# US 9,520,488 B2 · Silicon-controlled rectifier electrostatic discharge protection device and method for forming the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,488 B2 - Document ID: US9520488B2 - Status: Granted - Kind: B2 - Application number: 14/332,534 - Filed: 2014-07-16 - Published: 2015-07-02 - Granted: 2016-12-13 - Earliest claimed: 2013-12-30 - Assignees: Semiconductor Manufacturing International (Shanghai) Corporation - Applicants: Semiconductor Manufacturing International (Shanghai) Corporation - Inventors: Meng Dai - Web page: https://patentgrep.com/patent/US9520488B2 ## CPC - H10D 18/251: {Lateral thyristors} - H10D 8/041: {of multilayer diodes} - H10D 8/80: PNPN diodes, e.g. Shockley diodes or break-over diodes - H10D 89/713: {including a PNP transistor and a NPN transistor, wherein each of said transistors has its base region coupled to the collector region of the other transistor, e.g. silicon controlled rectifier [SCR] devices} - H10D 62/108: {having localised breakdown regions, e.g. built-in avalanching regions (in self-protected thyristors H10D18/211)} - H10D 62/115: {Dielectric isolations, e.g. air gaps} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract Various embodiments provide SCR ESD protection devices and methods for forming the same. An exemplary device includes a semiconductor substrate having a P-type well region, an N-type well region adjacent to the P-type well region, a first P-type doped region and a first N-type doped region in the P-type well region, and a second N-type doped region and a second P-type doped region in the N-type well region. A first center-doped region and a second center-doped region doped with impurity ions of a same type are located between the first N-type doped region and the second P-type doped region and extend across the P-type well region and the N-type well region. The first center-doped region is located within the second center-doped region, has a doping concentration higher than a doping concentration in the second center-doped region, and has a depth smaller than a depth of the second center-doped region. ## Claims ### Claim 1 A silicon-controlled rectifier (SCR) electrostatic discharge protection (ESD) device, comprising: a semiconductor substrate having a P-type well region and an N-type well region adjacent to the P-type well region; a first P-type doped region in the P-type well region; a first N-type doped region in the P-type well region between the first P-type doped region and the N-type well region; a second N-type doped region in the N-type well region; a second P-type doped region in the N-type well region between the second N-type doped region and the P-type well region; and a first center-doped region and a second center-doped region, wherein the first center-doped region and the second center-doped region are located between the first N-type doped region and the second P-type doped region and extend across the P-type well region and the N-type well region, the first center-doped region is located within and enclosed by the second center-doped region, the second center-doped region has a depth greater than a depth of the first center-doped region, and the first center-doped region and the second center-doped region are doped with impurity ions of a same type, a concentration of the impurity ions in the first center-doped region being higher than a concentration of the impurity ions in the second center-doped region. ### Claim 2 (depends on 1) The device according to claim 1, wherein: the impurity ions doped in the first center-doped region and the second center-doped region are N-type, the depth of the second center-doped region is smaller than a depth of the N-type well region, and the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the N-type well region. ### Claim 3 (depends on 2) The device according to claim 2, wherein the concentration of the impurity ions in the N-type well region is less than about 1E18 atom/cm3, the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm3 to about 1E19 atom/cm3, and the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm3. ### Claim 4 (depends on 1) The device according to claim 1, wherein: the impurity ions doped in the first center-doped region and the second center-doped region are P-type, the depth of the second center-doped region is smaller than a depth of the P-type well region, and the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the P-type well region. ### Claim 5 (depends on 4) The device according to claim 4, wherein the concentration of the impurity ions in the P-type well region is less than about 1E18 atom/cm3, the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm3 to about 1E19 atom/cm3, and the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm3. ### Claim 6 (depends on 1) The device according to claim 1, further comprising a shallow trench isolation (STI) structure between adjacent doped regions. ### Claim 7 (depends on 1) The device according to claim 1, wherein the concentration of the impurity ions in the second center-doped region is gradually increased from a lower surface of the second center-doped region to an upper surface of the second center-doped region. ### Claim 8 (depends on 1) The device according to claim 1, wherein: the first N-type doped region contains a plurality of discrete third P-type doped regions to divide the first N-type doped region into a plurality of first N-type sub-doped regions, and one discrete third P-type doped region is between and in contact with adjacent first N-type sub-doped regions. ### Claim 9 (depends on 1) The device according to claim 1, wherein: the second P-type doped region contains a plurality of discrete third N-type doped regions to divide the second P-type doped region into a plurality of second P-type sub-doped regions, and one discrete third N-type doped region is between and in contact with adjacent second P-type sub-doped regions. ### Claim 10 (depends on 1) The device according to claim 1, wherein the first center-doped region and the second center-doped region are co-centered. ### Claim 11 (depends on 1) The device according to claim 1, wherein the first N-type doped region, the P-type well region, and the second center-doped region form a parasitic NPN transistor. ### Claim 12 A method for forming an SCR ESD device, comprising: providing a semiconductor substrate; forming, in the semiconductor substrate, a P-type well region and an N-type well region adjacent to the P-type well region; forming a second center-doped region that extends across the P-type well region and the N-type well region; forming a first center-doped region in and enclosed by the second center-doped region, a depth of the second center-doped region being greater than a depth of the first center-doped region, wherein the first center-doped region and the second center-doped region are doped with impurity ions of a same type, a concentration of the impurity ions in the first center-doped region being higher than a concentration of the impurity ions in the second center-doped region; forming a first P-type doped region in the P-type well region at a first side of the second center-doped region; forming a first N-type doped region in the P-type well region at the first side of the second center-doped region, the first N-type doped region being located between the first P-type doped region and the second center-doped region; forming a second N-type doped region in the N-type well region at a second side of the second center-doped region; and forming a second P-type doped region in the N-type well region at the second side of the second center-doped region, the second P-type doped region being located between the second N-type doped region and the second center-doped region. ### Claim 13 (depends on 12) The method according to claim 12, wherein: the impurity ions doped in the first center-doped region and the second center-doped region are N-type, the depth of the second center-doped region is smaller than a depth of the N-type well region, and the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the N-type well region. ### Claim 14 (depends on 13) The method according to claim 13, wherein the concentration of the impurity ions in the N-type well region is less than about 1E18 atom/cm3, the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm3 to about 1E19 atom/cm3, and the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm3. ### Claim 15 (depends on 12) The method according to claim 12, wherein: the impurity ions doped in the first center-doped region and the second center-doped region are P-type, the depth of the second center-doped region is smaller than a depth of the P-type well region, and the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the P-type well region. ### Claim 16 (depends on 15) The method according to claim 15, wherein the concentration of the impurity ions in the P-type well region is less than about 1E18 atom/cm3, the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm3 to about 1E19 atom/cm3, and the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm3. ### Claim 17 (depends on 12) The method according to claim 12, further comprising: forming an STI structure between adjacent doped regions. ### Claim 18 (depends on 12) The method according to claim 12, wherein: when the impurity ions doped in the first center-doped region are N-type, the first center-doped region, the first N-type doped region, and the second N-type doped region are formed by a same N-type ion implantation process; and when the impurity ions doped in the first center-doped region are P-type, the first center-doped region, the first P-type doped region, and the second P-type doped region are formed by a same P-type ion implantation process. ### Claim 19 (depends on 12) The method according to claim 12, wherein the first center-doped region and the second center-doped region are co-centered. ### Claim 20 (depends on 12) The method according to claim 12, wherein the first N-type doped region, the P-type well region, and the second center-doped region form a parasitic NPN transistor.