You're saying transistors in the chips are IGBT? Because if the terminals are C and E, the control should be Base (for the case of BJT).
But I believe it should be IGBT, as BJT is no longer used.

Lemme put my 2 cents in. The the EE business there are a few ways to make things smaller and in this case, computer devices smaller. Granted digital electronics and microtronics isn't my subfield, but i do know how things work. Although you can PM Ikanayam if you want to know more lol since his field is dedicated to microprocessors.

Either way, the first way to make things smaller is markedly to cram more shite into a smaller area, which means more processors into a singular microprocessor. You don't use IGBTs for switches, FETS with individual logic cells are used. Anyways, but making the production process smaller and multileveled, you're essentially cramming more transistors into the same area, thus you can make smaller chips.

The limits of this are dependent on the materials used, the gate construction, the routing of the microwires and so on. But generally you get the picture lah.

Secondly, to cram more shit into stuff, you need to integrate more discrete components into the system, or increase route density so that more options exist when it comes to component placement. The easiest way is to stuff more conductive layers into a PCB (circuit board), so that routing becomes easier and the physical layout can have it's density increased.

Thirdly, you always have the problem of heat, cramming so much into such small areas always gives you a problem with heat. By adopting either lower powered components or adopting better cooling, technically, the component density around "hot spots" can be increased, giving you a smaller package by default.

Agreed.

Last if not least, no, the military does no possess better than consumer electronics technology. They usually follow DOD MILSTD when it comes to stuff like temp curve stability, shock reliability and so on. Meaning that it's no more advanced than normal stuff we use, but instead of having a transistor in a single ceramic plastic case, military components come in metal canned LMC style casings. Resistors also come in fireproofed coating and the higher spec RNXX series. The Military emphasizes it's technology towards hardened reliability and the ability to operate in differing environments, often they will choose to use battle toughened last generation technology rather than latest generation stuff.

You are correct that military spec require more stress test requirement on extreme temp (cold and high), shock requirement.

However, I have to disagree that military components are no more advanced than the normal stuff we use.

In microwave technology (wireless network), some spectrum have been reserved for military, and these spectrum require different requirement on EE devices, which is not usually sub-con to ordinary manufacturer.

In computer graphic randering for 3D modelling technology, one of the report specifically mentioned that the current companies like ILM, PIXAR, silicon graphic comes first only after discounting the similar technology used in military.

This is called "Art of War".

Even the F-16 plane fighter used in US and the one sold to US friendly allies are of different spec.