US Patent 10270025 Semiconductor structure having magnetic tunneling junction (MTJ) layer

The present disclosure provides a semiconductor structure, including an Nth metal layer over a transistor region, where N is a natural number, and a bottom electrode over the Nth metal layer. The bottom electrode comprises a bottom portion having a first width, disposed in a bottom electrode via (BEVA), the first width being measured at a top surface of the BEVA, and an upper portion having a second width, disposed over the bottom portion. The semiconductor structure also includes a magnetic tunneling junction (MTJ) layer having a third width, disposed over the upper portion, a top electrode over the MTJ layer and an (N+1)th metal layer over the top electrode. The first width is greater than the third width.