German Units?

[chemchok]

"Throwing aside [therefore] their javelins, they fought with swords hand to hand. But the Germans, according to their custom, rapidly forming a phalanx, sustained the attack of our swords. There were found very many of our soldiers who leaped upon the phalanx, and with their hands tore away the shields, and wounded the enemy from above. Although the army of the enemy was routed on the left wing and put to flight, they [still] pressed heavily on our men from the right wing, by the great number of their troops."

Commentaries on the Gallic War , an account of Gaius Julius Caesar's campaign.
It's a good read if you have the time

[The_Emperor]

'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.