Patent ID: 7855399
Filing Date: 2010-12-21
Classification: H01L

Abstract:
1. A protection device of programmable semiconductor surge suppressor having deep-well structure comprising: one, two or four protection units, each of the protection units being composed of a PN-junction diode, a PNPN-type thyristor and a NPN-type triode; anode of the diode and cathode of the thyristor, connected with each other, act together as Port K of the protection unit; cathode of the diode, anode of the thyristor and collector of the triode, connected with each other, act together as Port A of the protection unit; and emitter of the triode and gate of the thyristor are connected with each other, base of the triode acting as Port G of the protection unit; wherein said protection device used an N-type semiconductor base as a substrate, viewed from the top, each of the protection units corresponds to a semiconductor active region which is composed of a diode area, a thyristor area and a triode area; viewed from the cross section, in the diode area on the frontal side of the substrate are positioned sequentially from top to bottom a P-type heavy diffusion layer and a P-type diffusion layer, in the diode area on the reverse side of the substrate is positioned from bottom to top an N-type heavy implanted layer, between the P-type diffusion layer and the N-type heavy implanted layer of the diode area is an N-type light doped layer of the substrate itself, and thus in the diode area is formed a PN junction with impurity concentration changed gradiently from top to bottom according to the order of P+, P, N and N+; and a group of deep-well are positioned at intervals at the interface between the P-type diffusion layer and the N-type light doped layer, each of the deep-well being formed by means of boring a contact or trenching a trench downwards from the top of the N-type light doped layer before depositing P-type doped or P-type light doped materials in the contact or trench, the top of the P-type doped or P-type light doped materials deposited in the contact or trench being connected with the bottom of the P-type diffusion layer, thus a concave-convex interface being formed in the PN junction.