Electric Field Engineering to Extend Capability of NLDMOS from 70V to 90V Without Added Cost

In a given multipurpose BCD technology, the device implants are set by the main workhorse devices. Typically, doping levels are determined by optimizing Rsp and other key properties of the main devices, often settling with optimized Rsp-Bvdss trade-off. In some cases, HV applications (in particular automotive) require devices with higher Bvdss (breakdown) e.g. for level shifting to floating domains, switching external HV signals, protecting the IC against overstress, etc. This requires boosting the Bvdss of a given technology without adding cost or additional process steps. Moreover, the device architecture needs to be portable across many flavors of the core process, including e.g. SOI (Silicon On Insulator) version. This work outlines an architecture that increases operating voltage of NLDMOS device from 70V to 90V by electric field engineering. The proposed solution doesn’t require new layers and is portable to other technologies.