What, no safe space to retreat to?

​@@demef758 back in those days, we called that the bench, and people there were called bench warmers.

Given the spread, A grade was very sensible. I wonder why you complained and if your academic life was harsh back then is sarcasm or not.

Meritocracy in practice!

Bravo

Yes, the MOSFET closely resembles the way the old vacuum tube works. In fact, tubes are more like JFETs than MOSFETs because to actually shut off a vacuum tube, you need to apply a negative voltage to the grid, just as you need to apply a negative voltage to a JFET's gate to shut it off.

You're talking about depletion mode vs enhancement mode. Depletion mode devices are on with no gate voltage and switch off when the gate is pulled 'negative'. Enhancement mode devices are off with no gate voltage and switch on when the gate is pulled 'positive'. As far as I know, JFETs are always depletion mode devices. Most MOSFETs are enhancement mode devices but depletion mode MOSFETs exist. Valves were very similar to depletion mode FETs. They definitely were not just on/off devices. Like transistors, they could be used in linear mode or as switches.

@@nicholasvinen I appreciate you explaining the errors in the original commenter's statements. I picked up on that also. I endorse your response in the context of this forum.

another correction might be that tubes were not used as switches in majority of their applications.... there was a lot of stuff happening right between on and off...ie most of it... essentially, tubes are modulation devices....

What about a p-channel MOSFET. Put a voltage on the grid; there is no hole current. Remove the grid voltage, still no hole current?

CD4000 series, THE Classic!

@@ccshello1 I believe I was the first engineer to design-in CD4000 CMOS devices into a product in New Zealand - early 1970. It was so EASY to use this logic. But one detail of my schematic for the impulse counter boards was overlooked by the draftsperson, and 20 PCB's were made and put into service. Oh my! About 3 months after commissioning the power-load-monitor for a large paper mill, the first card failed. Reason? They had all been operating perfectly well without a Vdd supply. And functioned just fine because of the input protection diodes on each chip pumping the supply rails from input signals only - until one card did not. Quickly fixed of course. Very red face over that, but it taught me to henceforth go deep on the physical performance of any design and thoroughly inspect the actual physical details around anything I subsequently designed. I was not quite 20 years old at the time.

Me Too. I have all the Motorola IC Design Books, heavily marked up.

I used to design with CMOS. Loved the technology. When run in the static regime it would draw next to no power. Made an alarm for my garden shed. It ran for about ten years on the same PP3 battery!

Oh... but you see - he's no ASIAN, so it doesn't count.

I presume you are referring to 11:15

He has been using this block diagram for quite some time that shows the Source and Drain in different colors, which imply they are different materials or are doped differently, when in fact the Source and Drain regions are, effectively, identical in construction, and what makes one a “source” and the other a “drain” really only has to do with how the transistors are hooked up and connected to the rest of the circuit. I think it would behoove him to update his cartoon model to show the source and drain in the same color, indicating they are identical in construction and composition. The colors should be used to indicate whether the regions are n-type or p-type, and therefore the colors can be used for both “wells” (silicon substrate under the transistor) and “active areas” (source, drain)

Yup, to add, NMOS is named after the activated/inverted channel, the chemical doping is the opposite of the 'ON' channel. When gate is turned on, the p-doped Si inverts to form n-channel. A separate FET device is the TFT with metal S/D where n-type channel gets accumulation and becomes even more conductive, no need for inversion.

Source/Drain doping determines the transistor type. If the doping is n-type, it's NMOS. If the doping is p-type, it's PMOS. There could be only one well in a more straightforward process or two wells in a more advanced process.

this is only 25 mins but seemed that Faggin was noticeably absent

It’s worth noting that William Shockley was an avowed racist and eugenist.

During the brief hey-day of NMOS, depletion mode transistors were VERY common thanks to ion implantation, which allowed manufacturers to place ions under the gate, "pre-inverting" the surface. Aside from that, you are correct that finding a discrete N-channel depletion-mode device was like trying to find Big Foot.

Look at it through the eyes of the Scientific Method …. Electrons flow through traces of a electro conducting metal embedded in a di-electric material …..

"Magic is any technology so advanced that it's working principles are completely incomprehensible to the observer". Most things are magic to most people. There was a time when producing fire from something not already on fire was magic.

Oh that's not right at all. Silicon is considered a metalloid, not a metal. The part about wizards and secret runes, though? Spot on.

