Reduced activation energy of nano size phase formation in yttria stabilized zirconia film obtained by RF magnetron sputtering: Preliminary results

J T Shilo,M Sinder,J Pelleg

doi:10.1063/1.5051739

J T Shilo, M Sinder + Show 1 more

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https://doi.org/10.1063/1.5051739

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Journal: AIP Advances	Publication Date: Nov 1, 2018
Citations: 1	License type: cc-by

Affiliation: Ben-Gurion University of the Negev

Abstract

Yttria stabilized zirconia (YSZ) is a well-known ceramic material used for many various applications including a buffer layer for growth of functional oxide thin films on Si in semiconducting silicon chip technology. In the present work, YSZ thin film deposition on Si (100) substrate using magnetron sputtering system at room temperature is considered. The films were characterized by several methods: X-ray Photoelectron Spectroscopy (XPS), High Resolution Scanning Electron Microscopy (HRSEM) and X-ray diffraction (XRD). They were used in order to get information regarding the composition and the uniformity of the samples, determine their crystal structure and measure the grain size and the thin films thicknesses, respectively. In addition, the kinetics of the YSZ phase growth was investigated. Several samples were heat treated for one hour in air at various temperatures in the 500-650 °C temperature range, which made it possible to estimate the apparent activation energy of the process. The thin film characterization by XPS showed uniformity in composition through the entire depth of the film. This composition complies with the composition of 8YSZ known in the literature. This was expected since the sputtering target was 8YSZ. A decrease in film thickness and of the crystallization process was observed by XRD and HRSEM. The growth of the YSZ phase and its formation kinetics showed very low activation energy of ∼ 10.6 – 13.5 kJ/mol.

Highlights

Yttria stabilized zirconia (YSZ) is a well-known ceramic material used for various applications such as a solid electrolyte in gas sensors and fuel cells, and as a buffer layer in silicon chip technology.[1]
We study the kinetics of YSZ phase thin film growth on silicon substrate with nano scale structure by thermal annealing in air, which was prepared by Radio Frequency (RF) magnetron sputter deposition
Instead of essential difference in geometry of our nano size dense columns morphology and free standing nano grains,[9,10,11] and various temperature ranges of the investigations, it must be noted that close values of activation energies of nano YSZ phase growth give reason to assume similar phase growth mechanisms connected with high concentration of oxygen vacancies

Summary

INTRODUCTION

YSZ is a well-known ceramic material used for various applications such as a solid electrolyte in gas sensors and fuel cells, and as a buffer layer in silicon chip technology.[1] It is found that the nanocrystalline YSZ powder exhibits superior mechanical, electrical, and thermal properties as compared to its conventional coarse-grained material.[2,3,4,5,6,7,8] In particular, it is recognized that the kinetics of the YSZ nanocrystalline powder phase growth may be characterized by a very low activation energy value as compared to its micro-grained counterpart.[9,10,11] Investigation of the growth of the YSZ buffer layer on silicon by sputter deposition technique reveals a nano scale structure, which displays characteristics in accordance with the sputtering zone model[12] (See for example Ref. 13). Our preliminary results show that the kinetics is characterized by a very low activation energy of ∼ 10.6 – 13.5 kJ/mol

EXPERIMENTAL

RESULTS

DISCUSSION

SUMMARY