It's more of a weak period than a strong comma; both sides of it need to be complete sentences.

I'm sorry, but the example in your comment is nonstandard usage. The part after the semicolon would typically be an independent clause, whereas the "because" marks yours as a dependent clause.

There are still comma-like uses though. The major one I can think of is as a separator in a list where each element is long, possibly containing commas of its own.

You didn't quite get it right; adding "because" removes the need for a semicolon. Take out that single word, and your sentence becomes proper.