RAID won't protect you against data corruption...but time machine will.
Since when does Time Machine have any form of checksum or integrity check whatsoever? I have seen time machine backups that suffered from silent corruption and as a result were unusable. The drives themselves were fine but the data written to them was bad.
To protect against silent corruption you really need a backup system that uses a resilient filesystem like ZFS or ReFS which make extensive use of checksums to detect corrupted blocks and repair them from other copies. Typically those filesystems also require the use of ECC memory to ensure that transient memory errors doesn't cause any problems.