An advanced no-snapback LDMOSFET with optimized breakdown characteristics of drain n-n+ diodes

Snapbacks in sustain characteristics of lateral double-diffused MOSFETs (LDMOSFETs) are caused by positive feedbacks between the turn-on of the bipolar junction transistors (BJTs) and the avalanche breakdown of the drain n-n⁺ diodes . Although the n-n⁺ diodes are thus one of the most basic parasitic devices, which play a leading role in the snapback characteristics, neither a textbook nor a paper has ever described their breakdown characteristics in depth so as to realize a simple no-snapback LDMOSFET. This paper analyzes the snapback characteristics of n-n⁺ diodes and their mechanisms in detail. The no-snapback theory derived from this study is applied to an advanced no-snapback LDMOSFET with a simple structure, as an improved version of the conventional no-snapback LDMOSFET , which endures the electrostatic discharge (ESD) criterion for automotive applications: 15 kV, 150 pF, and 150 Ω.