Cosmic rays and transistors

Discussion in 'General Electronics Chat' started by Nathan Hale, Apr 7, 2016.

  1. Nathan Hale

    Thread Starter Active Member

    Oct 28, 2011
    125
    2
    Hi folks! Hope all is well! I was just reading an article about cosmic rays.
    The article said "Cosmic rays have sufficient energy to alter the states of circuit components in electronic integrated circuits, causing transient errors to occur, such as corrupted data in electronic memory devices, or incorrect performance of CPUs, often referred to as "soft errors" (not to be confused with software errors caused by programming mistakes/bugs). This has been a problem in electronics at extremely high-altitude, such as in satellites, but with transistors becoming smaller and smaller, this is becoming an increasing concern in ground-level electronics as well."

    Can some one please let me know why smaller transistors have a higher probability of being affected by cosmic waves? Why would the size of a transistor matter?
    Thanks for the replies!
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    It's less likely to be hit, by virtue of being smaller, but I'm guessing the energy is relatively larger and has a greater effect on the smaller device. Is an elephant affected? No. Is a virus? Maybe.
     
  3. Aleph(0)

    Member

    Mar 14, 2015
    342
    322
    I can just say that 100kev gamma dose rate of like 500 Gy per minute (according ionization chamber survey meter) totally crashes tablets and phones! Also there is app that makes phone work like GM counter by counting flipped camera sensor pixels. Is not accurate but fact that it works at all to super low level says something really unkind about cmos:eek:!
     
    Last edited: Apr 8, 2016
  4. Aleph(0)

    Member

    Mar 14, 2015
    342
    322
    PS Are you same Nate Hale who's unhappy that you can only die once:p?
     
  5. dl324

    Distinguished Member

    Mar 30, 2015
    3,234
    619
    Can you post a link to the article? The problem has affected devices at sea level for decades.
    Each node in an integrated circuit has what's known as a "critical charge" which is the amount of charge required for a node to change states. Reducing capacitance and supply voltage has had more impact than transistor size.

    In the 70's Intel famously had a problem with soft errors in a DRAM. Gordon Moore (and likely others) thought it was from cosmic rays and Intel purchased some lead bricks to build an enclosure to block them. It turns out that the problem was alpha particles coming from the ceramic package. Moore is a fishing aficionado and used some of the lead to make his own sinkers.
     
    Last edited: Apr 8, 2016
  6. Nathan Hale

    Thread Starter Active Member

    Oct 28, 2011
    125
    2
    yes , thats me!
     
    Aleph(0) likes this.
  7. Nathan Hale

    Thread Starter Active Member

    Oct 28, 2011
    125
    2
    https://en.wikipedia.org/wiki/Cosmic_ray#Effect_on_electronics

    https://en.wikipedia.org/wiki/Cosmic_ray#cite_note-77
     
  8. BR-549

    Well-Known Member

    Sep 22, 2013
    1,981
    388
    "This has been a problem in electronics at extremely high-altitude, such as in satellites, but with transistors becoming smaller and smaller, this is becoming an increasing concern in ground-level electronics as well."

    Where's that at?
     
  9. RichardO

    Well-Known Member

    May 4, 2013
    1,230
    382
    One fix was to coat the DRAM die with polyimide (Kapton).
    There were also problems with the ceramic packaging of the DRAM's emitting alpha rays. This was solved by making sure the clay used to make the ceramic did not contain decaying radioactive material.
     
  10. dl324

    Distinguished Member

    Mar 30, 2015
    3,234
    619
    Not likely. Neutrons from cosmic rays can penetrate tens of feet of rock. The usual way to make integrated circuits less susceptible is to increase the critical charge.
    No one knew that before Intel's investigation. In Intel's case, the problem was caused by using water downstream from an old uranium mine.
     
  11. RichardO

    Well-Known Member

    May 4, 2013
    1,230
    382
    Not neutrons but alpha particles -- a byproduct of cosmic rays hitting the atmosphere. And, yes increasing the number of electrons that store the memory state helps.
    http://eesemi.com/soft-error.htm

    That I did not know. The above reference shows that the package also emits alpha particles.
     
Loading...