Magnetic tunnel junction encapsulation using hydrogenated amorphous semiconductor material

Abstract

Embodiments are directed to an electromagnetic memory device having a memory cell and an encapsulation layer formed over the memory cell. The memory cell may include a magnetic tunnel junction (MTJ), and the encapsulation layer may be formed from a layer of hydrogenated amorphous silicon. Amorphous silicon improves the coercivity of the MTJ but by itself is conductive. Adding hydrogen to amorphous silicon passivates dangling bonds of the amorphous silicon, thereby reducing the ability of the resulting hydrogenated amorphous silicon layer to provide a parasitic current path to the MTJ. The hydrogenated amorphous silicon layer may be formed using a plasma-enhanced chemical vapor deposition, which can be tuned to enable a hydrogen level of approximately 10 to approximately 20 percent. By keeping subsequent processing operations at or below about 400 Celsius, the resulting layer of hydrogenated amorphous silicon can maintain its hydrogen level of approximately 10 to 20 percent.