The Effect of Inorganic Thin Film Material Processing and Properties on Stress in Silicon Piezoresistive Pressure Sensors

1996 ◽  
Vol 444 ◽  
Author(s):  
G. Bitko ◽  
A. C. McNeil ◽  
D. J. Monk

AbstractSilicon bulk micromachined piezoresistive pressure sensors are sensitive to stresses caused by the application of inorganic thin films typically used for passivation purposes, and the change in stress that is caused by temperature changes in the operating environment of the sensor. Stress behavior over temperature is characterized for both thermal oxides grown on silicon at thicknesses from 0.18 μm to 0.36 μm, and PECVD silicon nitride films at thicknesses from 0.40 μm to 0.80 μn. Electrical parametric behavior is characterized for typical piezoresistive pressure sensors with these thin films deposited and patterned in several proposed passivation schemes. A finite element analysis is performed to predict how device parameters vary as a function of thin film patterning and properties. Correlations are drawn between model predictions, independent thin film behavior, and device performance.

2021 ◽  
Vol 317 ◽  
pp. 477-482
Author(s):  
Aris Doyan ◽  
Susilawati ◽  
Muhammad Taufik ◽  
Syamsul Hakim ◽  
Lalu Muliyadi

Tin oxide (SnO2) thin film is a form of modification of semiconductor material in nanosize. The thin film study aims to analyze the effect of triple doping (Aluminum, Indium, and Fluorine) on the optical properties of SnO2: (Al + In + F) thin films. Aluminum, Indium, and Fluorine as doping SnO2 with a mass percentage of 0, 5, 10, 15, 20, and 25% of the total thin-film material. The addition of Al, In, and F doping causes the thin film to change optical properties, namely the transmittance and absorbance values ​​changing. The transmittance value is 67.50, 73.00, 82.30, 87.30, 94.6, and 99.80 which is at a wavelength of 350 nm for the lowest to the highest doping percentage, respectively. The absorbance value increased with increasing doping percentage at 300 nm wavelength of 0.52, 0.76, 0.97, 1.05, 1.23, and 1.29 for 0, 5, 10, 15, 20, and 25% doping percentages, respectively. The absorbance value is then used to find the gap energy of the SnO2: (Al + In + F) thin film of the lowest doping percentage to the highest level i.e. 3.60, 3.55, 3.51, 3.47, 3.42, and 3.41 eV. Thin-film activation energy also decreased with values of 2.27, 2.04, 1.85, 1.78, 1.72, and 1.51 eV, respectively for an increasing percentage of doping. The thin-film SnO2: (Al + In + F) which experiences a gap energy reduction and activation energy makes the thin film more conductive because electron mobility from the valence band to the conduction band requires less energy and faster electron movement as a result of the addition of doping.


2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000175-000182
Author(s):  
Carol Putman ◽  
Rachel Cramm Horn ◽  
Ambrose Wolf ◽  
Daniel Krueger

Abstract Low temperature cofired ceramic (LTCC) has been established as an excellent packaging technology for high reliability, high density microelectronics. The functionality and robustness of rework has been increased through the incorporation of a Physical Vapor Deposition (PVD) thin film Ti/Cu/Pt/Au metallization. PVD metallization is suitable for RF (Radio Frequency) applications as well as digital systems. Adhesion of the Ti “adhesion layer” to the LTCC as-fired surface is not well understood. While past work has established extrinsic parameters for delamination mechanisms of thin films on LTCC substrates, there is incomplete information regarding the intrinsic (i.e. thermodynamic) parameters in literature. This paper analyzes the thermodynamic favorability of adhesion between Ti, Cr, and their oxides coatings on LTCC (assumed as amorphous silica glass and Al2O3). Computational molecular calculations are used to determine interface energy as an indication of molecular stability over a range of temperatures. The end result will expand the understanding of thin film adhesion to LTCC surfaces and assist in increasing the long-term reliability of the interface bonding on RF microelectronic layers.


