Now let′s walk through the (many) steps it takes to fabricate this transistor:
First a layer of SiO2
is grown on the silicon substrate by heating in O2 gas.
(Si is shown here in blue but it is actually metallic-charcoal in color).
Then a layer of Si3N4 is grown by heating in combination of NH3 and SiH4.
NOTE: to "see" the gas molecules, we′ve had to exaggerate their size, but only by about 50 times. That gives a feel for how small modern transistors are: only a few thousand atoms across!