National Academies Press: OpenBook
« Previous: Excited State Chemistry and Penning Ionization
Suggested Citation:"Summary." National Research Council. 1996. Database Needs for Modeling and Simulation of Plasma Processing. Washington, DC: The National Academies Press. doi: 10.17226/5434.
Page 54

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

ION PROCESSES, NEUTRAL CHEMISTRY, AND THERMOCHEMICAL DATA 54 TABLE 6.2 The Status of Neutral Chemistry Databases for Selected Chemistries System Status Comments SiH4 / Si2H6 / H2 (Deposition of a-Si:H, p-Si) Good Database was initially compiled for silane combustion, CVD of p-Si, and PECVD of a-Si:H for photovoltaics. SinHm / O2 / N2O Fair to good Database was initially compiled for CVD of SiO2, silane (Deposition of SiO2 oxynitrides) combustion, and atmospheric chemistry SinHm / NH3 / N2 Fair to good Database was initially compiled for CVD of Si3N4 and (Deposition of Si3N4 atmospheric chemistry CnHm / H2 Very good Database was initially compiled for combustion. (Deposition of diamond, diamond-like carbon) CnFm / H2 / O2 Fair to good The Plumb and Ryana mechanisms are ''standard'' but (Etching of SiO2, Si) applicable to a limited parameter space. A new reaction mechanism and database developed by M. Zachariahb are now available SF6 Fair to poor Interest in modeling circuit breakers and spark gaps at (Etching of p-Si, W) high pressure Database with questionable application to low pressure CCl4 Fair Need for this database is minimal due to phaseout of the (Etching of p-Si) use of CCl4. BCl3 / HBr / C12 / NF3 Poor These are examples of databases that are currently poor (Etching of p-Si, metals) but are amenable to being addressed by calculations a I. Plumb and K. Ryan, Plasma Chern. Plasma Proc. 6:11 (1986);—6:205 (1986);—6:231 (1986). b D.R.F. Burgess, M.R. Zachariah, W. Tsang, and P.R. Westmoreland, NIST Technical Note 1412 (U.S. Department of Commerce, Technology Administration, July 1995). A subset of excited state chemistry is electronic quenching and Penning ionization. These reactions are collisions involving excited states of atoms or molecules and resulting in the deactivation of the excited state (quenching) and the transfer of energy to the collision partner. When the collision partner is ionized, the process is termed a "Penning ionization." Quenching reactions are important because they can transfer energy to the collision partner producing dissociation, and they may remove intermediates for multistep ionization. Interest in the development of excimer and metal ion lasers in the 1970s and 1980s resulted in a large database for rare-gas metastable quenching. (See, for example, Velasco et al.26) In the 1980s and 1990s, interest in PECVD of a-Si:H and its alloys for photovoltaics has supplemented that database with reactions involving SiH4, Si2H6, CH4, C2H6, and GeH4.27 In many cases, these rate coefficients and cross sections are for quenching of the excited state on a particular gas, and little information is given on the identity and branching ratios of the products. Summary It is clear that a large resource for cross sections and rate coefficients is currently available in the literature. Unfortunately, this resource was developed largely for use in fields other than plasma processing, and therefore is scattered and difficult to assemble. A first and necessary task is to assemble, evaluate, and disseminate the existing data.

Database Needs for Modeling and Simulation of Plasma Processing Get This Book
Buy Paperback | $47.00 Buy Ebook | $37.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

In spite of its high cost and technical importance, plasma equipment is still largely designed empirically, with little help from computer simulation. Plasma process control is rudimentary. Optimization of plasma reactor operation, including adjustments to deal with increasingly stringent controls on plant emissions, is performed predominantly by trial and error. There is now a strong and growing economic incentive to improve on the traditional methods of plasma reactor and process design, optimization, and control. An obvious strategy for both chip manufacturers and plasma equipment suppliers is to employ large-scale modeling and simulation. The major roadblock to further development of this promising strategy is the lack of a database for the many physical and chemical processes that occur in the plasma. The data that are currently available are often scattered throughout the scientific literature, and assessments of their reliability are usually unavailable.

Database Needs for Modeling and Simulation of Plasma Processing identifies strategies to add data to the existing database, to improve access to the database, and to assess the reliability of the available data. In addition to identifying the most important needs, this report assesses the experimental and theoretical/computational techniques that can be used, or must be developed, in order to begin to satisfy these needs.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook,'s online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!