Talk:CMOS

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[edit] Simple English please?

IF somebody would just explain the job a CMOS does, that'd help http://simple.wikipedia.org/wiki/CMOS

First of all, there's no such thing as "a CMOS". CMOS chips do almost ALL electronic jobs these days; every watch, phone, computer, television, etc. is full of them, doing all those jobs. Dicklyon 22:36, 6 November 2006 (UTC)


Digital electronic jobs, at least. We can't completely discount analog systems :) Do we have an article on BiCMOS? (yes, seems we do) Edit: The task of adequately explaining CMOS in "simple" terms is an unenviable one. (though not as unenviable as simple:Quantum mechanics) -- mattb @ 2006-11-06T22:54Z
Most analog electronic jobs these days are also done by CMOS. Image sensors, ADCs and DACs, op amps, and systems made of such things, all CMOS. BiCMOS plays a minority role. Dicklyon 03:56, 7 November 2006 (UTC)
Maybe I'm missing something, but to me CMOS implies complimentary logic gates in the design; something that's not particularly useful in analog design. Sure the fabrication process for Si CMOS and Si analog ICs is similar, but I can't understand how one could justify calling the analog design "CMOS". -- mattb @ 2006-11-07T04:31Z

[edit] CMOS misnomer

(pasted from an edit in the article that should have been here in the first place) "anyone got any sources for this? i'm sure modern motherboards still store settings in battery backed ram (i know from having to pull the battery from them when people forget the bios password) the bios itself is in flash though maybe whoever wrote this peice was confusing the bios itself with the bios settings" -- Plugwash

The actual technology used to create the NVRAM varies. Generally flash memory is cheaper these days and is thus the most obvious choice for storing BIOS program settings. The battery backup is mostly for the hardware RTC in these cases. Removing the battery to clear flash memory isn't necessary (indeed, it wasn't really necessary with old CMOS RAM if the motherboard properly erased the RAM when the appropriate jumper was set) -- uberpenguin 01:54, 2005 Apr 17 (UTC)

sure you can use the jumper if you have the motherboard manual handy but often you don't. The battery on the other hand is easilly spotted and in my experiance it does reset the settings. do you know of any reliable sources saying that settings are stored in flash? Plugwash 02:32, 17 Apr 2005 (UTC)

Look up the numbers printed on some NVRAM chips. I can't give you a good reference because the best reference would probably be motherboard manuals, and those are usually written in some long lost dialect of Engrish. -- uberpenguin 03:15, 2005 Apr 17 (UTC)

[edit] thanks

THANKS FOR THE INFORMATION PROVIDED ON THE CMOS DEVICES AND THE TECHNOLOGY... I FOUND IT VERY MUCH USEFUL ... ACTUALLY I WAS LOOKING FOR SOME SIMPLE LANGUAGE FORMAT OF THE MATERIAL ON THE INTERNET FOR THE STUDENTS......... IT IS REALLY VERY NICE...........

[edit] silicon or semiconductor

Does CMOS stand for Complementary Metal Oxide Semiconductor or Complementary Metal Oxide Silicon? According to google:

  • ... Semiconductor -- 24200 matches -- [1]
  • ... Silicon -- 16300 matches -- [2]

-- Uday Bhaskar

I believe it's "semiconductor", which MOSFET and Google seem to agree with me. However I don't know if both terms are acceptable or not... Dysprosia 10:56, 5 Nov 2003 (UTC)
both expansions seems to be used pretty interchangablly. Truth is its very hard to make an igfet (the key component of cmos) in anything other than silicon (silicon dioxide gives a very robust and simple way to make an extremely thin insulating layer).Plugwash 08:55, 7 Mar 2005 (UTC)


Thank you for this information. I am a high tech professional and was looking for a definistion for this word, CMOS. After I did google and glance through a few links, I found this site very useful. Thanks Again!!!

[edit] image sensor

Here's a link i'll bookmark here about CMOS imaging.


