Physical and Electrical Properties of HfAlOxFilms Prepared by Atomic Layer Deposition Using NH3/Ar Plasma

The effects of introducing NH3/Ar plasma pulses during the atomic layer deposition (ALD) of HfAlOx films and during the in situ nitridation of an interfacial layer (IL) on the properties of HfAlOx-FETs were investigated. The interaction between HfAlOx and IL and the dopant penetration were suppressed by the introduction of a NH3/Ar plasma pulse during ALD, because it increases the nitrogen content at the interface of HfAlOx/IL. Moreover, the nitrogen content in the IL could be controlled by adjusting the number of NH3/Ar plasma pulses used for in situ nitridation. No threshold voltage shift due to the nitridation of the Si substrate was observed, indicating that the nitrogen profile was well controlled when using a NH3/Ar plasma pulse for in-situ nitridation. It was found that in-situ nitridation with 5 cycles of NH3/Ar plasma pulses was optimum for reducing C–V hysteresis and improving carrier mobility.