Characterization of Strain Induced by PECVD Silicon Nitride Films in Transistor Channel

In order to reach high level of transistor performances, it is desirable to increase electrical conductivity of the device. An efficient way to enhance carrier mobility in conduction channel is to generate strain in the structure induced by process. To achieve that, stress engineering of the contact etch stop layer (CESL), an amorphous hydrogenated silicon nitride film deposited by plasma enhanced chemical vapour deposition on top of the metal oxide semiconductor assembly, is widely used since it is a low-cost technique. Indeed, this film possesses an intrinsic stress that can be set from tensile (σ=1.6GPa) to compressive (σ=-3.0GPa) depending on deposition conditions.