Germanium Segregation in CVD Grown Sige Layers for Flash Memory Application

TL;DR

This study demonstrates the formation of crystalline germanium nanodots in SiO2 via CVD and thermal processes, showing potential for charge storage in flash memory applications.

Contribution

It introduces a method to create high-density Ge nanodots in SiO2 with structural and electrical characterization, advancing memory device technology.

Findings

High-density Ge nanodots formed by oxidation-induced segregation.

Nanodots located approximately 5 nm from substrate.

Evidence of charge storage via hysteresis in CV curves.

Abstract

A 2D layer of spherical, crystalline Ge nanodots embedded in SiO2 was formed by low pressure chemical vapour deposition combined with furnace oxidation and rapid thermal annealing. The samples were characterized structurally by using transmission electron microscopy and rutherford back scattering spectrometry, as well as electrically by measuring CV and IV characteristics. It was found that formation of a high density Ge dots took place due to oxidation induced Ge segregation. The dots are situated in the SiO2 on the average distance 5 nm from the substrate. Strong evidence of charge storage effect in the crystalline Ge nanodot layer is demonstrated by the hysteresis behavior of the high frequency CV curves.