Choosing the best combination of SBT precursors
Metal Organic Chemical Vapor Deposition (MOCVD) is a process by which semiconductors are constructed. A number of different organic metal building blocks exist; the key is finding the right combination. Experts at the Universita di Catania in Italy tackled this issue for SrBi2Ta2O9, more commonly referred to as SBT. Seven different organic metal precursors, four strontium (Sr), two bismuth (Bi) and one tantalum (Ta), were investigated in the Italian laboratory. The conditions under which MOCVD takes place can dramatically affect the outcome, specifically the temperature and the amount of oxygen present. It was found that the fluorinated strontium precursors outperformed the non-fluorinated precursors. Some contamination was identified, but easily removed during annealing. Another useful discovery was that raising the temperature at which MOCVD takes place improved the amount of mass transport for one of the Bi precursors. The most robust trio of precursors turned out to be Sr(tmhd)2pmdeta, Bi(tmhd)3 and Ta (OC2H5)5. Armed with the results from the laboratory experiments, semiconductor manufacturers can select the ideal combination of SBT precursors according to their needs. The result is expected to contribute to industries reliant upon Non-Volatile Memory (NVM), such as smart cards and RFID technology. The Universita di Catania scientists are looking to exploit the knowledge acquired during the project.
