# US 12,009,357 B2 · Diode-triggered bidirectional silicon controlled rectifier and circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,357 B2 - Document ID: US12009357B2 - Status: Granted - Kind: B2 - Application number: 17/451,173 - Filed: 2021-10-18 - Published: 2023-01-26 - Granted: 2024-06-11 - Earliest claimed: 2021-07-22 - Assignees: Changxin Memory Technologies, Inc. - Applicants: Changxin Memory Technologies, Inc. - Inventors: Pan Mao; Yingtao Zhang; Junjie Liu; Lingxin Zhu; Bin Song; Qian Xu; Tieh-Chiang Wu - Web page: https://patentgrep.com/patent/US12009357B2 ## CPC - H10D 62/115: {Dielectric isolations, e.g. air gaps} - H10D 89/60: Integrated devices comprising arrangements for electrical or thermal protection, e.g. protection circuits against electrostatic discharge [ESD] - H10D 8/00: Diodes (variable-capacitance diodes H10D1/64; gated diodes H10D12/00) - H10D 8/80: PNPN diodes, e.g. Shockley diodes or break-over diodes - H10D 18/80: Bidirectional devices, e.g. triacs - H10D 89/00: Aspects of integrated devices not covered by groups H10D84/00 - H10D88/00 - 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 89/611: {using diodes as protective elements} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract The present disclosure provides a diode-triggered bidirectional silicon controlled rectifier and circuit. The silicon controlled rectifier includes: a P-type substrate; a first P well formed in the P-type substrate, a first P-type doped region and a first N-type doped region being formed in the first P well; a second P well formed in the P-type substrate, a third N-type doped region and a fourth P-type doped region being formed in the second P well; and an N well formed in the P-type substrate, a second P-type doped region, a second N-type doped region and a third P-type doped region being formed in the N well. The second N-type doped region is electrically connected with a positive electrode of a diode string, and the first P-type doped region and the fourth P-type doped region are electrically connected with a negative electrode of the diode string. ## Claims ### Claim 1 A diode-triggered bidirectional silicon controlled rectifier, comprising a silicon controlled rectifier (SCR) and a diode string, the silicon controlled rectifier having an anode and a cathode and comprising: a P-type substrate; a first P well formed in the P-type substrate, a first P-type doped region and a first N-type doped region being formed in the first P well; a second P well formed in the P-type substrate, a third N-type doped region and a fourth P-type doped region being formed in the second P well; and an N well formed in the P-type substrate, a second P-type doped region, a second N-type doped region and a third P-type doped region being formed in the N well; wherein the first N-type doped region and the third P-type doped region are electrically connected with the anode; the third N-type doped region and the second P-type doped region are electrically connected with the cathode; the second N-type doped region is electrically connected with a positive electrode of the diode string, and the first P-type doped region and the fourth P-type doped region are electrically connected with a negative electrode of the diode string. ### Claim 2 (depends on 1) The diode-triggered bidirectional silicon controlled rectifier according to claim 1, wherein the first P-type doped region, the second P-type doped region, the third P-type doped region, the fourth P-type doped region, the first N-type doped region, the second N-type doped region and the third N-type doped region are all heavily doped regions, and the first P well, the second P well and the N well are all lightly doped regions. ### Claim 3 (depends on 1) The diode-triggered bidirectional silicon controlled rectifier according to claim 1, wherein the first P well and the second P well are closely adjacent to the N well, and the first P well and the second P well are distributed symmetrically with respect to a central axis of the N well; wherein the first P-type doped region and the fourth P-type doped region are symmetrical with respect to the central axis of the N well, the first N-type doped region and the third N-type doped region are symmetrical with respect to the central axis of the N well, and the second P-type doped region and the third P-type doped region are symmetrical with respect to the central axis of the N well. ### Claim 4 (depends on 3) The diode-triggered bidirectional silicon controlled rectifier according to claim 3, wherein as seen in a direction from the first P well towards the second P well via the N well, the doped regions are the first P-type doped region, the first N-type doped region, the second P-type doped region, the second N-type doped region, the third P-type doped region, the third N-type doped region, and the fourth P-type doped region in sequence. ### Claim 5 (depends on 1) The diode-triggered bidirectional silicon controlled rectifier according to claim 1, wherein a deep N well is formed in the P-type substrate, and the first P well, the N well and the second P well are disposed on an upper surface of the deep N well. ### Claim 6 (depends on 1) The diode-triggered bidirectional silicon controlled rectifier according to claim 1, wherein shallow trench isolation structures are formed between adjacent doped regions, with depths of the doped regions being less than depths of the shallow trench isolation structures. ### Claim 7 (depends on 1) The diode-triggered