Lots of people say "silicone valley" when they mean "silicon valley."

Silicon is the shiny stuff that computer chips are made of.

Silicone is the stuff you buy at the hardware store to fix squeaky hinges. It's also used in cosmetic surgery.

As you can see, silicone (with an E on the end) and silicon (no E) are two different things. they just happen to be spelled similarly, but that's the only thing they have in common.