ◽  
Deposition Processes ◽  
Post Deposition

AbstractPolysilicon films deposited by low pressure chemical deposition (LPCVD) are the most widely used structural material for microelectromechanical systems (MEMS). However, the structural properties of LPCVD polysilicon films are known to vary significantly, depending on deposition conditions as well as post-deposition processes. This paper investigates the effects of phosphorus doping and texture on Young's modulus of polysilicon films. Polysilicon films are depostied at 585°C, 605"C, and 625°C to a thickness of 2µm. Specimens with varying phosphorus doping levels are prepared by diffusion doping at various temperatures and times using both POCl3 and phosphorsilicate glass (PSG) as the source. Texture is measured using an X-ray diffractometer. Young's modulus is calculated by taking the average of the values calculated from the resonant frequencies of four-different size lateral resonators. Our results show that Young's modulus of diffusion doped polysilicon films decreases with increasing doping concentration, and increases with increasing <111> texture.

The effects of post-deposition processes on polysilicon Young's modulus

1998 ◽  
Vol 8 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sangwoo Lee ◽  
Changho Cho ◽  
Jongpal Kim ◽  
Sangjun Park ◽  
Sangwoo Yi ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Deposition Processes ◽  
Post Deposition

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.

Effects of Aluminum Incorporation on the Young’s Modulus of 3C-SiC Epilayers

2019 ◽  
Vol 963 ◽  
pp. 305-308
Author(s):  
Jaweb Ben Messaoud ◽  
Jean François Michaud ◽  
Marcin Zielinski ◽  
Daniel Alquier
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Young’S Modulus ◽  
Stress Level ◽  
Microelectromechanical Systems ◽  
Young's Modulus ◽  
Al Doping ◽  
Noticeable Reduction

The silicon carbide cubic polytype (3C-SiC) is a material of choice to fabricate microelectromechanical systems. However, the mechanical properties of 3C-SiC-based devices are severely linked to the stress of the involved 3C-SiC material. Moreover, the stress level can hamper completing microsystems. As a consequence, in this study, we considered the influence of aluminum (Al) doping towards the mechanical properties of 3C-SiC epilayers and demonstrated a noticeable reduction of the Young’s modulus with a high Al incorporation.

A Nanoindentation-Based Microbridge Testing Method for Mechanical Characterization of Thin Films for MEMS Applications

2005 ◽  
Author(s):  
Zhiqiang Cao ◽  
Tong-Yi Zhang ◽  
Xin Zhang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Mechanical Characterization ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Testing Method ◽  
Chemical Vapor Deposited

Plasma-enhanced chemical vapor deposited (PECVD) silane-based oxides (SiOx) have been widely used in both microelectronics and MEMS (MicroElectroMechanical Systems) to form electrical and/or mechanical components. In this paper, a novel nanoindentation-based microbridge testing method is developed to measure both the residual stresses and Young’s modulus of PECVD SiOx films on silicon wafers. Theoretically, we considered both the substrate deformation and residual stress in the thin film and derived a closed formula of deflection versus load. The formula fitted the experimental curves almost perfectly, from which the residual stresses and Young’s modulus of the film were determined. Experimentally, freestanding microbridges made of PECVD SiOx films were fabricated using the silicon undercut bulk micromachining technique. The results showed that the as-deposited PECVD SiOx films had a residual stress of −155±17 MPa and a Young’s modulus of 74.8±3.3 GPa.

scholarly journals Investigation of the Young’s Modulus and the Residual Stress of 4H-SiC Circular Membranes on 4H-SiC Substrates

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 801 ◽  
Author(s):  
Jaweb Ben Messaoud ◽  
Jean-François Michaud ◽  
Dominique Certon ◽  
Massimo Camarda ◽  
Nicolò Piluso ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Film Growth ◽  
Electrochemical Etching ◽  
Young's Modulus ◽  
Fabrication Process ◽  
Bulge Test ◽  
Residual Strains

The stress state is a crucial parameter for the design of innovative microelectromechanical systems based on silicon carbide (SiC) material. Hence, mechanical properties of such structures highly depend on the fabrication process. Despite significant progresses in thin-film growth and fabrication process, monitoring the strain of the suspended SiC thin-films is still challenging. However, 3C-SiC membranes on silicon (Si) substrates have been demonstrated, but due to the low quality of the SiC/Si heteroepitaxy, high levels of residual strains were always observed. In order to achieve promising self-standing films with low residual stress, an alternative micromachining technique based on electrochemical etching of high quality homoepitaxy 4H-SiC layers was evaluated. This work is dedicated to the determination of their mechanical properties and more specifically, to the characterization of a 4H-SiC freestanding film with a circular shape. An inverse problem method was implemented, where experimental results obtained from bulge test are fitted with theoretical static load-deflection curves of the stressed membrane. To assess data validity, the dynamic behavior of the membrane was also investigated: Experimentally, by means of laser Doppler vibrometry (LDV) and theoretically, by means of finite element computations. The two methods provided very similar results since one obtained a Young’s modulus of 410 GPa and a residual stress value of 41 MPa from bulge test against 400 GPa and 30 MPa for the LDV analysis. The determined Young’s modulus is in good agreement with literature values. Moreover, residual stress values demonstrate that the fabrication of low-stressed SiC films is achievable thanks to the micromachining process developed.

