Carbon doping can help make reliable, next generation memory devices

What is it about?

Phase change memory (PCM) technology uses materials that can change phases to store data. One such material of interest is Ge2Sb2Te5 (GST). It is stable at room temperature and can quickly switch between an amorphous phase and a face centered cubic (fcc) phase. In the amorphous phase, GST has high electrical resistance. In the fcc phase, it has low resistance. At high temperatures, however, the fcc phase of GST changes to a hexagonal structure. This is problematic as GST cannot be transformed back to the high resistance state. If carbon atoms are added to GST, they can raise the phase transition temperature and avoid this change. This study aims to understand how carbon atoms affect the atomic level structure of GST. To observe these changes, the authors used techniques like xray diffraction and transmission electron microscopy. They found that carbon doping makes the material more stable by controlling the nucleation and crystallization processes. Carbon atoms also refined the size of the grains, further adding to the stability of GST.

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Photo by Markus Spiske on Unsplash

Photo by Markus Spiske on Unsplash

Why is it important?

PCM is seen as the future of data storage. It can be used to store data even with the power turned off. But the undesired transformation of GST poses a challenge. It means that at high temperatures, PCM devices that use GST would find it difficult to keep stored data intact. The results of this study, however, provide options to stabilize GST. These insights can pave the way for developing more reliable PCM devices. KEY TAKEAWAY: The challenge in PCM is making sure that the data stored in the device remains intact during operation, when the temperature rises. This study helps provide a solution for the same. It could lead to novel PCM devices for commercial use.