MagPDK: An open-source process design kit for circuit design with magnetic tunnel junctions

In this paper, we introduce MagPDK, an open-source process design kit that represents a magnetic tunnel junction fabrication process. Based on the widely known open design kit FreePDK, MagPDK extends it by adding magnetic tunnel junction devices on top of the standard CMOS transistors. The core of this design kit includes physical design verification rules, connectivity and parasitic extraction decks and a set of parametric cells representing variations of the MTJ device. Electrical simulations can be performed by integrating MagPDK with external MTJ compact models. For this purpose, wrappers are provided for three open-source models available in the literature. A basic set of non-volatile standard-cells and memory bit-cells is supplied with the package to illustrate its capabilities. All of the elements in the PDK were developed using de-facto standard formats, such as OpenAccess, LEF and Spice, and can be seamlessly employed within industry-standard digital, analog or mixed-signal design flows. In addition, MagPDK is backward-compatible with any FreePDK-based layout. With MagPDK, which is the only open-source design kit for magnetic processes available to date, we provide a common environment for researchers, circuit designers and EDA developers, so that they can explore the MTJ-based circuit design space not only in the behavioral level, but in the physical implementation level as well.