bidirectional silicon controlled rectifier according to claim 1, wherein a number of diodes in the diode string is greater than or equal to 0. ### Claim 8 (depends on 7) The diode-triggered bidirectional silicon controlled rectifier according to claim 7, wherein the diode string comprises a fifth diode and a sixth diode; a positive electrode of the fifth diode is the positive electrode of the diode string, a negative electrode of the fifth diode is connected with a positive electrode of the sixth diode, and a negative electrode of the sixth diode is the negative electrode of the diode string. ### Claim 9 A diode-triggered circuit, comprising: a forward diode trigger circuit, the forward diode trigger circuit comprising a first diode, a diode string and a second diode; a reverse diode trigger circuit, the reverse diode trigger circuit comprising a third diode, a diode string and a fourth diode; a forward silicon controlled rectifier (SCR) loop, the forward SCR loop comprising a first PNP bipolar transistor and a first NPN bipolar transistor; and a reverse SCR loop, the reverse SCR loop comprising a second PNP bipolar transistor and a second NPN bipolar transistor; wherein the forward diode trigger circuit and the reverse diode trigger circuit share the diode string. ### Claim 10 (depends on 9) The diode-triggered circuit according to claim 9, wherein a positive electrode of the first diode is connected with an anode, a negative electrode of the first diode is connected with a positive electrode of the diode string, a negative electrode of the diode string is connected with a positive electrode of the second diode, and a negative electrode of the second diode is connected with a cathode; the forward diode trigger circuit is from the anode to the cathode via the first diode, the diode string and the second diode. ### Claim 11 (depends on 10) The diode-triggered circuit according to claim 10, wherein a number of diodes in the diode string is greater than or equal to 0. ### Claim 12 The diode-triggered circuit according to 11, wherein the diode string comprises a fifth diode and a sixth diode; a positive electrode of the fifth diode is the positive electrode of the diode string, a negative electrode of the fifth diode is connected with a positive electrode of the sixth diode, and a negative electrode of the sixth diode is the negative electrode of the diode string. ### Claim 13 (depends on 9) The diode-triggered circuit according to claim 9, wherein a positive electrode of the third diode is connected with a cathode, a negative electrode of the third diode is connected with a positive electrode of the diode string, a negative electrode of the diode string is connected with a positive electrode of the fourth diode, and a negative electrode of the fourth diode is connected with an anode; the reverse diode trigger circuit is from the cathode to the anode via the third diode, the diode string and the fourth diode. ### Claim 14 (depends on 13) The diode-triggered circuit according to claim 13, wherein a number of diodes in the diode string is greater than or equal to 0. ### Claim 15 (depends on 9) The diode-triggered circuit according to claim 9, wherein a base of the first PNP bipolar transistor is a collector of the first NPN bipolar transistor, a base of the first NPN bipolar transistor is a collector of the first PNP bipolar transistor, the base of the first PNP bipolar transistor is connected with a positive electrode of the diode string, the collector of the first PNP bipolar transistor is connected with a negative electrode of the diode string, an emitter of the first PNP bipolar transistor is connected with an anode, and an emitter of the first NPN bipolar transistor is connected with a cathode; the forward SCR loop is from the anode to the cathode via the first PNP bipolar transistor and the first NPN bipolar transistor. ### Claim 16 (depends on 15) The diode-triggered circuit according to claim 15, wherein a number of diodes in the diode string is greater than or equal to 0. ### Claim 17 (depends on 9) The diode-triggered circuit according to claim 9, wherein a base of the second PNP bipolar transistor is a collector of the second NPN bipolar transistor, a base of the second NPN bipolar transistor is a collector of the second PNP bipolar transistor, the base of the second PNP bipolar transistor is connected with a positive electrode of the diode string, the collector of the second PNP bipolar transistor is connected with a negative electrode of the diode string, an emitter of the second NPN bipolar transistor is connected with an anode, and an emitter of the second PNP bipolar transistor is connected with a cathode; the reverse SCR loop is from the cathode to the anode via the second PNP bipolar transistor and the second NPN bipolar transistor. ### Claim 18 (depends on 17) The diode-triggered circuit according to claim 17, wherein a number of diodes in the diode string is greater than or equal to 0. ### Claim 19 (depends on 9) The diode-triggered circuit according to claim 9, wherein a number of diodes in the diode string is greater than or equal to 0. ### Claim 20 The diode-triggered circuit according to 19, wherein the diode string comprises a fifth diode and a sixth diode; a positive electrode of the fifth diode is the positive electrode of the diode string, a negative electrode of the fifth diode is connected with a positive electrode of the sixth diode, and a negative electrode of the sixth diode is the negative electrode of the diode string.