Patent ID: 7542253

Claim:
An SCR (Silicon Controlled Rectifier) for ESD (Electrostatic Discharge) protection comprising: two terminal electrodes of a first electrode and a second electrode; a PMOS device configured to provide ESD protection between a PAD line and a VDD line; an NMOS device configured to provide ESD protection between the PAD line and a VSS line; and an SCR structure comprising a power-rail ESD clamp device connected between the VDD line and the VSS line, the SCR further comprising a first P-typed high-doped region (P+) electrically connected to a second P-typed high-doped region (P+), and a first N-typed high-doped region (N+) electrically connected to a second N-typed high-doped region (N+), wherein the second P-typed high-doped region (P+) is an anode and the second N-typed high-doped region (N+) is a cathode, wherein said PMOS device is connected to said first electrode and said NMOS device is connected to second electrode, while said SCR structure is placed between said PMOS device and said NMOS device, said SCR structure being embedded in said PMOS device and said NMOS device, to form a circuit protection, wherein the combination of the PMOS device, the NMOS device, and the SCR structure forms a single I/O cell.