I'm not sure if it's feature of all modern SSD or Samsung ones, but I know that those SSD use AES internally for all data (not for encryption specifically, but because they need random bits for better storage and encryption is just a bonus). User usually does not deal with it, as it's handled in firmware, but BIOS have the option to securely erase the disk which just generates new key instantly and then, obviously, it's not possible to recover any data from old sectors.