Bias Polarity Dependence Of Charge Trapping Behaviours In La-Incorporated Hafnium-Based Dielectric

Bias temperature instability of metal-oxide-semiconductor field effect transistors (MOSFETs) with various concentrations of La incorporation in Hf-based dielectrics was characterized by varying the magnitude and polarity of the stress biases. Contrasting dependences of charge trapping on the magnitude of the stress biases are shown by changing the bias polarity. A model based on the distortion of asymmetric energy band diagrams and La-induced interface dipoles is suggested to explain this behaviour. Change of gate leakage currents according to La-incorporation, magnitude, and polarity of bias stresses supports the validity of the model. (C) 2011 American Institute of Physics. [doi:10.1063/1.3624922]