I was around when dual-layer metal was being attempted. It was not uncommon back then to get zero yields due to "pin holes" in the insulating SiO2 insulator between the two layers that shorted the two metal layers. Thankfully, they figured it out over time!

@@demef758 I suppose the only thing to miss about single metal is how easdy it was to reverse engineer the chips. For a while, I had a side hustle doing that for some Intel chips and the NEC floppy disk controller.

Lots of good chips were designed with a single layer of aluminum.

@@allanflippin2453 You cannot tell anyone, but our company also used to de-cap chips, and reverse engineer them.

Sorry about the JavaScript 😅

@@fensoxx It's a blast, actually; like ATARI player-missile graphics on crack

There are support groups for people struggling with JavaScript related cognitive impairment. And remember: Anything is better than suicide :P

@@fensoxx I'm currently 'trying' to learn javascript, what do you mean?

In the (more common) case of an enhancement type MOSFET yes, but a depletion type MOSFET also exists and takes a negative voltage to turn off. Both existed early on, though the enhancement type version was the first one to be made

Go through his back-catalogue and find the episode on FinFETs. I don't recall the title, but I know it's there.

And don't forget Schottky. His diodes were better.

He was Faggin

Vacuum tubes and FETs use the same process - electron flow control via electric fields.

It's mainly to do with the transfer curve. Valves and FETs are both transconductance devices, ie, use voltage to control a current. But they have different curves of input voltage vs output current. They also saturate differently. It is possible, but not easy, to make a JFET have a curve very much like a signal valve. It requires careful biasing and usually adjustment of every device built.

kzfaq.info/get/bejne/qNyiaNpmx8jGmmg.html

Two months ago??? What?!

@@TheLegendaryHacker for the same reason, early access tier on Patreon! I’m part of a tier that gets some videos early but not all. My Patreon bill is also so high lol. The scanning microscope one got released eventually.

kzfaq.info/get/bejne/qNyiaNpmx8jGmmg.htmlsi=3BXx1SSjtcYkarNM

A hole, event though is has "mobility" and a speed, does not actually travel, since it is a "vacancy" or essentially a "missing" part of the bulk. What travels is the energy wave around the hole, which translates as an evanescent wave through the structure, where the outer electrons are essentially a protective wall, around the vacancy. This electron bubble continues to move toward some potential, until it is absorbed in some Fermi band, or hits some kind of interference, such as a defect within the structure, where that energy shell is disrupted in random directions, and then the hole collapses into the thermal zone. The hole "per se" contains no energy, but the shell does. A crude analog might be a tornado, or an eddy current. The "vacancy" inside those also can contain no significant mass or other obvious energy, and it can be a vacuum, but the shell can suck up whole houses.

If you want REAL drama, study the invention of the transistor at Bell Labs under Shockley. Prior to this endeavor, Shockley was reported to be a real good guy to work under. But after it, he lost his marbles, jealous as hell of Bardeen and Brattain who found that Shockley's original idea would not work, and then those two had the temerity to go off and create the device that did work (i.e., "demonstrated gain"). Shockley was never the same after that, eventually quit the Labs, and headed to the West Coast. This move eventually led to the creation of Fairchild Semiconductor where the planar transistor and integrated circuit (the REAL integrated circuit, not TI's Kilby transistor that was NEVER used to manufacture a single IC) were perfected.

6:49 haha oh dang man you're having some trouble this time. George Daley is written onscreen but you read it like "dacey" -- which is correct. George Dacey.

Yeah... about that... For historical reasons, that nobody bothered correcting, your intuitive idea is correct, but the established nomenclature is the opposite of what actually happens. Sorry. It bothers me too.

Negative does repel electrons.

@@andersjjensen yeah they guessed the electron charge wrong and by the time they actually found out what it really was it was too late to change everything to how things really are. So here we all are today with negatively charged electrons. Most of the time it doesn't really matter. But when it matters then it does.

Opposites attract and likes repel. Electrons are negatively charged.

@@1pcfred Okay, so negative voltage has a positive charge then?

@@vulpo voltage is the potential electrical difference between two points. In the conventional model electrons flow from the negative to the positive. Which is backwards from what one may expect. It's certainly backwards from what the people that defined it had thought. But they had no way of knowing. They didn't even know what electricity was. But they knew it had a polarity. So they decided one side was positive and the other negative. By the time anyone found out any better the conventional model was too entrenched to change it then. So we're stuck with it now.