Does a hotter processor run faster?

Question

I heard from a physicist that when silicon gets hotter it can conduct more electricity through it. He said:

"Silicon is going to have a pretty good structure, it's going to have higher melting point, but as we increase the temperature we start to vibrate those atoms and it can actually be a conductor. It's something we call a semiconductor and so we can vary the amount of electricity conducting through it. And one way we can do this is to dope it, we can add different elements to it, different other atoms, we can n-type or p-type dope it, and we can add either electrons or lack of electrons, and so it allows us to create transistors."

This is of course not written but spoken text in this video.

But it made me think, when a silicon chip get hotter does that mean it gets faster and produces better performance, and does this count for processors as well?

I'm aware that the question is a bit odd, especially because I do not fully understand the architecture of a processor, so I'm curious about what the answer is.

Answer 1

The biggest problem with your thought process, is that if the processor gets too hot then it is no longer a semi-conductor. It cannot accurately control the signals. What you end up with is a lot of errata and very little data. So more current is getting through, but less of that current is information.

Answer 2

The perception here is that the silicon is the conductor, trying to find the right words to say this, I refer to the wiki.

Pure silicon has too low a conductivity (i.e., too high a resistivity) to be used as a circuit element in electronics. In practice, pure silicon is doped with small concentrations of certain other elements, a process that greatly increases its conductivity and adjusts its electrical response by controlling the number and charge (positive or negative) of activated carriers.

In common integrated circuits, a wafer of monocrystalline silicon serves as a mechanical support for the circuits, which are created by doping, and insulated from each other by thin layers of silicon oxide, an insulator that is easily produced by exposing the element to oxygen under the proper conditions. Silicon has become the most popular material to build both high power semiconductors and integrated circuits. The reason is that silicon is the semiconductor that can withstand the highest temperatures and electrical powers without becoming dysfunctional due to avalanche breakdown (a process in which an electron avalanche is created by a chain reaction process whereby heat produces free electrons and holes, which in turn produce more current which produces more heat).

http://en.wikipedia.org/wiki/Silicon

Thanks wiki. As you can see from my perpective the silicon wafer is not the paths and traces and switches, but more like the medium by which these cool electronic activities take place on and with.
As stated in the video, it is the etching, and the doping and the addition of other materials, that really makes up the integrated chip, and the high conduction, and electronic switching in the right places. So Changing the conduction of the wafer thing itself, is not a benefit.

Also semiconductor junctions have a maximum Junction Temperature

Various physical properties of semiconductor materials are temperature dependent. These include the diffusion rate of dopant elements, carrier mobilities and the thermal production of charge carriers.

Basically as they get hotter there is a much higher chance that the dopants may move and so the functional barriers between doped sides of the junction may change. This can cause the p-n junction to change irreversibly and alter the operating characteristics of the junction. This can alter the resistance characteristics of the junction and may produce more heat which in turn affects the junction properties thus leading to thermal runaway.

Carrier mobility and charge carriers refers to the number of electrons available to move within the material and temperature affects this quite a lot too. Again these characteristics affect the overall resistance and heat generation of the device.

The other silicon components around the board , it is similar, while doped silicon makes up the gates and does all the fancy electronics, and it does so at a very wide range of temperatures, the package which this stuff is stuffed into is an insulator is still important to stay together, not char or burst apart when the temperatures get to high.

Answer 3

(...) as we increase the temperature we start to vibrate those atoms and it can actually be a conductor.

The silicone is used both for isolation and for conducting a current (it is mixed with other stuff for these opposing purposes). The maximum operational temperature of a transistor varies between roughly 60-100 degrees Celsius. If the temperature rises above the specified maximum, errors will occur in the CPU and the heat will likely damage the transistors.

A hot CPU may conduct more electrical current than a cool one, but that will not increase the computational performance of the chip.