Anomalous Safe Operating Area and Hot Carrier Degradation of NLDMOS Devices

Automotive and telecom applications often require voltages in the 20-30 V range. These circuits combine high-performance CMOS with a high-voltage MOS transistor. A possible choice for the high-voltage device is an n-channel lateral DMOS (NLDMOS) transistor. An advantage of an NLDMOS transistor is that it can be easily integrated within existing technologies without significant process changes. In most cases, though, the drain drift implant must be optimized to meet safe operating area (SOA) and hot carrier (HC) reliability requirements. This paper focuses on understanding anomalous SOA and HC results obtained from an NLDMOS transistor whose drain drift implant dose was varied