Plasma treatment improves organic memory performance

A group, led by Takhee Lee from Korea’s Gwangju Institute of Science and Technology, has demonstrated a combination of materials and processing for a resistive memory circuit design.

In its current early stage of development, digital memory circuits that use organic elements instead of silicon or other inorganic materials have a list of variables and options to consider, test and optimise.

While organic electronics have potential for flexible substrates, many design aspects that are taken for granted in the silicon-circuit world must be examined.

With a specific composite polymer located between two aluminium contacts as their on/off memory element, the scientists showed that exposing the contacts to an oxygen plasma for 10 min prior to constructing the memory cell improved the ratio of on-to-off signal more than 10 fold, to more than 10,000. A larger ratio enables higher circuit performance.

In addition to the on/off ratio, other qualities such as switching speed and endurance, data retention and environmental durability must also be investigated and improved before organic memory chips would become practical. Different organic materials may also require their own solutions as well, according to Byungjin Cho, author of the technical report ‘Electrical characterisation of organic resistive memory with interfacial oxide layers formed by O₂ plasma treatment’ with Sunghoon Song, Yongsung Ji and Takhee Lee, published in the journal Applied Physics Letters.