Selective Deposition of C-axis Oriented Pb_5Ge_3O_(11) on the Patterned High k Gate Oxide by MOCVD Processes

摘要

For the high density FeRAM applications, the integration process-induces damages such as etching damage that degrades the properties of FRAM devices and the high surface roughness of ferroelectric thin film that results in the difficulty for alignment are critical issues. In order to solve these problems, selective deposition process is developed to simplify the integration processes and improve the properties of FeRAM memory devices. Based on the differential deposition rates of ferroelectric materials on high-k oxide and silicon dioxide, we can selectively deposit a c-axis oriented PGO thin film on the patterned high-k oxide such as ZrO_x (x=0-2), HfO_x (x=0-2), TiO_2, and their mixtures other than on SiO_2. By patterning the high-k dielectric, the PGO deposition is limited to just the preferred pattern high-k area. SEM, EDX and x-ray measurements further confirm that the c-axis oriented PGO thin films are selectively deposited on the high-k gate oxide other than on the field SiO_2 including alignment mark area, which will eliminate the roughness problem for the alignments. Also the etching damage is eliminated since there is no need to etch the PGO film, which improved the properties of FeRAM devices.