The objective of this thesis is to explore novel Threshold Switching Selector (TSS) materials for emerging MRAM (Magnetic Random-Access Memory) technologies. A selector serves as a simple two-terminal device, behaving like a switch or a diode that turns on above a certain voltage and stays off otherwise. When combined to a memory element, it prevents sneak current in non-selected memory cells, enabling denser memories. In addition, TSS aims at replacing the selection transistor and at reducing the number of vias to connect with the CMOS, thus saving power and surface area.
To achieve TSS compatible with MRAM, it is critical to develop new selectors materials that match the characteristics of magnetic tunnel junction (MTJ). For example, Ovonic threshold switch (OTS) used with phase change PC-RAM (in production) has a threshold voltage larger than 2V. This voltage is too high for MTJs that must be operated below 1V to avoid degrading the MgO tunnel barrier.