Low-frequency noise and stress-induced degradation in LDMOS

Low frequency noise (LFN) characteristics of high voltage double reduced-surface-field LDMOS with SiO₂ as gate dielectric is investigated and the effect of DC stressing has been observed. It has been found that the LDMOS does not follow typical noise behavior of ordinary MOSFETs as extended drain attributes a significant role at higher gate overdrive voltages. Here, separation of the overall measured noise components to three distinct regions is proposed: the channel, the resistive region under the gate oxide and that under the field oxide layer. Induced and inherent noise components coming from the extended drain region under the gate and field oxides are separated from the channel noise by performing noise measurements in DNWell standalone resistors.