Investigation of NBTI Recovery During Measurement

In this work we present a rigorous investigation of the negative bias temperature instability (NBTI) recovery process during measurement intervals in comparison to the numerical solution of an extended reaction-diffusion (RD) model. In contrast to previous work, the RD model has been implemented in a multi-dimensional device simulator and is solved selfconsistently together with the semiconductor device equations. This allows us to directly use many commonly approximated quantities such as the oxide electric field and the interface hole concentration in a self-consistent manner. In addition, the influence of the trapped charges can be more accurately considered by using a distributed Shockley-Read-Hall interface trap-charge model [1, 2] which has been coupled to the RD model. Thus, due to the self-consistent solution procedure, also the feedback of these charged interface-states on the Poisson equation is considered which influences the observed threshold voltage shift. Experimental data confirm the model which has been calibrated to a wide range of temperatures using a single set of parameters.