I'm no wikipedian (yet...) but it might be a good idea to create a CMOS(image_sensor) thingie? /Erik

yeah, you can be linked here hoping to find information about the image sensor, and you find a completely unrelated article, if nobody else does it i'll give it a try when i have some time. -- Joolz 16:29, 6 Mar 2005 (UTC)
Um, this article isn't completely unrelated. A CMOS image sensor is a sensor that uses the P/N junction available in a standard CMOS process as the photodetector. Thus the image sensor can be fabbed on a normal CMOS production line, which means they get to take advantage of either (a) older 0.25um lines which have been completely amortized at this point, and so produce fairly cheap silicon or (b) newer, tighter lines which get smaller pixels on the sensor.Iain McClatchie 08:26, 7 Mar 2005 (UTC)

[edit] static power consumption

I added some info on the recent problems with static power consumption. I wonder if is is too much or too little. There is, of course a lot to be said on the subject. For instance, it is not only sub-threshold leakage, but also effects like gate tunneling and several others. The current way of handling this is to use MTCMOS, Multiple Threshold CMOS. This makes it possible to have transistors with different threshold voltages on the same chip. So we can have both high speed, high leakage gates and low speed, low leakage on the same chip. This has been used all the way back to 0.18 micrometre cell libraries.

I have heard reports of some designs that had a static power consumption of up to 50% of total power.

What do you guys think? How much shuld we write about this?

[edit] hyphens?

Where are the Missing HYPENS

CMOS stands for Complementary METAL-OXIDE-SEMICONDUCTOR.
This is NOT the same as Complementary Metal Oxide Semiconductor.

The Construction method is A base layer of N-type or

P-type Semiconductor material (usually SILICON).
An insulating layer of Silicon Dioxide is then deposited on
the semiconductor layer.

A layer of a metal usually Aluminum or tungsten is then deposited on the metal layer . Regions of both P-Type and N-type semiconductor is then made on the the surface.

This creates the necessary complementary transistor junctions needed for
the basic GATE package.
The use of the three layers of METAL,OXIDE,SEMICONDUCTOR is the derivation
of the ACRONYM MOS    NOT a mythical not existent Metal Oxide Based Semiconductor material.

[edit] Cleanup

This article is too technical, and needs to be better organized. Andros 1337 21:32, 8 Jan 2005 (UTC)

Pardon me for saying, but this article has little to no context unless you DO use highly technical terms. Trying to explain it in laymens terms would be like trying to explain vector calculus to someone who knows only basic algebra or microkernel theory to someone who has only programmed in Python; there is no context. You can't expect the article on, say, integrals to be simplified for someone with little exposure to formal mathematics, likewise you can't expect an article about an electrical engineering concept to be simplified for someone with no EE experience or knowledge... I can see a few places where clarity (and certainly organization) can be improved, but it is pretty difficult to explain CMOS in terms everyone can understand. -- uberpenguin 23:00, 2005 Jan 14 (UTC)

  • It strikes me that the article would at least seem less technical if the "history" section preceded the more technical discussion. I think it helps the layman reader if the invention, manufacturers, and applications of CMOS are given priority, with the more difficult technical details occurring later, for readers who have the necessary context and want to read further. -- Wapcaplet 23:09, 14 Jan 2005 (UTC)
  • I agree with you on that point, better organization would help a lot. -- uberpenguin 20:46, 2005 Jan 19 (UTC)

The article was not too technical, IMO, but it did need to have additional introductory material at the beginning for those readers wanting just the gist. -R. S. Shaw 04:02, 2005 Jan 21 (UTC)

This topic has plenty general interest and should give lay readers several facts:
  • CMOS is built using MOSFET transistors. See MOSFET for more info.
  • Complementary static CMOS gates have a p-network and an n-network. This is how 1's and 0's are generated and used.
  • Other ways of connected the transistors are possible. See dynamic logic and cascode for more info.
That's should keep any lay reader happily learning for hours. Which is what they came here to do. Potatoswatter (talk) 08:09, 7 May 2008 (UTC)

