A Novel 'I-V Spectroscopy' Technique To Deconvolve Threshold Voltage And Mobility Degradation In Ldmos Transistors

Although the CMOS-compatible Laterally Diffused MOSFET (LDMOS) is widely used in various applications as a versatile and efficient power electronic device, its hot carrier degradation (HCD) remains a persistent and important design challenge. None of the classical HCD models apply, because the geometric and doping complexities of the channel and drift regions create multiple hotspots with bias-dependent hot carrier injection into the oxide. To address these challenges, here we: 1) propose a novel geometrical partition of the LDMOS and represent each part by a TCAD-calibrated and experimentally validated tandem-FET compact model; 2) use the new compact model to propose an 'I -V spectroscopy' methodology to deconvolve mobility and threshold degradation in the channel and the drift regions; 3) separate the degradation in the two regions by post-processing measured I-V curves; 4) demonstrate that Delta V-th determined by classical techniques, e.g., constant current (CC) or maximum transconductance (Gmmax), are contaminated by mobility degradation and must be corrected by the proposed technique for accurate lifetime projection.