| AVS 65th International Symposium & Exhibition | |
| Manufacturing Science and Technology Group | Tuesday Sessions |
| Session MS+MI+RM-TuM |
| Session: | IoT Session: Challenges of Neuromorphic Computing and Memristor Manufacturing (8:00-10:00 am)/Federal Funding Opportunities (11:40 am-12:20 pm) |
| Presenter: | David Hughart, Sandia National Laboratories |
| Authors: | D.R. Hughart, Sandia National Laboratories R.B. Jacobs-Gedrim, Sandia National Laboratories K.E. Knisely, Sandia National Laboratories N.J. Martinez, Sandia National Laboratories C.D. James, Sandia National Laboratories B.L. Draper, Sandia National Laboratories E.S. Bielejec, Sandia National Laboratories G. Vizkelethy, Sandia National Laboratories S. Agarwal, Sandia National Laboratories H.J. Barnaby, Arizona State University M.J. Marinella, Sandia National Laboratories |
| Correspondent: | Click to Email |
Resistive switching properties in transition metal oxides and other thin films have been an active area of research for their use in nonvolatile memory systems as Resistive Random Access Memory (ReRAM). ReRAM is a candidate for storage class memory technologies, and studies have also revealed a high degree of intrinsic radiation hardness making digital ReRAM a candidate for radiation-hardened memory applications. Analog ReRAM has also generated interest from the neuromorphic computing community for use as a weight in neural network hardware accelerators.
One of the manufacturing challenges for the valence change memory (VCM) type of ReRAM has been the development of substoichiometric switching layer films. Physical vapor deposited (PVD) substoichiometric TaOx films are an attractive option for a VCM switching layer because they are complementary-metal-oxide-silicon (CMOS) compatible and are deposited at low temperatures. However, control of the oxygen partial pressure to produce substoichiometric TaOx films cannot be directly achieved through flow control because the oxygen consumption by the Ta target and chamber surfaces is nonlinear as the chamber transitions from metal to insulator conditions. The oxygen partial pressure can be controlled using a feedback system, though feedback-assisted deposition techniques are difficult to regulate, making them ill-suited to production. One alternative to a feedback system is to deposit a higher stoichiometry TaOx film, deposited in a more stable flow-partial pressure chamber regime, and use annealing to drive Ta into the film to achieve the desired stoichiometry. Here, we compare switching layers fabricated using both techniques, and discuss the relative merits of each technique. The devices are manufactured in crossbar arrays to be testable by automatic probers, enabling the collection of large scale yield and performance data sets across process splits.
Manufacturing improvements enabled fabrication of analog ReRAM with characteristics suitable for neuromorphic computing applications. The performance of a TaOx ReRAM based hardware accelerator at image classification accuracy after training was evaluated. The classification accuracy showed little degradation in initial radiation tests, suggesting analog ReRAM may be suitable for neuromorphic computing applications in radiation environments as well.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.