Combinatorial study of Ag-Te thin films and their application as cation supply layer in CBRAM cells

In this work, we investigate binary Ag-Te thin films and their functionality as a cation supply layer in conductive bridge random access memory devices. A combinatorial sputter deposition technique is used to deposit a graded AgxTe1-x (0 < x < 1) layer with varying composition as a function of the position on the substrate. The crystallinity, surface morphology, and material stability under thermal treatment as a function of the composition of the material are investigated. From this screening, a narrow composition range between 33 and 38 at% Te is selected which shows a good morphology and a high melting temperature. Functionality of a single Ag2-delta Te composition as cation supply layer in CBRAM with dedicated Al2O3 switching layer is then investigated by implementing it in 580 mu m diameter dot Pt/Ag2-delta Te/Al2O3/Si cells. Switching properties are investigated and compared to cells with a pure Ag cation supply layer. An improved cycling behavior is observed when Te is added compared to pure Ag, which we relate to the ionic conducting properties of Ag-Te and the preferred formation of AgTe phases