stretch:
There is no such thing--Micron and Infineon are competing memory chip makers. They both sell their memory chips to memory board makers, who produce the final modules. However, Crucial is the retail division of Micron, which gets the best Micron chips, obviously. So Crucial is retail Micron memory. Crucial is the only example of a chip maker also producing modules.
One more note: I didn't mean that there is no retail memory using Micron memory chips. I meant that there is no such thing as retail memory called "Micron". Micron's only retail product is Crucial memory. If memory is advertised as "Micron" memory, it is memory produced by another company using Micron chips. And if that other company is not named, you know it is generic.