Intrinsic stress dependence of Pt hillock formation and its related electrical properties of SBT capacitor

Abstract

1999) Intrinsic stress dependence of Pt hillock formation and its related electrical properties of SBT capacitor, The P f l i electrode stacks were deposited on the SiOxiSi substrate by DC magnetron sputtering. The Pt layers were deposited at various temperature of RT-500"C. These electrode stacks were annealed at 6 5 0 T for 30min in O2 ambient. A lot of high hillocks were observed on the Pt surface deposited at low temperatures (RT-300°C) after the anneal process. But the hillocks were decreased in both number and height with increasing the deposition temperature of the Pt layer. We found in both SEM inspection and stress measurement that the deposition temperature dependence of the Pt hillock formation could be explained by the difference in the intrinsic stress generated during deposition process. We also demonstrated the effect of Pt hillocks on electrical properties of SBT capacitor. The 2Pr values of the SBT capacitors were about 13p C/cm2 regardless of the Pt deposition temperatures. But the short probabilities were decreased with the increase of the Pt deposition temperatures. This result is well consistent with the trend of Pt hillock formation.

Platinum (100) Hillock Growth in Pt/Ti Electrode Stack for SrBi2Ta2O9 Ferroelectric Random Access Memory

“…Pt hillocks are a major * To whom all correspondence should be addressed. E-mail: cww2000@kaist.ac.kr concern because they can lead to capacitor shorts, as reported previously [4,5]. It has been reported that hillock formation depends strongly on the compressive stress generated during both sample preparation and post-annealing [6,7] and that the main mass transport mechanism for the growth of the hillock on the thin film with a columnar structure is the grain boundary diffusion [8,9].…”

“…It has been reported that hillock formation depends strongly on the compressive stress generated during both sample preparation and post-annealing [6,7] and that the main mass transport mechanism for the growth of the hillock on the thin film with a columnar structure is the grain boundary diffusion [8,9]. Three factors are considered in the total compressive stress of the Pt/Ti electrode stack: intrinsic stress, thermal stress, and extrinsic stress [4,5].…”

Annealing effect of platinum-based electrodes on physical properties of PZT thin films

“…Hillocks began to appear on the surface at 700°C, continuing the growth process as the temperature was increased to 800°C. Researchers have reported that hillock formation plays a role the internal stress of the Pt layer during annealing [7][8][9][10]. In Fig.…”

“…Pt hillocks are a major concern because they can lead to capacitor failure [6]. In addition, there is also a possibility that inter-diffusion between each layer creates a Pt-Ti compound, which can alter the crystal structure of the bottom electrode, affecting the orientation and crystal structure of the ferroelectric materials [7,8].…”

Investigations on the high temperature compatibility of various adhesion layers for platinum

“…They showed that Pt thin film deposited at room temperature has a high compressive stress and thus the hillock amount is high. In contrast, the Pt film deposited at 500°C shows strong tensile stress and thus the hillock formation is disappeared[7].…”