Nanomechanical Properties of ALD Hafnium Oxide (HfO2) on Silicon-on-Insulator (SOI) and Strained Silicon-on-Insulator (sSOI) Films

Abstract

Hafnium oxide is used as replacement for silicon oxide as a gate insulator in field-effect transistors [1]. HfO2 is used as a high-κ dielectric in DRAM capacitors and in advanced metal-oxide-semiconductor FET devices and in optical coatings [2]. Thin films of hafnium oxide (HfO2) were deposited by atomic layer deposition (ALD) on silicon-on-insulator (SOI) and benchmarked against strained-silicon-on-insulator (sSOI). Both types of films have been tested for surface morphology, crystal structure and nanomechanical properties. The nanomechanical properties have been tested using a nanoindenter from Keysight equipped with a three sided Berkovich diamond tip. The crystalline structure has been verified using X-ray diffraction. The surface morphology has been examined using atomic force microscopy (AFM) and the film thickness was verified using field emission scanning electron microscopy (FE-SEM) as indicated by the cross-sectional FE-SEM image as shown in Figure 1. We will discuss the structural and mechanical properties of the films citing the superiority of the ALD technique that is particularly used in the fabrication of the films that are presented in this study. References Intel (11 November 2007). "Intel's Fundamental Advance in Transistor Design Extends Moore's Law, Computing Performance".Zhu, C. Tang, L. R. C. Fonseca, and R. Ramprasad 47, 7399 (2012). Figure 1