Water-Erasable Memory Device for Security Applications Prepared by the Atomic Layer Deposition of GeO 2

We have investigated the atomic layer deposition (ALD) of GeO 2 thin films that dissolve in water rapidly and have excellent electrical properties for use in memory devices. The growth characteristics based on surface reactions during the ALD process are discussed by correlation with experimental results and atomistic theoretical calculation. Compared to sputtered GeO 2 films, the ALD-grown GeO 2 is perfect, pure, and water-soluble at room temperature and has better electrical properties for use as the dielectric layer in memory devices. The superior film properties of ALD GeO 2 are attributed to the higher film density, high purity, low roughness, and highly stoichiometric film composition. Finally, we demonstrate the fabrication of charge-trapping memory (CTM) devices with ALD GeO 2, and that the electrical information stored in the CTM can be eliminated immediately by exposure to one droplet of water at room temperature. Thus, ALD GeO 2 could find widespread application in the fabrication of secure memory devices.