High throughput continuous pulsed laser deposition process and apparatus

Abstract

The present invention relates to an apparatus and method for forming a high-temperature superconducting film on a long tape substrate at speeds suitable for large-scale production. The method includes a spooling system for use in a high-throughput, continuous pulsed laser deposition (PLD) process in which a superconducting layer, such as yttrium-barium-copper-oxide (YBCO), is deposited atop a buffered metal substrate tape that is translated through one or more deposition chambers via the action of a reel-to-reel spooling system and a conductive-radiant multi-zone substrate heater. It also optionally includes a multi-target manipulator apparatus and multiple laser beams in which multiple targets are impinged upon simultaneously.

1 . A multi-chamber vacuum coating apparatus for coating a substrate tape utilizing PLD and a reel to reel tape transport system comprising 
 a payout spool chamber containing at least one spool of uncoated substrate tape;    one or more deposition chambers;    a take-up spool chamber capable of accommodating at least one spool of coated substrate tape;    wherein the one or more deposition chambers comprises a substrate heater, a motorized target manipulator, and at least one target mounted on the target manipulator where the target manipulator imparts rotary and oscillatory motion to the at least one target;    the payout chamber and the deposition chamber both having an opening therein of sufficient dimension to permit at least one translating tape to be inserted therethrough;    the deposition chamber and the take-up spool chamber both having an opening therein of sufficient dimension to permit at least one substrate tape to be inserted there through;    the one or more deposition chambers each have the substrate heater and the target manipulator disposed therein such that the heater and the at least one target manipulator define a deposition zone therebetween; and    the exterior wall of the apparatus contains openings for at least one laser beam.    
   
   
       2 . The apparatus of  claim 1  wherein there is one deposition chamber.  
   
   
       3 . The apparatus of  claim 1  wherein the heater is a multizone heater.  
   
   
       4 . The method of  claim 1  wherein the exterior wall of the apparatus contains openings for multiple laser beams.  
   
   
       5 . The apparatus of  claim 1  wherein multiple targets are mounted on the target manipulator.  
   
   
       6 . The method of  claim 1  wherein the spool chambers are sized to accommodate from about 2 to about 20 spools of substrate tape.  
   
   
       7 . The apparatus of  claim 1  wherein the spool chambers are sized to accommodate from about 4 to about 12 spools of substrate tape.  
   
   
       8 . The apparatus of  claim 1  wherein the multizone heater comprises three zones.  
   
   
       9 . The apparatus of  claim 1  also containing seals in the opening in the chamber walls that maintain a selected pressure differential between the chambers.  
   
   
       10 . A method for the continuous production of long lengths of HTS coated tape via the deposition of HTS material onto a translating buffered metal substrate tape using utilizing the apparatus of  claim 1  comprising the steps of: 
 loading at least one payout spool of buffered substrate tape into a payout spool chamber;    lacing the at least one spool of substrate tape from the payout chamber through the PLD chamber and into the take up spool chamber, all the while riding on idlers;    heating the buffered tape to a deposition temperature between about 600° C. and about 950° C.;    setting the oxygen pressure of the deposition chamber to between about 50 and about 1000 mTorr;    engaging the motors controlling the payout spool and the take-up spool to translate the substrate tape through the deposition chamber;    activating the target manipulator;    activating the at least one laser to form at least one laser beam, and focusing the at least one laser beam to have a laser energy density between one and six J/cm 2  such that multiple instantiations of the laser beam simultaneously impinge on multiple instantiations of the target mounted onto the target manipulator, resulting in the creation of multiple instantiations of a plume of vaporized target that slightly overlap;    depositing vaporized target onto the translating substrate by translating the substrate through the deposition zone; and    collecting the coated substrate on at the least one take up spool.    
   
   
       11 . The method of  claim 10  wherein the substrate heater is a multizone heater.  
   
   
       12 . The method of  claim 10  wherein at least two laser beams are formed.  
   
   
       13 . The method of  claim 10  wherein the target manipulator holds multiple targets.  
   
   
       14 . The method of  claim 10  wherein the spool chambers are sized to accommodate from about 2 to about 12 spools of substrate tape.  
   
   
       15 . The method of  claim 10  wherein there are at least two laser beams and each laser beam is produced by a different laser.  
   
   
       16 . The method of  claim 10  wherein the multizone heater comprises three zones.  
   
   
       17 . The method of  claim 10  wherein the buffered tape is heated to a deposition temperature between about 750° C. and about 830° C.  
   
   
       18 . The method of  claim 10  wherein the oxygen pressure in the deposition chamber is set to about 200 mTorr.  
   
   
       19 . The method of  claim 16  wherein the multizone heater heats by a combination of conductive and radiative heat transfer.  
   
   
       20 . The method of  claim 10  wherein the substrate is maintained in contact with a susceptor as it translates through the deposition zone.  
   
   
       21 . The method of  claim 20  wherein the susceptor which is maintained in contact with the susceptor as it translates through the deposition zone is transversely concavely curved and has a radius of from about 5 to about 10 meters.