Patent ID: 7202114

Claim:
A method of forming a high holding low voltage trigger silicon controlled rectifier (HHLVTSCR) comprising the steps of: providing a crystalline silicon substrate with p-type doping concentration in the range of 5×10 15 cm −3 and an epitaxially-grown n-type layer; depositing a deep N-tub layer in an effective area of the HHLVTSCR; ion implanting or diffusing N and P type impurities forming an N-well with average doping concentration in the range of 8×10 17 cm −3 and a P-well with average doping in the range of 2.6×10 18 cm −3 spaced at an optimized distance over the N-tub layer, forming N- and P-type high-doping concentration regions laterally spaced from each other at optimized distances in each of the N-well and P-well; forming an N type high-doping concentration bridge region over the N-well to P-well junction for an N- HHLVTSCR and a P type high-doping concentration bridge region over the N-well to P-well junction for a P - HHLVTSCR of an optimized dimension and distance from the other regions; forming an insulated gate over the N-well for the P- HHLVTSCR and an insulated gate over the P-well for the N- HHLVTSCR; forming a common contact for the high-doping concentration n- and p-type regions in the P-well and the gate for the N- HHLVTSCR and a common contact for the high-doping concentration n- and p-type regions in the P-well for the P- HHLVTSCR; selectively forming either a common contact for the high-doping concentration n-and p-type regions in the N-well and the gate or a common contact for the high-doping concentration p-type region in the N-well and the gate and a separate contact for the high-doping concentration p-type region in the N-well for the P- HHLVTSCR; and selectively forming either a common contact or separate contacts for the high-doping concentration n- and p-type regions in the N-well for the N-HHLVTSCR.