Tailoring Ge Nanocrystals via Ag-Catalyzed Chemical Vapor Deposition to Enhance the Performance of Non-Volatile Memory

TL;DR

A new Ag-catalyzed CVD method is developed to create Ge nanocrystals with controlled size and density for improved non-volatile memory performance.

Contribution

An Ag-catalyzed CVD method enables precise control of Ge nanocrystal size and density for non-volatile memory applications.

Findings

Ge nanocrystals grown at 900 °C show a memory window of 7.0 V under ±8 V bias.

Devices exhibit charge retention exceeding 10 years when nanocrystals are grown at 700 °C.

Faceted Ge nanocrystals are successfully synthesized on SiO2/Si substrates using Ag-catalyzed CVD.

Abstract

With the rapid advancement in portable electronics, artificial intelligence, and the Internet of Things, there is an escalating demand for high-density, low-voltage non-volatile memory (NVM) technologies. Germanium (Ge) nanocrystals (NCs) have emerged as a promising candidate for NVM applications; however, traditional synthesis methodologies suffer from limitations in achieving precise control over the size and density of these nanocrystals, which exert a significant influence on device performance. This study presents an innovative Ag-catalyzed chemical vapor deposition (CVD) methodology for the synthesis of Ge NCs with precisely controllable size and density on SiO2/Si substrates, tailored for NVM applications. Scanning electron microscopy characterization confirms the successful growth of faceted Ge NCs. Electrical characterization of the fabricated devices reveals that Ge NCs grown at temperatures ranging from 700 to 1000 °C exhibit memory windows spanning from 3.0 to 6.8 V under a ±6 V bias. Notably, the device synthesized at 900 °C demonstrates an exceptional memory window of 7.0 V under a ±8 V bias. Furthermore, the Ge NC-based NVM devices exhibit excellent charge retention characteristics. Specifically, for the device with Ge NCs grown at 700 °C, the time required to retain charge from 100% to 95% of its initial value exceeds 10 years, demonstrating long-term stable charge storage capability. These findings underscore the significant potential of this approach for the development of high-performance NVM technologies.

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