[edit] 2005.02.02 Edits

I am reverting this article to the version prior to Akidd dublin's edits on 2 February. The reason for this is that the material added in the introduction is already covered in the introduction and elsewhere and doesn't really clarify anything in my opinion. Furthermore it really breaks the flow of the article and doesn't fit stylistically with the rest of the content or the general Wikipedia standards. If the user who added these edits still feels they belong, could they please try to reformat them to fit better and post here explaining why they feel these changes are necessary before editing the article again. Thanks! -- uberpenguin 13:13, 2005 Feb 2 (UTC)

being stylistically: digital logic can be tricky. the article needs to be rewritten. "wire" "burn"

my NOTICE shows how the CMOS NOT gate works, and covers the power consumption. capitalization: within programming, listings look very much better, thats all.Akidd_dublin 200502061007 1049

My main problems with what you included were stylistic; they broke the flow of the article. Including an example of one basic CMOS logic implementation is a good idea, but it probably should be put in its own section, not in the introduction, and should be formatted a little bit more clearly. I don't believe including a description of a specific gate clarifies or simplifies CMOS any, but it seems ill at place in the introduction section, which is why I removed it. If you still would like to include an example, try rephrasing it to fit better with the article, post it here, and we'll talk about where would be an appropriate place to put it in the article. -- uberpenguin 13:55, 2005 Feb 6 (UTC)

the term MOS is already explained in the MOSFET article. my include would describe the term complementary and also the static nature, power is consumed by electric capacities within the structures. the include would make many lines obsolete: means more than a minor edit. indeed there are actual cpu's which are described as being CMOS, but i would guess their technology is derived from CMOS. sometimes i have read the term static design: the technology is in use for low-power applications.Akidd_dublin 200502070852

The `complementary and static nature' of CMOS is already adequately described elsewhere in the article, I don't see why you want to edit it to be more simplistic rather than more complete. Furthermore, nearly every CPU and microcontroller design within the last decade has been CMOS and not some derivative (the manufacturing process of the FETs has changed, but CMOS is a design technique not a manufacturing technique). NMOS and TTL are far too dated for the high density applications needed today. CMOS is also used in low-power applications, there are just some additional considerations for creating low-powered microprocessor. No offense, but is English your first language? I'm having a hard time understanding some of what you are saying. -- uberpenguin 14:17, 2005 Feb 7 (UTC)


let's parse the sentence:CMOS circuits burn power by charging and discharging the various load capacitances (mostly gate and wire capacitance, but also drain and some source capacitances) whenever they are switched

the circuits burn power: no charges with different electric potential are equalized.*
charging and discharging: charging contains discharging logically or would charge up forever.
various load capacitances: hhm most people can make the assumption of "various"
gate and wire capacitance: basically these are structures of integrated circuits, but i am not happy with the term wires as such.
(mostly..): electrical capacities within the silicion structure? mostly, but also.., some source..: this can vary due to the layout.
whenever they are switched: logic does not have to be clocked but usually it is.

most circuits are CMOS: as far as i know, there is also LOCMOS, SOS and if you have a mobile phone: it's GaAs technology. i am not an expert, have read PIC references and have build circuits with around twenty chip cases.

about my languages: people have never understood me.

however, i could make up examples. the article should orientate to intel, microchip, motorola documentation style, without words like "some".

probably you know yourself from programming references the feeling of instant understanding. but language does not always model the exact physics model: and its only a model. Akidd_dublin 200502071756

  • add a colon after no: have seen it like this in physic books

the SRAM article is of poor quality. the statement chips would consume around one watt is objection. by the way i know the CMOS cookbook but made the experience that circuits have become obsolete because of PAL/GAL PIC. however, i have found a 4060 in a toaster two years ago, used for timing. this would mean the 4000 CMOS logic product line. phillips is providing detailed information about what ACT and so on means.

perhaps the article should outline the timeline, and the excact terms for current circuits, if you say nearly everything nowadays would be CMOSAkidd_dublin 200502071820

