Fabrication and thermal-chemical stability of magnetoresistive random-access memory cells using /spl alpha/-Fe/sub 2/O/sub 3/ bottom spin valves

This paper discusses fabrication, stability and device characteristics of Si//spl alpha/-Fe/sub 2/O/sub 3/ (25 nm)/Co (3 nm)/Cu (2.3 nm)/Co (3.1 nm)Ta/sub 2/O/sub 5/ (2.5 nm) giant magnetoresistance (GMR) spin-valve magnetoresistive random-access memory (MRAM) cells 6 /spl mu/m wide and 18 /spl mu/m long dimension. Fabricated single-bit and 3/spl times/3-bit MRAM cells had very good GMR performance for MRAM characteristics and excellent endurance in undergoing standard high-temperature semiconductor processes. The high thermal, and chemical stability of /spl alpha/-Fe/sub 2/O/sub 3/ bottom GMR spin valves is mainly attributed to the good thermal stability associated with the high blocking temperature (about 390/spl deg/C) and the good corrosion resistance of the /spl alpha/-Fe/sub 2/O/sub 3/ antiferromagnetic material. In this paper, models for an individual /spl alpha/-Fe/sub 2/O/sub 3/ bottom GMR spin-valve MRAM cell using SPICE device model elements are introduced for the first time. The SPICE model is useful for predicting the MRAM device characteristics related to the speed and power dissipation in different MRAM bit arrays and under various operating conditions.