Progress in High Throughput Processing of Long-Length, High Quality, and Low Cost IBAD MgO Buffer Tapes at SuperPower

High rate reactive magnetron sputtering at transition mode were developed to deposit Al₂O₃ and Y₂O₃ layers at a routine production speed of 750 m/h (all speeds in this paper are the equivalent speed of 4 mm wide tape.) with excellent process stability over kilometer length and from run to run, and with same texture and critical current as our previous ion beam sputtering process. For the IBAD MgO process, a reactive ion beam sputtering process with higher deposition rate and long time stability has been developed and routine production speed has been increased to 360 m/h. The tape driving system has been upgraded from 6 wraps to 11 wraps in our Pilot Buffer system. Homo-epitaxial MgO process has been re-tuned with the routine production speed increased to 340 m/h. The LaMnO₃ routine process speed has been increased to 450 m/h by reactive sputtering of a La-Mn alloy target. Throughput was further improved by reducing total buffer process from 5 steps to 3 steps. The routine processing length of single pieces of buffer tape was increased to 1,400 m. The actual production capacity is 500 km/year now. We developed a new Direct LMO process with same I_c as our standard IBAD buffer stack and dramatically increased the yield which makes it a very promising manufacturing process.