Influence of Hole Current Crowding on Snapback Breakdown in Multi-Finger MOSFETs

Abstract

The snapback breakdown behavior of multi-finger MOSFETs was investigated using a device simulation. It is shown that snapback breakdown voltage (SNBV) varies depending on the source/drain configuration, even with the same two-finger structure. This results from the hole current crowding below the shared source, which further increases forward biasing at the source-substrate junction and eventually leads to premature activation of the parasitic bipolar junction transistor (BJT). Double-pocket implantation successfully suppresses the hole current crowding and also achieves higher SNBV for two-finger MOSFET.

Keywords

• Snapback breakdown
• impact ionization
• parasitic bipolar junction transistor (BJT)
• pocket implantation
• multi-finger MOSFET