Dielectric Properties of Thermal and Plasma-Assisted Atomic Layer Deposited Al[sub 2]O[sub 3] Thin Films

A comparative electrical characterization study of aluminum oxide deposited by thermal and plasma-assisted atomic layer depositions (ALDs) in a single reactor is presented. Capacitance and leakage current measurements show that the deposited by the plasma-assisted ALD shows excellent dielectric properties, such as better interfaces with silicon, lower oxide trap charges, higher tunnel barrier with aluminum electrode, and better dielectric permittivity , than the thermal ALD . Remarkably, the plasma-assisted ALD films exhibit more negative fixed oxide charge density than the thermal ALD layers. In addition, it is shown that plasma-assisted ALD exhibits negligible trap-assisted (Poole–Frenkel) conduction unlike the thermal ALD films, resulting in higher breakdown electric fields than the thermal ALD prepared films.