I'm a bit curious about that. Because 2 sq mm is like 1.4 x 1.4 mm. It takes a border of at least 300u to fit the ring, that leave only 0.64 sq mm of useful area to put something inside. Also, can you package something this small ? Because if users need to test / characterize, it needs to be packaged. Unless you only target institution that have a whole wafer probing setup but then that limits to only big entities, no way some random designer could do that on his own.