Can I partition the 2 x 3tb Drives THEN RAID these partitions?

HI, I have 2 x 3 TB drives . I was wanting to use RAID to keep secure copies but would not want to use all of the 6tb capacity i.e 2 x 3 Tb as RAID. CAn I then partition each 3 TB to say 1 Tb and 2 Tb each and only RAID say the 2 x 2tb partitions? Cheers