Atomic layer deposition and tellurization of Ge–Sb film for phase-change memory applications

Abstract

We studied the atomic layer deposition (ALD) and the tellurization of Ge–Sb films to prepare conformal crystalline Ge–Sb–Te (GST) films and to achieve void-free gap filling for emerging phase-change memory applications.

Composition control of conformal crystalline GeSbTe films by atomic layer deposition supercycles and tellurization annealing

“…For the ALD of GeSb, the times for GeCl 2 -dioxane feeding, GeCl 2 -dioxane purge, Sb(SiEt 3 ) 3 feeding, and Sb(SiEt 3 ) 3 purge were 15, 20, 15, and 15 s, based on our previous work. 21 Fig. 5 shows the results of the AES depth profile of the Ge-Sb films.…”

“…Then, the deposited films were annealed using the same method as the previous works. 21,25 Di(tert-butyl)telluride ( t Bu 2 Te) was used as a Te precursor, and the annealing temperature was set to 230 1C, as optimized in the previous work. Only the surface region was tellurized at lower temperatures.…”

“…Finally, we investigated the thickness and compositional uniformity of GST films in a HAR pattern to confirm that the process of this work is viable in 3D vertical architectures. Our previous work 21 was performed to gapfill crystalline GST thin films in confined structures and focused on demonstrating the preparation of GST films by tellurization of ALD GeSb film. On the other hand, the present work was done for applications in 3D vertical architectures and focused on composition control by introducing ALD Sb subcycles.…”

“…In a previous study, we produced fully-tellurized crystalline GST thin films by tellurization annealing ALD of GeSb films. 21 Due to the annealing at 230 °C, the GST thin film prepared in this method is expected to have a minor volume change during subsequent processing or device operation compared to the amorphous thin film prepared by the supercycle method at a low process temperature. However, the Ge-rich GST films were obtained, and the film composition was not controllable by varying the precursor feeding times as in most ALD processes.…”

Phase-Change Memory by GeSbTe Electrodeposition in Crossbar Arrays

“…Plasma sputtering has commonly been used for depositing PCMs demonstrating strong switching properties. − Atomic layer deposition (ALD) has shown good composition control over the PCM in high-aspect-ratio structures. − Other PCM deposition methods that have been explored include chemical vapor deposition. , However, there are several limitations associated with these methods. For example, sputtering deposit material at an angle making it unsuitable in filling high density or high-aspect-ratio structures.…”