2016 ◽  
Vol 13 (3) ◽  
pp. 95-101 ◽  
Author(s):  
Carol Putman ◽  
Rachel Cramm Horn ◽  
J. Ambrose Wolf ◽  
Daniel Krueger

Low temperature cofired ceramic (LTCC) has been established as an excellent packaging technology for high-reliability, high-density microelectronics. The functionality and robustness of rework have been increased through the incorporation of a physical vapor deposition (PVD) thin film Ti/Cu/Pt/Au metallization. PVD metallization is suitable for radio frequency (RF) applications as well as digital systems. Adhesion of the Ti “adhesion layer” to the LTCC as-fired surface is not well understood. Although previous work has established extrinsic parameters for delamination mechanisms of thin films on LTCC substrates, there is incomplete information regarding the intrinsic (i.e., thermodynamic) parameters in the literature. This article analyzes the thermodynamic favorability of adhesion between Ti, Cr, and their oxide coatings on LTCC (assumed as amorphous silica glass and Al2O3). Computational molecular calculations are used to determine interface energy as an indication of molecular stability between pair of materials at specific temperature. The end result will expand the understanding of thin film adhesion to LTCC surfaces and assist in increasing the long-term reliability of the interface bonding on RF microelectronic layers.


2021 ◽  
Vol 10 (2) ◽  
pp. 163-169
Author(s):  
Ravinder Gaur ◽  
Himanshu Mohan Padhy ◽  
Manikandan Elayaperumal

Abstract. In this short communication, we propose a surface plasmon resonance (SPR) sensor based on a ZnO / Au hybrid thin-film material structure and experimentally investigate its sensitivity improvement. The Kretschmann-based SPR sensor utilizes ZnO thin films and nanostructures for performance enhancement. The advancement in SPR technology relies on a low-cost, high-sensitivity, and high-selectivity sensor. Metal oxide (MO) has been incorporated into the SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecule detection depends on their interaction with the ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In the future, the thin film and nanostructures of ZnO could be a potential application for miniature design, robust, high sensitivity, and a low-cost portable type of SPR biosensor to be used for on-site testing in a real-time and label-free manner. The present work includes the application of a developed SPR setup for gas sensing at room temperature using a specially designed gas cell. The change in the optical properties of dielectric layers (ZnO) with adsorption of gases (NO2) in order to develop an optical sensor has been presented. The obtained results emphasize the applications of an SPR setup for the study of interaction of adsorbed gas molecules, with dielectrics and gas sensing.


2019 ◽  
Vol 86 (7) ◽  
Author(s):  
Ahmed Ghareeb ◽  
Ahmed Elbanna

Peeling of thin films is a problem of great interest to scientists and engineers. Here, we study the peeling response of thin films with nonuniform thickness profile attached to a rigid substrate through a planar homogeneous interface. We show both analytically and using finite element analysis that patterning the film thickness may lead to direction-dependent adhesion such that the force required to peel the film in one direction is different from the force required in the other direction, without any change to the film material, the substrate interfacial geometry, or the adhesive material properties. Furthermore, we show that this asymmetry is tunable through modifying the geometric characteristics of the thin film to obtain higher asymmetry ratios than reported previously in the literature. We discuss our findings in the broader context of enhancing interfacial response by modulating the bulk geometric or compositional properties.


2021 ◽  
Vol 21 (9) ◽  
pp. 4763-4767
Author(s):  
Yu-Xin Zhang ◽  
Chien-Hung Wu ◽  
Li-Wei Yeh ◽  
Yi-Ming Chen ◽  
Kow-Ming Chang ◽  
...  

