Achieving High Yield of Perpendicular SOT-MTJ Manufactured on 300 mm Wafers

• Published in: IEEE electron device letters 2024-11, Vol.45 (11), p.2094-2097
• Main Authors: Yang, Wenlong, Ji, Zhenghui, Gao, Yang, Zhou, Kaiyuan, Guo, Qijun, Zeng, Dinggui, Wang, Shasha, Wang, Ming, Shen, Lijie, Chen, Guilin, Sun, Yihui, Liu, Enlong, He, Shikun
• Format: Article
• Language: English
• Subjects: 300 mm wafer platform; Etching; high yield; ion beam etch; Magnetic tunneling; Metals; Optical switches; Performance evaluation; Semiconductor device reliability; SOT-MRAM; Switching circuits
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2024.3454609

The large-scale fabrication of three-terminal magnetic tunnel junctions (MTJs) with high yield is becoming increasingly crucial, especially with the growing interest in spin-orbit torque (SOT) magnetic random access memory (MRAM) as the next generation of MRAM technology. To achieve high yield and consistent device performance in MTJs with perpendicular magnetic anisotropy, an integration flow has been developed that incorporates special MTJ etching technique and other CMOS-compatible processes on a 300 mm wafer manufacturing platform. Systematic studies have been conducted on device performance and statistical uniformity, encompassing magnetic properties, electrical switching behavior, and reliability. Achievements include a switching current of 680~\mu A at 2 ns, a TMR as high as 119%, ultra-high endurance (over 10^{{12}} cycles), and excellent uniformity in the fabricated SOT-MTJ devices, with a yield of up to 99.6%. The proposed integration process, featuring high yield, is anticipated to streamline the mass production of SOT-MRAM.