Direct electrical characterization of embedded ferroelectric lead titanate nanoislands

Abstract

We report on the fabrication and characterization of lead titanate nanoislands on platinized silicon substrates embedded into a low-k dielectric. Our findings with Pt and Au as collective top electrodes are compared to previous results and thin films, and we discuss the coercive field and the remanent polarization with special care devoted to capacitive and leakage contributions of the nonpolar matrix. A direct electrical characterization of sub-100-nm ferroelectric nanoislands becomes feasible if they are measured in parallel, providing that the thin film material parameters of both ferroelectric and spin-on glass are independently determined.

Switching Current Measurements of Self-Assembled Ferroelectric PbTiO3 Nanoislands Using Scanning Probe Microscopy

“…Nanosized ferroelectrics, such as nanoislands, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] ultrathin films, [19][20][21] nanorods, [22][23][24][25] and nanotubes, 26,27) have recently attracted significant attention from the viewpoint of practical applications as well as for studying the basic physics of ferroelectrics. One important issue that needs to be addressed in nanosized ferroelectrics is the change in their spontaneous polarization upon downscaling their physical dimensions since the polarization is the primary order parameter in ferroelectrics.…”

“…In particular, a decrease in the amount of charge transferred by polarization switching crucially increases the difficulty in measuring spontaneous polarization of nanosized ferroelectrics, because the absolute amount of charge decreases in proportion to the square of lateral dimensions. Therefore, there have been very few reports on polarization hysteresis loops or switching currents for nanosized ferroelectrics, 5,8,15,16) whereas piezoelectric coefficients, which are expected to be proportional to the polarization, and their size dependence have been extensively studied. 4,6,13,17,18) This is also because the piezoelectric displacement is in principle independent of the lateral dimensions of the ferroelectrics.…”

Size Dependence of Ferroelectric Polarization in PbTiO3 Nanoislands

“…Nanosized ferroelectrics, such as nanoislands, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] ultrathin films, [21][22][23][24][25][26][27][28][29][30] nanorods, [31][32][33][34] and nanotubes, 35,36) have recently attracted significant attention from the viewpoint of practical applications as well as for studying the basic physics of ferroelectrics. One important issue that needs to be addressed in nanosized ferroelectrics is the change in their spontaneous polarization on downscaling their physical dimensions.…”

“…Until now, there have been very few reports on polarization hysteresis loop or switching current measurements in nanosized ferroelectrics. 5,9,17,18,41) Clemens and coworkers integrated ferroelectric PbTiO 3 nanoislands in an insulating hydrogen silsesquixane film and achieved electrical access to the PbTiO 3 grain tops by preparing collective Au or Pt top electrodes with diameters of 75 m after surface polishing. 17,18) Although they successfully obtained currentvoltage (I-V ) hysteresis loops, the ferroelectric polarization was not quantified probably because of difficulty in estimating how many nanoislands were there in an electrical contact with the top electrodes.…”

“…5,9,17,18,41) Clemens and coworkers integrated ferroelectric PbTiO 3 nanoislands in an insulating hydrogen silsesquixane film and achieved electrical access to the PbTiO 3 grain tops by preparing collective Au or Pt top electrodes with diameters of 75 m after surface polishing. 17,18) Although they successfully obtained currentvoltage (I-V ) hysteresis loops, the ferroelectric polarization was not quantified probably because of difficulty in estimating how many nanoislands were there in an electrical contact with the top electrodes. In our previous study, switching current measurements of ferroelectric PbTiO 3 nanoislands were demonstrated by atomic force microscopy (AFM) using a blunt tip with a flat end-face as a top electrode.…”