Patent ID: 8329542
Filing Date: 2012-12-11
Classification: H01L

Abstract:
1. A method for forming a hybrid-mode LDMOS device having both mosfet and bipolar modes of operation comprising: providing a substrate of first conductivity; in the substrate forming a well of second conductivity; at the bottom of the well of second conductivity forming a buried layer of second conductivity; forming a well of first conductivity in the well of second conductivity; forming first and second drain collector diffusions extending from the surface of the substrate to the buried layer; forming a field oxide region between the two drain collector diffusions and adjacent the second drain collector diffusion; forming a source emitter diffusion extending from the surface of the substrate into the well of first conductivity, proximate the field oxide region and between the field oxide region and the first drain collector region; above the well of first conductivity forming a main gate on the surface of the substrate, the main gate spaced from the first drain collector diffusion thereby establishing a drift region between the first drain collector diffusion and the main gate; and forming a control gate between the first gate and the source emitter diffusion; whereby turning on both gates on places the hybrid-mode LDMOS device in the mosfet mode and turning on the main gate on and turning off the control gate places the hybrid-mode LDMOS in the bipolar mode.