Nanoindentation Measurements on Low-k Porous Silica Thin Films Spin Coated on Silicon Substrates

2003 ◽  
Vol 125 (4) ◽  
pp. 361-367 ◽  
Author(s):  
Xiaoqin Huang ◽  
Assimina A. Pelegri
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Young's Modulus ◽  
Porous Silica ◽  
Silicon Substrates ◽  
Silica Thin Films ◽  
Low K

MEMS (MicroElectroMechanical Systems) are composed of thin films and composite nanomaterials. Although the mechanical properties of their constituent materials play an important role in controlling their quality, reliability, and lifetime, they are often found to be different from their bulk counterparts. In this paper, low-k porous silica thin films spin coated on silicon substrates are studied. The roughness of spin-on coated porous silica films is analyzed with in-situ imaging and their mechanical properties are determined using nanoindentation. A Berkovich type nanoindenter, of a 142.3 deg total included angle, is used and continuous measurements of force and displacements are acquired. It is shown, that the measured results of hardness and Young’s modulus of these films depend on penetration depth. Furthermore, the film’s mechanical properties are influenced by the properties of the substrate, and the reproduction of the force versus displacement curves depends on the quality of the thin film. The hardness of the studied low-k spin coated silica thin film is measured as 0.35∼0.41 GPa and the Young’s modulus is determined as 2.74∼2.94 GPa.

Applications of Polysilicon Films in Microsensors and Microactuators

1987 ◽  
Vol 106 ◽  
Author(s):  
Roger T. Howe
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Young’S Modulus ◽  
Ultimate Strength ◽  
Residual Strain ◽  
Friction And Wear ◽  
Young's Modulus ◽  
Strain Gauges ◽  
Polysilicon Films ◽  
Micromechanical Structures

ABSTRACTThis paper reviews the applications of polysilicon in microsensor technology and in the emerging field of microfabricated actuators. Polysilicon is an attractive material for thin-film strain gauges, and is also used to fabricate micromechanical structures. The need for better understanding of the non-electrical properties of polysilicon, such as Young's modulus, residual strain, ultimate strength, friction, and wear, is emphasized.

Simulation of capacitive pressure sensor based on microelectromechanical systems technology

2017 ◽  
Vol 232 (9) ◽  
pp. 1538-1546
Author(s):  
Masoud Baghelani ◽  
Ahmad Hosseini-Sianaki ◽  
Zeinab Behzadi ◽  
Arash Mirabdolah Lavasani
Keyword(s):  
Young’S Modulus ◽  
Pressure Sensor ◽  
Microelectromechanical Systems ◽  
Young's Modulus ◽  
High Sensitivity ◽  
Capacitive Pressure Sensor ◽  
Suspension Spring ◽  
Length Increase ◽  
Modulus Reduction ◽  
Very High

This paper proposes a very high sensitivity pressure sensor with a novel technique for temperature compensation. The proposed technique employs a geometrical method for self-compensation of Young’s modulus reduction due to temperature increase, where a stronger spring with much larger length and width is anchored. According to the connection of the suspension spring to the larger spring, in higher temperatures, the large spring experiences more length increase, which in turn increases the stiffness of the suspension spring and, consequently, could compensates the Young’s modulus reduction. Simulation results verify that the temperature variation related error in the compensated sensor is less than 0.66% of full-scale under 260 ℃ of temperature range, which shows considerable improvement in comparison with literature. The total consumed area is about 0.033 mm2 with the sensitivity of 290 × 10−6 K−1.

Property Modification of 3C-SiC MEMS on Ge-Modified Si(100) Substrates

2010 ◽  
Vol 645-648 ◽  
pp. 861-864 ◽  
Author(s):  
Florentina Niebelschütz ◽  
Wei Hong Zhao ◽  
Klemens Brueckner ◽  
Katja Tonisch ◽  
Matthias Linß ◽  
...  
Keyword(s):  
Residual Stress ◽  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Young's Modulus ◽  
Growth Conditions ◽  
Quality Factors ◽  
Growth Changes ◽  
Property Modification ◽  
Good Agreement

The manipulation of nucleation and growth conditions with Ge deposition prior to the carbonization and epitaxial growth changes the residual stress and the material quality of 3C-SiC(100)-layers grown on Si(100). This enables the modification of quality factor and resonant frequency of microelectromechanical systems (MEMS) based on 3C-SiC-layers. Measured resonant frequencies and quality factors of the magnetomotively actuated MEMS exhibit a dependence on the Ge amount at the interface of the Si/SiC heterostructure. This offers a degree of freedom to adjust the MEMS properties within a certain range to the requirements necessary for specific applications. The observed dependencies of the Young’s modulus are in good agreement with the trends of residual stress and Young’s modulus, which were determined on as grown 3C-SiC(100):Ge samples by fourier transform infrared (FTIR) spectroscopy and nanoindentation.

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