Simulation of nonequilibrium thermal effects in power LDMOS transistors

The present work considers electrothermal simulation of LDMOS devices and associated nonequilibrium effects. Simulations have been performed on three kinds of LDMOS: bulk Si, partial SOI and full SOI. Differences between equilibrium and nonequilibrium modeling approaches are examined. The extent and significance of thermal nonequilibrium is determined from phonon temperature distributions obtained using a common electronic solution and three different heating models (Joule heating, electron/lattice scattering, phonon scattering). The results indicate that, under similar operating conditions, nonequilibrium behavior is more significant in the case of full SOI devices, where the extent of nonequilibrium is estimated to be twice that of the partial SOI device and four times that of the bulk device. Time development of acoustic phonon and lattice temperatures in the electrically active region indicates that nonequilibrium effects are significant for times less than 10 ns. 2003 Elsevier Science Ltd. All rights reserved.