Transparent conductive oxide (TCO) semiconductors are attracted considerable attention due to a wide range of applications, such as flat panel display (FPD), touch panels, solar cells, and other optoelectronic devices. Owing to the different carrier conduction paths between n-type and P-type TCOs, the n-type TCO used in TFTs usually have high Ion/Ioff current ratio (>107) and high electron mobility (>10 cm2/V·s), P-type TCO TFTs are both lower than that of n-type one. For complementary circuits design and applications, however, both P-type and n-type semiconductor materials are equally important. For SnO thin films, it is important to adjust the ratio of Sn2+ (SnO P-type) and Sn4+ (SnO2 n-type) in order to modulate the electrical characteristics. In this investigation of post treatment for SnO thin films, both microwave annealing (MWA) and furnace annealing process with 02 ambient are studied. The results show that SnO thin films are optimized at 300 °C, 30 minutes furnace annealing, the P-type SnO/SnO2 thin film shows surface mean roughness 0.168 nm, [Sn2+]/[Sn4+] ratio as 0.838, at least 80% transmittance between 380 nm-700 nm visible light. Withthe results, SnO can be even used to fabricate high performance P-type thin film transistors (TFTs) device for future applications.


1988 ◽  
Vol 130 ◽  
Author(s):  
Paul A. Flinn

AbstractMeasurement of the curvature induced in a wafer (or other flat plate) by the stress in a thin film has long been used as a convenient and accurate technique for the determination of the stress. Numerous improvements over the years have led to instruments that provide simple and rapid measurements of stress as a function of the time and temperature for any desired thermal history. A computer controlled instrument using laser scanning will be briefly described and its capabilities and limitations discussed.Applications of the technique to a variety of thin film materials will be discussed. In addition to the effects of differences in thermal expansion, stresses associated with various deposition techniques, gain or loss of material, phase transformations and flow will be considered. In aluminum based systems, themal expansion, plastic flow and phase transformation play major roles. Refractory metals show, in addition, large stresses associated with the deposition process. In inorganic dielectric systems thermal expansion effects are usually relatively small; deposition effects and the gain or loss of material are the dominant effects. Silica based glasses formed by chemical vapor deposition, for example, show large stress changes due to gain or loss of water, and plasma deposited silicon nitride films show large effects associated with hydrogen. Overall, determination of the stress as a function of time and temperature is a valuable part of the evaluation of a thin film material for use in a VLSI device.


1995 ◽  
Vol 390 ◽  
Author(s):  
David J. Monk ◽  
Mahesh Shah

ABSTRACTStresses in thin polymer films have been studied for some time by using wafer bowing, bending beams, microstructure release, and laser holographic techniques. An alternative technique for measuring stresses in thin films is discussed in the following paper. Piezoresistive anisotropically etched single crystal silicon pressure sensors are sensitive not only to applied pressure, but also to applied package stress. Deposited passivation materials, like silicone gels and polyimides, have been observed to change the sensitivity of the pressure sensor. In the current work, a thin, conformal polymeric coating (parylene C) is being developed for these pressure sensors. This thin film has been observed to reduce the sensitivity of the device as a function of the film thickness and modulus and the silicon thickness and modulus. The parylene C thin films exhibit a consistent change in film stress during annealing indicating a modification to polymer crystallinity and a corresponding change in material properties. Qualitatively, the electrical output on the pressure sensor compares favorably with measurements taken using wafer bowing. Experimental DMA and TMA work has been performed to determine the modulus (7.84 × 105 psi) and CTE (39 ppm/°C at 25 °C) of the material. However, literature values of modulus (4.1 × 105 psi) have been used with finite element analysis to model the stress effect more accurately for the thin conformal coating on the pressure sensor device. These results indicate that the sensitivity of the pressure sensor will be reduced approximately quadratically as a function of the polymer coating thickness. An empirical function has been derived to estimate sensitivity loss as a function of substrate (i.e., initial diaphragm material) modulus and thickness and coating modulus and thickness.


2006 ◽  
Vol 21 (5) ◽  
pp. 1101-1105 ◽  
Author(s):  
S.P. Fernando ◽  
A.L. Elias ◽  
M.J. Brett

The mechanical behavior of a helically perforated thin film structure was simulated by finite element analysis. The validity of the results was confirmed by comparison to a nanoindentation measurement performed on a nickel helically perforated thin film sample. It was found that variation of the helical pitch angle from 35° to 70° resulted in a change of 1.5 times in the elastic modulus. Since the fabrication process used to create the actual samples allows for variation of the pitch angle, this result may enable the tailoring of materials for use in micro- and nanoscale devices.


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