Modeling of hot-carrier degradation in LDMOS devices using a drift-diffusion based approach

We model hot-carrier degradation (HCD) in n- and p-channel LDMOS transistors using an analytic approximation of the carrier energy distribution function (DF). Carrier transport, which is an essential ingredient of our HCD model, is described using the drift-diffusion (DD) method. The analytical DF is used to evaluate the bond-breakage rates. As a reference, we also obtain the DF from the solution of the Boltzmann transport equation using the spherical harmonics expansion (SHE) method. The distribution functions and interface state density profiles computed using the SHE and DD-based approaches are compared. The comparison of the device degradation characteristics simulated by these two approaches with the experimental data shows that the DD-based variant, which is considerably less computationally expensive, provides good accuracy. We, therefore, conclude that the DD-based version is efficient for predictive HCD simulations in LDMOS devices.