Sensor-based MOCVD for the growth of low surface resistance YBCO on MgO enabling Q´s in excess of 100000

Today MOCVD, due to its inherent advantages such as scaleability and throughput, is the growth technique of choice for many compound semiconductors as a production method. However, the use of MOCVD to deposit high quality HTS material has been impeded by the lack of stable precursors. To overcome the problems of limited process reproducibility caused by these shortcomings, real time control of the gas phase composition by ultraviolet absorption sensors has been utilized. This technique allows for a very tight control of the composition of the deposited material. A surface resistance R/sub s/ lower than 250 /spl mu//spl Omega/ (77 K, scaled to 10 GHz) could be measured on 700 nm thick MOCVD YBCO films. This value correlates very well with the surface resistance extracted from measurements of the quality factor Q/sub 0/ of a simple microstrip resonator used as a process control monitor. Consistent surface resistance values below 350 /spl mu//spl Omega/ prove the reproducibility of the sensor based MOCVD approach. For cellular telecommunication devices at 845 MHz quality factors Q/sub 0/ in excess of 100,000 at 77 K are indicative of the excellent material quality.