Bias Temperature Instability Characteristics of n- and p-Type Field Effect Transistors Using HfO2Gate Dielectrics and Metal Gate

This study examined the positive bias temperature instability (PBTI) of n-type metal-oxide-semiconductor field effect transistor (nMOSFET) characteristics and the negative bias temperature instability (NBTI) of p-type metal-oxide-semiconductor field effect transistor (pMOSFET) characteristics of HfO2gate dielectrics with a metal gate. The interface trap charge (ΔNit)and bulk oxide trap charge (ΔNot)densities were separately estimated to determine the defects responsible for the threshold voltage (Vth)shift during the BTI stress. The contribution of ΔNitto the Vthshift for nMOSFET PBTI and pMOSFET NBTI was ∼5and ∼30%, respectively. In addition, the estimated activation energy (Ea)of ΔNitand ΔNotwas 0.10 and 0.03 eV, respectively, for nMOSFET PBTI, and 0.11 and 0.17 eV, respectively, for pMOSFET NBTI. It was confirmed that the main degradation mechanism of nMOSFET PBTI is related to the generation of oxide trap charges. However, the degradation under pMOSFET NBTI stress is due to the generation of both interface states and oxide trap charges. By measuring the stress and recovery characteristics under various bias conditions, it was also found that the electron trapping/detrapping characteristics are dominant in the nMOSFET, whereas the generation of both hole trapping/detrapping and interface states competitively occurs in the pMOSFET.