Currently, major semiconductor R&D institutions and companies around the world have been doing a lot of work on SOT-MRAM etching process, however, the etching process of SOT-MRAM is still an important technical challenge for the industry.

Recently, the Institute of Microelectronics, Chinese Academy of Sciences has made new progress in the field of SOT-MRAM key integration technology.

According to "Institute of Microelectronics, Chinese Academy of Sciences", in order to better solve the problem of SOT-MRAM etching technology to achieve high-density on-chip integration of SOT-MRAM, and to study the impact of different etching processes on the magnetoelectric properties of the device, Luo Jun, a researcher at the Center for Integrated Circuit Pilot Process Research and Development, Institute of Microelectronics, Chinese Academy of Sciences The group has developed an etching "Stop MgO" process (SOMP-MTJ) based on perpendicular magnetic anisotropy SOT-MTJ, which effectively solves the problem of etched short circuit in SOT-MRAM fabrication.

According to the news, the group developed an etching "stop MgO" process that stops the MTJ etching endpoint precisely at the ~1 nm thick MgO layer (Figure 1c,d). Since the sidewalls of the MgO tunneling layer are never exposed, short-circuiting of the MgO layer is avoided. The SOT-MTJ device arrays prepared by the "stop MgO" etching process can improve the resistive yield of the wafers to 100%, and also improve the uniformity of key parameters such as TMR, resistance, and coercivity of the devices (Figure 2a,b).



In addition, the "stopped MgO" devices have higher thermal stability, lower flip current density, and flip speed up to 1 ns (Fig. 2c,d). The research results provide a key solution to the problem of high speed, low power consumption and high integration SOT-MRAM etching technology.