# US 8,786,362 B1 · Schottky diode having current leakage protection structure and current leakage protecting method of the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,362 B1 - Document ID: US8786362B1 - Status: Granted - Kind: B1 - Application number: 13/909,097 - Filed: 2013-06-04 - Granted: 2014-07-22 - Earliest claimed: 2013-06-04 - Assignees: United Microelectronics Corp. - Applicants: United Microelectronics Corporation - Inventors: An-Hung Lin; Wei-Shan Liao; Bo-Jui Huang; Hong-Ze Lin; Ting-Zhou Yan; Wen-Chun Chang - Web page: https://patentgrep.com/patent/US8786362B1 ## CPC - H10D 8/60: Schottky-barrier diodes - H10W 10/031: {of isolation regions comprising PN junctions} - H10W 10/30: Isolation regions comprising PN junctions - H10D 62/106: {having supplementary regions doped oppositely to or in rectifying contact with regions of the semiconductor bodies, e.g. guard rings with PN or Schottky junctions} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A Schottky diode having a current leakage protection structure includes a Schottky diode unit, a first isolation portion and a second isolation portion. The Schottky diode unit is defined in a substrate and includes a metalized anode, an active region having dopants of first conductive type, a cathode and at least one isolation structure. The first isolation portion having dopants of second conductive type is formed between substrate and active region, and the first isolation portion includes a first well disposed beneath active region, and a first guard ring surrounding active region and connecting to the first well. The second isolation portion having dopants of first conductive type is formed between substrate and the first isolation portion, and the second isolation portion includes a second well disposed beneath the first well, and a second guard ring surrounding the first guard ring and connecting to the second well. ## Claims ### Claim 1 A Schottky diode having a current leakage protection structure, comprising: a Schottky diode unit, defined in a substrate and comprising: an active region, having dopants of a first conductive type; a metalized anode, formed on the active region; a cathode, formed atop the active region; and at least one isolation structure, formed between the metalized anode and the cathode; a first isolation portion, having dopants of a second conductive type, formed between the substrate and the active region, and comprising: a first well, disposed beneath the active region; and a first guard ring, surrounding the active region and connecting to the first well; and a second isolation portion, having dopants of the first conductive type, formed between the substrate and the first isolation portion, and comprising: a second well, disposed beneath the first well; and a second guard ring, surrounding the first guard ring and connecting to the second well. ### Claim 2 (depends on 1) The Schottky diode according to claim 1, wherein the first conductive type is N-type, and the second conductive type is P-type. ### Claim 3 (depends on 1) The Schottky diode according to claim 1, wherein a concentration of dopants of the second conductive type in the first isolation portion is greater than a concentration of dopants of the first conductive type in the active region. ### Claim 4 (depends on 1) The Schottky diode according to claim 1, wherein the metalized anode is formed of a salicide. ### Claim 5 (depends on 1) The Schottky diode according to claim 1, wherein a concentration of dopants of the first conductive type in the cathode is greater than a concentration of dopants of the first conductive type in the active region. ### Claim 6 (depends on 5) The Schottky diode according to claim 5, wherein the cathode is isolated from the first isolation portion with an additional isolation structure. ### Claim 7 (depends on 1) The Schottky diode according to claim 1, further comprising a body region, an anode contact region and a metal barrier layer, wherein the body region is formed beneath the metalized anode, the anode contact region is formed between the metalized anode and the body region, and the metal barrier layer is formed on the isolation structure and surrounds the metalized anode. ### Claim 8 (depends on 7) The Schottky diode according to claim 7, wherein the body region and the anode contact region both have dopants of the second conductive type, and a concentration of dopants of the second conductive type in the anode contact region is greater than a concentration of dopants of the second conductive type in the body region. ### Claim 9 (depends on 1) The Schottky diode according to claim 1, further comprising a first contact region formed atop the first guard ring and a second contact region formed atop the second guard ring, wherein the first contact region and the second contact region are isolated from each other with an additional isolation structure. ### Claim 10 (depends on 9) A current leakage protecting method of the Schottky diode according to claim 9, comprising: coupling the metalized anode to a first voltage, and coupling the cathode to a second voltage, wherein the first voltage is set to be equal to or higher than the second voltage; and coupling the first contact region to a third voltage, and coupling the second contact region to a fourth voltage, wherein the fourth voltage is set to be higher than the third voltage. ### Claim 11 (depends on 10) The current leakage protecting method according to claim 10, further comprising setting the third voltage as an independent ground. ### Claim 12 (depends on 9) The Schottky diode according to claim 9, wherein a concentration of dopants of the second conductive type in the first contact region is greater than a concentration of dopants of the second conductive type in the first guard ring, and a concentration of dopants of the first conductive type in the second contact region is greater than a concentration of dopants of the first conductive type in the second guard ring. ### Claim 13 (depends on 12) The current leakage protecting method according to claim 12, wherein a forward bias is formed between the metalized anode and the cathode as the first voltage is set to be higher than the second voltage so as to have a large portion of the first conductive type current conducting from the cathode through the active region to the metalized anode. ### Claim 14 (depends on 13) The current leakage protecting method according to claim 13, further comprising setting the third voltage to be higher than the second voltage so as to form a forward bias from the first contact region to the cathode, thereby having a small portion of the first conductive type current conducting from the cathode through the active region to the first contact region and the second contact region. ### Claim 15 (depends on 13) The current leakage protecting method according to claim 13, further comprising setting the third voltage to be lower than the second voltage so as to form a reverse bias from the first contact region to the cathode, thereby having a small portion of the first conductive type current conducting from the first contact region through the active region to the metalized anode.