With Si substrate, Ge-based nonvolatile memory devices with the charge trapping layer and tunnel dielectric respectively formed by a Ge-stabilized tetragonal ZrO2 film and a thermal GeO2 film are explored in this work. A 1.8-V memory window is achieved by program/erase (P/E) at +/- 5 V for 1 ms which proves high-speed/low-voltage operation and this desirable characteristic is mainly due to the crystalline ZrO2 trapping layer which provides a high permittivity of 36.8 with a large amount of trapping sites. A negligible degradation of memory window up to 10(5) P/E cycles can be accomplished by applying gate pulse of +/- 5 V for 1 ms and it demonstrates that the thermal GeO2 film is robust enough to offer the required reliability. Good retention characteristics with 70% charge after a 10 year operation at 85 degrees C also affirm the eligibility of GeO2 as the tunnel dielectric. These results suggest that this novel device structure holds great potential for future high-performance memory. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3547717] All rights reserved.