Magnetic and Writing Properties of Clad Lines Used in a Toggle MRAM

We fabricated toggle magnetic random access memories with clad writing lines. First, we evaluated the structures and magnetic properties of sputter-deposited cladding layers. The substrate bias during the deposition affected not only the sidewall coverage, but also the crystallinity and magnetic properties of the cladding. The optimized clad lines reduced the writing current to as low as 50% of that of unclad lines. Moreover, the writing current deviation divided by the average current of magnetic tunnel junction cells with clad lines was as low as that with unclad lines. Using the optimized clad lines, we constructed memory arrays with a large operating margin and reduced switching current