In the above I see objections to the terms "burn" and "wire". I think there's some merit in changing the uses of these terms in the article:
  • "burn" - This is a sort of slang usage: I think "use" would be better.
  • "wire" - Seems a little misleading, since 'wire' seems to connotate round, flexible things. I don't know what term might fit better though. Any suggestions?
-R. S. Shaw 22:59, 7 Feb 2005 (UTC)
"burn" is indeed colloquial usage, maybe we should change that to "dissipate", which is what circuit designers use when they're being formal.
"wire" is correct. They aren't round or very flexible, but they are referred to as wires in all the english technical literature. (Sometimes they're referred to as interconnect.)
Overall, though, I agree that the article is a mess and should be rewritten. Iain McClatchie 23:06, 7 Feb 2005 (UTC)
Yes, it really is in rough shape... I'd love to do some major re-writing, but right now I'm pressed for time... I think it would also be a nice idea to create a linked article describing several CMOS logic implementations (also something in the category of `Things I Want To Do') -- uberpenguin 04:43, 2005 Feb 8 (UTC)

[edit] MIS

Is CMOS a special case of MIS (metal insulator semiconductor)?

--Abdull 17:48, 18 Jun 2005 (UTC)

CMOS is a design methodology (complimentary gate networks), not really a type of gate manufacture technology. CMOS uses MOSFET gates. -- uberpenguin 20:50, 2005 Jun 18 (UTC)

[edit] How-to tips should be moved

Is there a better article for all the how-to tips on configuring PCs? It doesn't feel to me as if they belong here; I wouldn't put a set of instructions for my CMOS wristwatch here. Where to put the how-to information? --Wtshymanski 17:18, 20 Jun 2005 (UTC)

The BIOS CMOS deserves a separate article of its own, linked from both CMOS and BIOS. The howto roadmap (it would have to be more detailed to warrant calling it tips) could then fit in better. --Shaddack 21:02, 20 Jun 2005 (UTC)
Done. Iain McClatchie 07:53, 26 Jun 2005 (UTC)

[edit] enhancement or depletion?

do they use enhancement or depletion mode mosfets? or both? - Omegatron 02:19, July 11, 2005 (UTC)

[edit] WTH happened to Image:CMOS_NAND.png?

It appears this image has been deleted for some reason. Can someone tell me why? I created that image, and if I need to tag it with some rights release that's no problem.

Iain McClatchie 21:41, 27 July 2005 (UTC)

Deleted because: "Listed at WP:PUI for 30 days and not tagged by the uploder."
Yeah, it was deleted because you didn't have a license tag. I can undelete the image description but the image is deleted forever so you'll have to re-upload it. Make sure you add tags to all your images. They should have notified you on your talk page that it was being deleted, but if you had the image on your watchlist you would have seen it, too. - Omegatron 21:52, July 27, 2005 (UTC)

I found the image very helpful. I hope you can find the time to reupload it. -R. S. Shaw 23:41, 27 July 2005 (UTC)

All right, I'll try to get to it this weekend. This time I'll put in a GFDL tag. Grrr. I definitely didn't see this on my home page or watchlist. Iain McClatchie 22:42, 28 July 2005 (UTC)

The image uses unconventional symbols for the MOSFET transistors. Usually you indicate N and P channel with an arrow - the bubble on the top two transistors is non-standard. I don't think it's quite complete, either, since multiple-input gates would have increasing thresholds. And what does "&h8203" mean? It doesn't reproduce as anything comprehensible on my little-known and obscure Web browser. --Wtshymanski 20:05, 26 August 2005 (UTC)
I removed the #8203 unicode char I put in; Firefox interprets it correctly but IE doesn't. I don't know nothin' 'bout thresholds or symbols, but I do note that MOSFET shows alternative symbols using bubbles and arrows. -R. S. Shaw 21:14, 26 August 2005 (UTC)

[edit] Stuff I'd like to see here

These are notes for myself or anyone else who feels like contributing. It seems like a lot of artwork, I guess because hardware design, especially process and layout, is quite visual.

