ALCVD AlO/sub x/ barrier layers for magnetic tunnel junction applications

Ultrathin AlO/sub x/ layers 5-25 /spl Aring/ thick were deposited using the atomic-layer chemical vapor deposition technique. A magnetic thickness loss of /spl sim/ 1 /spl Aring/ has been estimated at CoFe-AlO/sub x/ or NiFe-AlONiFe-AlO/sub x/ interfaces. The two-dimensional integrity of the thin AlO/sub x/ films at thickness >7 /spl Aring/ has been validated by the differential switching of two magnetic layers sandwiching a ultrathin AlO/sub x/ layer and the distinct cross-sectional transmission-electron-microscopy images. No appreciable tunnel magnetoresistance effect has been measured from the fabricated magnetic tunnel junction devices. A proper in situ treatment prior to and/or after AlO/sub x/ deposition and a proper protection of the underlying magnetic layer are expected for further improvements.