A method for controlling residual film stress in LPCVD polysilicon films for surface micromachined MEMS

2004 ◽  
Author(s):  
J. Woloszyn
Keyword(s):  
Film Stress ◽  
Residual Film ◽  
Polysilicon Films

scholarly journals Induced Crystallization In CW Laser-Irradiated Sol-Gel Deposited Titania Films

1993 ◽  
Vol 321 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Laser Fluence ◽  
Sol Gel ◽  
Film Stress ◽  
Amorphous Films ◽  
Time Resolved ◽  
Cw Laser ◽  
Residual Film ◽  
Titania Films ◽  
Induced Crystallization ◽  
Nanograin Size

AbstractIsothermal annealing of amorphous TiO2 films deposited from acidic sol-gel precursor solutions results in film densification and concomitant increase in refractive index. Subsequent heating above 300°C leads to irreversible transformation to an anatase crystalline phase. Similar phenomena occur when such amorphous films are subjected to focused cw laser irradiation. Controlled variations in laser fluence are used to density or crystallize selected regions of the film. Low fluence conditioning leads to the evolution of a subtle nanograin-size morphology, evident in AFM images, which appears to retard subsequent film crystallization when such regions are subjected to higher laser fluence. Time-resolved Raman spectroscopy has been used to characterize irradiated regions in order to follow the crystallization kinetics, assess phase homogeneity, and evaluate accompanying changes in residual film stress.

scholarly journals Induced Crystallization in CW Laser-Irradiated Sol-Gel Deposited Titania Films

1993 ◽  
Vol 316 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Laser Fluence ◽  
Sol Gel ◽  
Film Stress ◽  
Amorphous Films ◽  
Time Resolved ◽  
Cw Laser ◽  
Residual Film ◽  
Titania Films ◽  
Induced Crystallization ◽  
Nanograin Size

ABSTRACTIsothermal annealing of amorphous TiO2 films deposited from acidic sol-gel precursor solutions results in film densification and concomitant increase in refractive index. Subsequent heating above 300°C leads to irreversible transformation to an anatase crystalline phase. Similar phenomena occur when such amorphous films are subjected to focused cw laser irradiation. Controlled variations in laser fluence are used to density or crystallize selected regions of the film. Low fluence conditioning leads to the evolution of a subtle nanograin-size morphology, evident in AFM images, which appears to retard subsequent film crystallization when such regions are subjected to higher laser fluence. Time-resolved Raman spectroscopy has been used to characterize irradiated regions in order to follow the crystallization kinetics, assess phase homogeneity, and evaluate accompanying changes in residual film stress.

Characterization of Stress and Texture in Rtcvd Poly-Si Layers by X-Ray Diffraction

1991 ◽  
Vol 239 ◽  
Author(s):  
István Bársony ◽  
Jos G.E. Klappe ◽  
Tom W. Ryan
Keyword(s):  
Deposition Temperature ◽  
Polycrystalline Silicon ◽  
Columnar Structure ◽  
Film Stress ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Film ◽  
Post Deposition

ABSTRACTThe properties of polycrystalline silicon layers deposited by RTCVD have been studied by texture, stress and electrical analyse. The intrinsic layers intended for applications in integrated IC processing are very much textured with the preferred orientation depending on deposition temperature and atmosphere. Very low residual film stress in the order of 10 dyn/cm2 was detected, and a transition from compressive to tensile stress with increasing deposition temperature around 800°C was observed. This was associated with the development of the columnar structure by the (110) orientation becoming dominant at the expense of the (100) texture. Also the effect of post-deposition anneal ambience on the grain structure has been studied. Grain size and grain-boundary trapping in after doped layers have been evaluated in P-implanted RTA activated layers.

AlN Actuator for Tunable RFMEMS Capacitor

2011 ◽  
Vol 254 ◽  
pp. 29-33 ◽  
Author(s):  
Sanchitha Fernando ◽  
Tang Min ◽  
Lynn Khine ◽  
Rahul Agarwal ◽  
Kia Hian Lau ◽  
...  
Keyword(s):  
Film Stress ◽  
The Novel ◽  
Constant Independent ◽  
Mems Switches ◽  
Tunable Capacitor ◽  
Movable Electrode ◽  
Residual Film ◽  
Fixed Electrode ◽  
Actuator Design ◽  
Piezoelectric Devices

This paper presents a novel piezoelectric actuator design that achieves low curling due to residual film stress. The proposed actuator maintains the gap between the movable electrode and the fixed electrode nearly constant independent of the residual stress level, improving the reproducibility and reliability of piezoelectric devices. At 20V excitation, the actuator deflects more than 5 µm. The design also achieves a capacitor electrode around 6% of the total actuator area, which is 2.5 times greater than other reported designs. This paper demonstrates the novel actuator in a tunable capacitor, but the actuator may be used in many other applications, such as MEMS switches and micro-mirrors.