  • Better explanation of the difference between a CMOS circuit and a CMOS process
  • Cross section of a PMOS gate, and another cross section of an NMOS gate, in a double-well process (substrate and a simple NWELL implant).
  • Same diagram, pointing out the unwanted PNP transistors and the resulting SCR. Description of latchup (forward bias the source/drain diode to well/diffusion, turn on the PNP, turn on the SCR, kablooey). Description of how latchup is prevented.

Diagrams of various major process options:

  • Cross section of PMOS and NMOS gates, triple well process
  • Cross section of PMOS and NMOS gates in a SOI process.

For each of those process options, a series of pictures showing how they get built up would be nice. This is a lot of artwork, but I think it's the best way to convey the information.

I'd also like to see a representation of the scale of modern chips. Perhaps artwork of a transistor (100 nm indicated), then an inverter (1 um indicated), that inverter amidst rows of standard cells (10 um indicated), rows of standard cells in a block (100 um indicated), and a micrograph of a chip or full chip layout (1 mm indicated) with a block labelled. Each pic could have a scale and highlight the component in the previous pic.

And, um, if anyone is going to comment that this material has to be structured, broken into many pages, yes, of course, but first it must be written and drawn, which is a lot harder.

Iain McClatchie 21:30, 30 October 2005 (UTC)

Latchup already has its own article. --Shaddack 05:24, 21 January 2006 (UTC)

[edit] About CMOS!!!!!!!!!

Hi,,

Can you please explain if their is a chip call "CMOS RAM"? Or where we can find CMOS chip? is with in ROM chip?

pat..

See CMOS RAM. It used to be a SRAM with a back-up battery, but today's it's mostly a serial EEPROM. --Shaddack 05:20, 21 January 2006 (UTC)

[edit] THANK YOU......

THANK YOU SHADDACK FOR HELP.......

pat

[edit] Comparison

Could it be said, that

?--Arnero 17:33, 27 January 2006 (UTC)

Please answere at TTL

[edit] CMOS V.S. CCD

So how do CMOS sensors compare to CCDs? I remember reading somewhere that although the CCDs are harder to manufacter, they are better for image quality; but then, I've also read that CMOS sensors are better in that way. And how do 3CCDs compare to a single CMOS? —The preceding unsigned comment was added by 24.23.6.222 (talk • contribs) .

A CMOS sensor uses a CMOS inverter per pixel as a preamplifier. This reduces the space available for the photodiode, and in turn the sensitivity and dynamic range.--Arnero 14:55, 28 January 2006 (UTC)
but presumablly it also means they can be fabricated in a standard cmos fab and i believe there is a LOT of spare capacity in older (Larger feature) CMOS fabs that people are looking to find other uses for. Plugwash 17:51, 28 January 2006 (UTC)
So what is the difference then? A CCD only needs nMOSFETs and under-utilizes a CMOS-Fab. But presumablly it needs higher quality silicon, to not loose any electrons in the very long chain to the first amplifier.--Arnero 13:34, 29 January 2006 (UTC)

In addition to high-k dielectics, another approach to gate leakage reduction is to use a silicon superlattice to enhance drive current whilst siultaneously reducing leakage. This has advantages that it can be incorporated into the production process without costly re-tooling and also superadded onto other techniques such as silicon-on-insulator (SOI), giving additive benefits. See "Addressing Gate leakage with Rerengineered Silicon" (www.reed-electronics.com/semiconductor/article/CA6418540?pubdate=3%2F1%2F2007Lesterruss 10:55, 25 March 2007 (UTC)

[edit] CMOS' invention

Who invented CMOS technology? --Abdull 22:00, 30 November 2007 (UTC)

According to this page, Frank Wanlass of Fairchild Semi in 1963. Others say Wanlass and Sah. Dicklyon 05:58, 1 December 2007 (UTC)