Impact of Cation Vacancies on Leakage Current on TiN/ZrO2/TiN Capacitors Studied by Positron Annihilation

TiN/ZrO
2
/TiN capacitors were characterized using XRD, STEM, EDX, and monoenergetic positron beams. For an as-deposited ZrO
2
layer, an interlayer was formed in the layer. After post-deposition annealing at 550°C, the width of the interlayer expanded. The major vacancy-type defects in the ZrO
2
layer were determined to be a Zr-vacancy coupled with oxygen vacancies by the positron annihilation technique. After annealing, the size of these vacancies increased. The presence of the cation vacancies and their complexes in the ZrO
2
layer suggests that not only oxygen vacancies but also such defects play a role in the defect formation of the ZrO
2
layer and affect its electrical properties.