'm not entirely sure, but i suspect not. To form a phlanax required a huge amount of dicipline and i don't think the barbarian tribes had that.
That is because of the historical bias against those cultures by historians for many years. Painting them as unsophisticated savages. But they were very clever in combat, and we must also remember that the Germanic Tribes were a constant thorn in the side of Roman Empire until its fall, despite numerous attemts to campaign against them.

and as the above posts shows the Germans did use a Phalanx formation in battle, as caesar's accounts of his Gallic campaign shows.