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Title: MEMS characterization LDRD:Final report (FY03-FY05).


No abstract prepared.

; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
OSTI Identifier:
Report Number(s):
TRN: US200614%%653
DOE Contract Number:
Resource Type:
Technical Report
Country of Publication:
United States
42 ENGINEERING; MICROELECTRONIC CIRCUITS; MINIATURIZATION; TECHNOLOGY ASSESSMENT; Aging tests (Materials); Molecular integrated microsystems.; Mass spectrometry.; Microelectromechanical systems.

Citation Formats

Ordonez, Therese A., Zavadil, Kevin Robert, Brown, Jason R., Kent, Michael Stuart, Simpson, Regina Lynn, Tallant, David Robert, Ohlhausen, James Anthony, Garcia, Manuel Joseph, and Thornberg, Steven Michael. MEMS characterization LDRD:Final report (FY03-FY05).. United States: N. p., 2005. Web. doi:10.2172/883489.
Ordonez, Therese A., Zavadil, Kevin Robert, Brown, Jason R., Kent, Michael Stuart, Simpson, Regina Lynn, Tallant, David Robert, Ohlhausen, James Anthony, Garcia, Manuel Joseph, & Thornberg, Steven Michael. MEMS characterization LDRD:Final report (FY03-FY05).. United States. doi:10.2172/883489.
Ordonez, Therese A., Zavadil, Kevin Robert, Brown, Jason R., Kent, Michael Stuart, Simpson, Regina Lynn, Tallant, David Robert, Ohlhausen, James Anthony, Garcia, Manuel Joseph, and Thornberg, Steven Michael. Thu . "MEMS characterization LDRD:Final report (FY03-FY05).". United States. doi:10.2172/883489.
title = {MEMS characterization LDRD:Final report (FY03-FY05).},
author = {Ordonez, Therese A. and Zavadil, Kevin Robert and Brown, Jason R. and Kent, Michael Stuart and Simpson, Regina Lynn and Tallant, David Robert and Ohlhausen, James Anthony and Garcia, Manuel Joseph and Thornberg, Steven Michael},
abstractNote = {No abstract prepared.},
doi = {10.2172/883489},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}

Technical Report:

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  • The goal of this project was to develop novel hydrogen-oxidation electrocatalyst materials that contain reduced platinum content compared to traditional catalysts by developing flexible synthesis techniques to fabricate supported catalyst structures, and by verifying electrochemical performance in half cells and ultimately laboratory fuel cells. Synthesis methods were developed for making small, well-defined platinum clusters using zeolite hosts, ion exchange, and controlled calcination/reduction processes. Several factors influence cluster size, and clusters below 1 nm with narrow size distribution have been prepared. To enable electrochemical application, the zeolite pores were filled with electrically-conductive carbon via infiltration with carbon precursors, polymerization/cross-linking, and pyrolysismore » under inert conditions. The zeolite host was then removed by acid washing, to leave a Pt/C electrocatalyst possessing quasi-zeolitic porosity and Pt clusters of well-controlled size. Plotting electrochemical activity versus pyrolysis temperature typically produces a Gaussian curve, with a peak at ca. 800 C. The poorer relative performances at low and high temperature are due to low electrical conductivity of the carbon matrix, and loss of zeolitic structure combined with Pt sintering, respectively. Cluster sizes measured via adsorption-based methods were consistently larger than those observed by TEM and EXAFS, suggesting , that a fraction of the clusters were inaccessible to the fluid phase. Detailed EXAFS analysis has been performed on selected catalysts and catalyst precursors to monitor trends in cluster size evolution, as well as oxidation states of Pt. Experiments were conducted to probe the electroactive surface area of the Pt clusters. These Pt/C materials had as much as 110 m{sup 2}/g{sub pt} electroactive surface area, an almost 30% improvement over what is commercially (mfg. by ETEK) available (86 m{sup 2}/g{sub pt}). These Pt/C materials also perform qualitatively as well as the ETEK material for the ORR, a non-trivial achievement. A fuel cell test showed that Pt/C outperformed the ETEK material by an average of 50% for a 300 hour test. Increasing surface area decreases the amount of Pt needed in a fuel cell, which translates into cost savings. Furthermore, the increased performance realized in the fuel cell test might ultimately mean less Pt is needed in a fuel cell; this again translates into cost savings. Finally, enhanced long-term stability is a key driver within the fuel cell community as improvements in this area must be realized before fuel cells find their way into the marketplace; these Pt/C materials hold great promise of enhanced stability over time. An external laser desorption ion source was successfully installed on the existing Fourier transform ion-cyclotron resonance (FT-ICR) mass spectrometer. However, operation of this laser ablation source has only generated metal atom ions, no clusters have been found to date. It is believed that this is due to the design of the pulsed-nozzle/laser vaporization chamber. The final experimental configuration and design of the two source housings are described.« less
  • Residual dense non-aqueous phase liquid (DNAPL) contamination continues to be one of the most challenging remediation and characterization problems at SRS and sites around the world. Chlorinated solvents were usually released as DNAPLs to/the subsurface where they move in an unstable fashion driven by gravitational and,capillary forces. They are often retained in small discrete blobs in fine grain materials in the vadose zone and contaminate ground water by slow continuous release through dissolution and diffusion. Locating these small sources is a difficult but crucial part of remediating a contaminated site. Several methods have been developed to locate subsurface DNAPL butmore » nearly all are intrusive and can only identify DNAPL in close proximity to the access hole. Minimally invasive geophysical methods to locate residual DNAPL have been proposed and developed but few methods are capable of the spatial resolution required. Complex resistivity measurements sensitive to DNAPL (perchloroethylene) interactions with clay (smectite) have recently been shown to have promise in laboratory experiments. Based on these laboratory results, field tests of the complex resistivity technique were performed at the A-014 outfall.« less
  • New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo providemore » corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer or inhibitor. Comparable metallic alloys such as SAM2X5 and SAM1651 may also experience crevice corrosion under sufficiently harsh conditions. Accelerated crevice corrosion tests are now being conducted to intentionally induce crevice corrosion, and to determine those environmental conditions where such localized attack occurs. Such materials are extremely hard, and provide enhanced resistance to abrasion and gouges (stress risers) from backfill operations, and possibly even tunnel boring. The hardness of Type 316L Stainless Steel is approximately 150 VHN, that of Alloy C-22 is approximately 250 VHN, and that of HVOF SAM2X5 ranges from 1100-1300 VHN. These new materials provide a viable coating option for repository engineers. SAM2X5 and SAM1651 coatings can be applied with thermal spray processes without any significant loss of corrosion resistance. Both Alloy C-22 and Type 316L stainless lose their resistance to corrosion during thermal spraying. Containers for the transportation, storage and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) with corrosion resistant coatings are envisioned. For example, an enhanced multi-purpose container (MPC) could be made with such coatings, leveraging existing experience in the fabrication of such containers. These coating materials could be used to protect the final closure weld on SNF/HLW disposal containers, eliminate need for stress mitigation. Integral drip shield could be produced by directly spraying it onto the disposal container, thereby eliminating the need for an expensive titanium drip shield. In specific areas where crevice corrosion is anticipated, such as the contact point between the disposal container and pallet, HVOF coatings could be used to buildup thickness, thereby selectively adding corrosion life where it is needed. Both SAM2X5 & SAM1651 have high boron content which enable them to absorb neutrons and therefore be used for criticality control in baskets. Alloy C-22 and 316L have no neutron absorber, and cannot be used for such functions. Borated stainless steel and G« less
  • Recently, a great deal of interest has developed in manufacturing processes that allow the monolithic integration of MicroElectroMechanical Systems (MEMS) with driving, controlling, and signal processing electronics. This integration promises to improve the performance of micromechanical devices as well as lower the cost of manufacturing, packaging, and instrumenting these devices by combining the micromechanical devices with a electronic devices in the same manufacturing and packaging process. In order to maintain modularity and overcome some of the manufacturing challenges of the CMOS-first approach to integration, we have developed a MEMS-first process. This process places the micromechanical devices in a shallow trench,more » planarizes the wafer, and seals the micromechanical devices in the trench. Then, a high-temperature anneal is performed after the devices are embedded in the trench prior to microelectronics processing. This anneal stress-relieves the micromechanical polysilicon and ensures that the subsequent thermal processing associated with fabrication of the microelectronic processing does not adversely affect the mechanical properties of the polysilicon structures. These wafers with the completed, planarized micromechanical devices are then used as starting material for conventional CMOS processes. The circuit yield for the process has exceeded 98%. A description of the integration technology, the refinements to the technology, and wafer-scale parametric measurements of device characteristics is presented. Additionally, the performance of integrated sensing devices built using this technology is presented.« less
  • The monolithic integration of MicroElectroMechanical Systems (MEMS) with the driving, controlling, and signal processing electronics promises to improve the performance of micromechanical devices as well as lower their manufacturing, packaging, and instrumentation costs. Key to this integration is the proper interleaving, combining, and customizing of the manufacturing processes to produce functional integrated micromechanical devices with electronics. The authors have developed a MEMS-first monolithic integrated process that first seals the micromechanical devices in a planarized trench and then builds the electronics in a conventional CMOS process. To date, most of the research published on this technology has focused on the performancemore » characteristics of the mechanical portion of the devices, with little information on the attributes of the accompanying electronics. This work attempts to reduce this information void by presenting the results of SPICE Level 3 and BSIM3v3.1 model parameters extracted for the CMOS portion of the MEMS-first process. Transistor-level simulations of MOSFET current, capacitance, output resistance, and transconductance versus voltage using the extracted model parameters closely match the measured data. Moreover, in model validation efforts, circuit-level simulation values for the average gate propagation delay in a 101-stage ring oscillator are within 13--18% of the measured data. In general, the BSIM3v3.1 models provide improved accuracy over the SPICE Level 3 models. These results establish the following: (1) the MEMS-first approach produces functional CMOS devices integrated on a single chip with MEMS devices and (2) the devices manufactured in the approach have excellent transistor characteristics. Thus, the MEMS-first approach renders a solid technology foundation for customers designing in the technology.« less