R&D: Density of Amorphous Sputtered Ge2Sb2Te5 Thin Films

AIP Advances has published an article written by Q. Zhang, C. Lian, Q. Xu, Y. Yu, and M. Skowronski, Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.

Abstract: “The density, crystallinity, and microstructure of reactively sputtered amorphous Ge₂Sb₂Te₅ thin films have been assessed as a function of deposition temperature. The continuous density increase was observed with increasing substrate temperature between room temperature and 200 °C. The films deposited at room temperature are amorphous and exhibit a columnar structure with a lateral size of cells in the 10–15nm range. Cells consist of high-density interior with boundaries with the density lower by ∼9% due to incorporation of pores. The pores and the columnar microstructure can be eliminated by deposition at 80 °C while still preserving the amorphous phase. The density of pore- and stress-free amorphous Ge₂Sb₂Te₅ is 6.16 g/cm³ and is only 1.5% lower than the crystalline Ge₂Sb₂Te₅ with NaCl structure.“

This work was supported in part by the Intel Corporation and Data Storage Systems Center at Carnegie Mellon University. The authors gratefully acknowledge the support of the Materials Characterization Lab Facilities at Carnegie Mellon University under Grant No. MCF-677785.