Mechanical and Piezoresistive Properties of Graphite-Filled Polyimide Thin Films

1992 ◽  
Vol 276 ◽  
Author(s):  
A. Bruno Frazier ◽  
M. R. Khan ◽  
Mark G. Allen
Keyword(s):  
Thin Films ◽  
Film Stress ◽  
Polyimide Films ◽  
Film Properties ◽  
Piezoresistive Effect ◽  
Strong Function ◽  
Graphite Particles ◽  
Microelectronic Fabrication ◽  
Residual Film

ABSTRACTThe piezoresistive effect of materials is used as the basis for many types of microsensors. Polyimide, a material widely used in microelectronic fabrication, may be made to exhibit this effect by addition of small graphite particles to form a composite material. Polyimide / graphite based piezoresistive films have the advantage of being spin-castable, plasma-processable, highly chemically resistant, and thermally stable up to 400 °C in nitrogen atmospheres. In this work, piezoresistive polyimide films are formed by addition of various amounts (loadings) of graphite particles one micron in diameter or less to DuPont PI-2555 polyimide. Thin films of these materials are spin-cast on silicon wafers, and an in-situ load-deflection measurement technique is used to evaluate the following film properties: piezoresistive coefficient as a function of both strain and graphite loading; Young's modulus as a function of graphite loading; and residual film stress as a function of graphite loading. The observed piezoresistive coefficient is a strong function of graphite loading, with good piezoresistive properties exhibited in the loading range of 15–25 wt% graphite.

Processing and morphology of permeable polycrystalline silicon thin films

2002 ◽  
Vol 17 (9) ◽  
pp. 2235-2242 ◽  
Author(s):  
G. G. Dougherty ◽  
A. A. Pisano ◽  
T. Sands
Keyword(s):  
Thin Films ◽  
Polycrystalline Silicon ◽  
Film Growth ◽  
Film Stress ◽  
Silicon Thin Films ◽  
Residual Film ◽  
Simple Kinetic Model ◽  
Free Films ◽  
The Right ◽  
The Relationship

It is known that thin films of polycrystalline silicon, deposited under the right conditions, can be permeable to HF-based etching solutions. While these films offer unique capabilities for microfabrication, both the poor reproducibility of the permeable film properties and the lack of a detailed physical understanding of the material have limited their application. This work provides a methodical study of the relationship between process, microstructure, and properties of permeable polycrystalline silicon thin films. It is shown that the permeability is a result of small pores, on the order of 10 nm, between the 100–200-nm hemispherical grains characteristic of the permeable film morphology. This morphology occurs only in nearly stress-free films grown in a narrow temperature range corresponding to the transition between tensile and compressive film growth regimes. This result strongly suggests that the monitoring of residual film stress can provide the process control needed to reliably produce permeable films. A simple kinetic model is proposed to explain the evolution of the morphology of the permeable films.

Mechanical Properties of Carbon Films for Thin Film Disks

1990 ◽  
Vol 188 ◽  
Author(s):  
Richard L. White ◽  
Mary F. Doerner ◽  
George W. Walker
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Argon Plasma ◽  
Carbon Films ◽  
Film Stress ◽  
Film Hardness ◽  
Residual Film ◽  
Frictional Performance ◽  
Curvature Measurements ◽  
Relationship Of

ABSTRACTCarbon overcoat films are used extensively in thin film disk applications to provide wear resistance. A nano-indentation technique and wafer curvature measurements have been used to study the mechanical properties of carbon films sputtered under various processing conditions. Specifically, the effects of substrate/target spacing, power, pressure, and substrate bias have been studied for films sputtered in an argon plasma. The relationship of these properties to contact start-stop performance of hydrocarbon lubricated disks is further described. The frictional performance during the test can be related to film hardness, while the durability can be affected by the residual film stress.

Mitigation of residual film stress deformation in multilayer microelectromechanical systems cantilever devices

2003 ◽  
Vol 21 (6) ◽  
pp. 2482 ◽  
Author(s):  
Jeffrey S. Pulskamp ◽  
Alma Wickenden ◽  
Ronald Polcawich ◽  
Brett Piekarski ◽  
Madan Dubey ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Film Stress ◽  
Residual Film ◽  
Stress Deformation

Stress in evaporated films used in GaAs processing

1991 ◽  
Vol 6 (3) ◽  
pp. 548-552 ◽  
Author(s):  
W.A. Strifler ◽  
C.W. Bates
Keyword(s):  
Thin Films ◽  
Practical Method ◽  
Optical Microscope ◽  
Metal Films ◽  
Film Stress ◽  
Cantilever Beams ◽  
Vertical Deflection ◽  
Thermal Component ◽  
Residual Film ◽  
Micro Cantilever

A simple and practical method is described for determining the residual stress in vapor deposited thin films that are less than 1000 Å in thickness. The method relies on the evaporation of thin films onto prefabricated micro-cantilever beams of SiO2. The vertical deflection at the end of the beam is measured using an optical microscope to determine the average film stress with a resolution of 25 MPa. Calculations show that the vapor deposition of metal films onto these beams does not induce significant heating, so the thermal component of residual film stress is minimal. The micro-cantilever technique is used to measure the film stress in 500 Å films of Al, Ti, Pt, Au, Ni, and Ge. These measured values are compared to similar measurements reported in the literature.

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