RF Sputtering, Post-Annealing Treatment and Characterizations of ZnO (002) Thin Films on 3C-SiC (111)/Si (111) Substrates

Visakh Valliyil Sasi,Abid Iqbal,Faisal Mohd-Yasin,Kien Chaik,Alan Iacopi

doi:10.3390/mi8050148

Abstract

We report on the radio frequency (RF) sputtering of c-axis oriented ZnO thin films on top of epitaxial 3C-SiC-on-Si (111) substrates, which were then subjected to post-annealing treatment at 400, 600 and 800 °C. Grazing incident X-ray Diffraction (XRD) data show that the Full Width Half Maximum (FWHM) values for O2/Ar ratios between 30% and 60% are consistent, with a mean of 0.325° and a standard deviation of 0.03°. This is largely attributed to the smaller lattice mismatch of 5% between the ZnO (002) and SiC (111) films. The quality of the ZnO films deteriorated at the post-annealing treatment of 800 °C, as demonstrated by the increasing value of FWHM diffraction peaks, the reducing value of the peak intensity, the reducing percentage of (002) oriented area under the curve, and the increasing value of biaxial stress. We propose a simple growth model to explain the result.

Highlights

Zinc oxide (ZnO) is a group II-IV semiconductors, which is suitable for a wide range of scientific and technological applications
In a subsequent work from the same group [13], they fabricated ZnO-based surface acoustic wave (SAW) resonators on top of Si (100) and 3C-SiC/Si (100) substrates. They reported improved insertion loss and temperature stability of the resonator made on top of the 3C-SiC (111) buffer layer. Both Sha et al and Phan et al demonstrated that ZnO thin film with dominant (002) orientation could be sputtered on top of Si substrate with a polycrystalline 3C-SiC buffer layer
We have demonstrated the radio frequency (RF) sputtering of c-axis oriented ZnO thin films on top of epitaxial 3C-SiC-on-Si (111) substrates

Summary

Introduction

Zinc oxide (ZnO) is a group II-IV semiconductors, which is suitable for a wide range of scientific and technological applications. They observed a dominant (002) orientation using RF sputtering They reported FWHM diffraction peak values of 0.2107◦ and 0.3498◦, respectively, for both methods at the annealing temperature of 800 ◦C. In a subsequent work from the same group [13], they fabricated ZnO-based SAW resonators on top of Si (100) and 3C-SiC/Si (100) substrates They reported improved insertion loss and temperature stability of the resonator made on top of the 3C-SiC (111) buffer layer. Both Sha et al and Phan et al demonstrated that ZnO thin film with dominant (002) orientation could be sputtered on top of Si substrate with a polycrystalline 3C-SiC buffer layer. The results for the latter were recently reported in [14]

Experimental Methods

33. RReessuullttssaanndd DDiissccuussssiioonn

Findings

Conclusions