Development of stable PZT sputtering process using ex-situ crystallization and PZT/Pt interface control technique

Precise control of Pb content in sputter-deposited amorphous PZT films was achieved by optimization of substrate temperature; substrate and shield potential, sputtering condition, and target surface condition. Pb, Ti and oxygen at PZT/Pt interfaces have important roles in amorphous-perovskite phase transformation and their effects were used in seeding techniques. A variety of grain sizes and <111> preferred orientation was obtained by 2 step depositions using Ti seed layers and initial Ar/O/sub 2/ sputter-deposited seed layers. 2Pr of 40 uC/cm/sup 2/ was obtained over 6" Si substrates. Differences in amorphous structure were found important in PZT crystallization. Seeding technique and an improved sputtering system make it possible to apply the PZT sputtering technique for FeRAM fabrication. Pb behavior during crystallization and post thermal processes was analyzed and modeled to understand electrical properties.