Chemical Vapor Deposition of Germanium Nanocrystals on Hafnium Oxide for Non-Volatile Memory Applications

Abstract

ABSTRACTIn this paper, we investigate the chemical vapor deposition (CVD) of Ge nanocrystals (NCs) directly on hafnium oxide HfO2 dielectric for non-volatile memory applications. Germane GeH4 was used as a precursor. Atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to characterize the Ge NCs. The dependence of the Ge NC size and density on the deposition temperature, deposition time, and flow rate was explored. A high Ge NC density of 1011 cm-2 was obtained at a deposition temperature of 600°C, with a mean diameter of about 16 nm. MOS capacitors with CVD Ge NCs embedded in the HfO2 gate dielectric were fabricated. Hysteresis of capacitance-voltage (C-V) characteristics of capacitors with Ge NCs was observed, demonstrating memory effect.