Esd protection device with bidirectional diode string-triggering scr structure

An ESD protection device for bidirectional diode string triggering SCR structure, comprising a diode string formed by a well splitting technique, a bidirectional SCR structure and a metal wire, wherein

• the bidirectional SCR structure and the diode string comprise a P substrate, a deep N well, a first P well, a first N well, a second P well, a second N well, a first P+ implantation region, a first N+ implantation region, a second P+ implantation region, a second N+ implantation region, a third P+ implantation region, a third N+ implantation region, a fourth P+ implantation region and a fourth N+ implantation region, wherein the deep N well is arranged on the P substrate, and the first P well, the first N well, the second P well and the second N well are successively arranged from left to right on a surface region of the deep N well;
• the left edge of the first P well is connected with the left edge of the deep N well;
• the right side of the first P well is connected with the left side of the first N well;
• the right side of the first N well is connected with the left side of the second P well;
• the right edge of the second P well is connected with the left side of the second N well;
• the right edge of the second N well is connected with the right edge of the deep N well;
• the first P+ implantation region and the first N+ implantation region are successively arranged from left to right on the surface region of the first P well;
• the second P+ implantation region and the second N+ implantation region are successively arranged from left to right on the surface region of the first N well;
• the third P+ implantation region and the third N+ implantation region are successively arranged from left to right on the surface region of the second P well;
• the fourth P+ implantation region and the fourth N+ implantation region are successively arranged from left to right on the surface region of the second N well;
• in the second N well region, a mask preparing plate is used to insert a plurality of P wells at intervals;
• the circumference of each P well is isolated by the N well;
• different quantities of diodes are prepared to form a diode string which assists a departure path to effectively suppress the Darlington effect;
• the surface region of each P well is respectively provided with a pair of P+ implantation region and N+ implantation region;
• trigger voltage is controlled by increasing or decreasing the number of diodes formed by well splitting;
• the metal wire is used to connect the implantation region, and lead out two electrodes from the metal wire respectively as the forward conduction and reverse conduction of the ESD protection device, to ensure that a diode formed by well splitting assists a trigger path in conducting, thereby reducing the trigger voltage and turn-on time of the ESD protection device.