Effect of Source & Drain Side Abutting on the Low Current Filamentation in LDMOS-SCR Devices

The concept of abutting source/body and drain/anode junctions is studied in detail in a high voltage LDMOS-SCR with 2D and 3D TCAD simulations. The SCR turn-on and low current filament formation are strongly influenced by the isolation at the anode and cathode side in the LDMOS-SCR. While the anode side isolation impacts the filament-induced failures at low currents, the cathode side isolation has a minor impact. Physical insights are given on the SCR turn-on degradation with abutting and its influence on the filament formation and spreading. The obtained understanding helps to build an ESD robust, self-protected LDMOS-SCRs.