Trench-gate insulated gate bipolar transistor (IGBT) and manufacturing method therefor

Abstract

The present application relates to a trench-gate insulated gate bipolar transistor (IGBT) and a manufacturing method therefor. The IGBT comprises: a collector region; a drift region; a body region; an emitter region; trench gate structures, which extend from the body region into the drift region, the trench gate structures being arranged in a grid pattern resembling the Chinese character "田" in a plan view; target trench structures, which extend from the body region into the drift region, wherein each target trench structure is located in each "inner square" section of the trench gate structures arranged in the grid pattern resembling the Chinese character "田" and is surrounded by the four sides of each "inner square" section, and the depth of each first trench is less than the depth of each second trench; a voltage-withstanding region of a second electrical conductivity type, wherein the voltage-withstanding region is located in the drift region below each second trench and surrounds the bottom of each second trench; and a target metal interconnect located above the body region and configured to connect to an emitter potential, wherein the target metal interconnect is connected to polysilicon, the emitter region and the body region by means of a contact hole therebelow. The trench gate structures in the present invention are arranged in a grid pattern resembling the Chinese character "田" in the plan view; therefore, the density of the trench gate structures per unit of area is relatively high, and thus a device can obtain a relatively high current density.

Claims

1. A trench-gate insulated-gate bipolar transistor, characterized in that, Comprising: A collector region having a second conductivity type; A drift region having a first conductivity type, located on the collector region; The first conductivity type and the second conductivity type are opposite conductivity types; A body region having a second conductivity type, located on the drift region; An emitter region having a first conductivity type, located in the body region; A trench gate structure extending from the body region into the drift region, including a gate dielectric layer on the inner surface of a first trench and a gate electrode located in the first trench and surrounded by the gate dielectric layer; the trench gate structure is arranged in a "field" shape in a plane; A target trench structure extending from the body region into the drift region, located in each "square" of the "field"-shaped arranged trench gate structure and surrounded by each "square" on all four sides, including an insulating dielectric layer on the inner surface of a second trench and polysilicon located in the second trench and surrounded by the insulating dielectric layer; The depth of the first trench is less than the depth of the second trench; A breakdown voltage region having a second conductivity type, located in the drift region below the second trench and surrounding the bottom of the second trench; A target metal connection located above the body region for connecting to the emitter potential, and the target metal connection is electrically connected to the polysilicon, emitter region and body region through a contact hole below; 2. The trench gate insulated gate bipolar transistor according to claim 1, characterized in that, The width of the first trench is 0.2 to 0.4 micrometers.

3. The trench gate insulated gate bipolar transistor according to claim 1, characterized in that, The material of the gate electrode is polysilicon.

4. The trench gate insulated gate bipolar transistor according to claim 1, characterized in that, It further includes a buffer layer located between the collector region and the drift region.

5. The trench gate insulated gate bipolar transistor according to claim 4, characterized in that, The buffer layer has a first conductivity type.

6. The trench gate insulated gate bipolar transistor according to claim 5, characterized in that, The doping concentration of the buffer layer is greater than the doping concentration of the drift region.

7. The trench gate insulated gate bipolar transistor according to claim 1, characterized in that, It further includes an interlayer dielectric layer located above the body region, emitter region, trench gate structure and target trench structure and below the target metal connection, and the contact hole penetrates through the interlayer dielectric layer.

8. The trench gate insulated gate bipolar transistor according to claim 1, characterized in that, The materials of the gate dielectric layer and the insulating dielectric layer are silicon oxides.

9. The trench gate insulated gate bipolar transistor according to any one of claims 1-8, characterized in that, The first conductivity type is N-type and the second conductivity type is P-type.

10. A manufacturing method of a trench gate insulated gate bipolar transistor, comprising: Obtaining a substrate having a drift region of a first conductivity type; Forming a trench gate structure, a target trench structure and a breakdown voltage region of a second conductivity type in the drift region; The trench gate structure includes a gate dielectric layer on the inner surface of a first trench and a gate electrode located in the first trench and surrounded by the gate dielectric layer, and the trench gate structure is arranged in a "field" shape in a plane; The target trench structure is located in each "square" of the "field"-shaped arranged trench gate structure and surrounded by each "square" on all four sides. The target trench structure includes an insulating dielectric layer on the inner surface of a second trench and polysilicon located in the second trench and surrounded by the insulating dielectric layer. The depth of the first trench is less than the depth of the second trench; the breakdown voltage region is formed in the drift region below the second trench and surrounds the bottom of the second trench; the first conductivity type and the second conductivity type are opposite conductivity types; Doping the drift region to form a body region on the upper side surfaces of the trench gate structure and the target trench structure, and the body region has a second conductivity type; The body region is doped to form an emitter region of a first conductivity type in the body region; A contact hole is formed on the polysilicon, and the contact hole is filled with a conductive material that is electrically connected to the polysilicon, the emitter region and the body region; A target metal interconnect is formed on the contact hole; the target metal interconnect is electrically connected to the polysilicon, the emitter region and the body region through the contact hole; A current collector region is formed at the bottom of the substrate.

11. The method for manufacturing a trench gate insulated gate bipolar transistor according to claim 10, characterized in that, The step of forming a trench grid structure, a target trench structure, and a voltage-resistant region of the second conductivity type in the drift region includes: The second trench is formed by photolithography and etching; The insulating dielectric layer is formed on the inner surface of the second trench; The pressure-resistant zone is formed within the drift region below the second trench; Fill the second trench with polysilicon; The first trench is formed by photolithography and etching; A gate dielectric layer is formed on the inner surface of the first trench; A gate is formed in the first trench.

12. The method for manufacturing a trench gate insulated gate bipolar transistor according to claim 10, characterized in that, The step of forming a trench grid structure, a target trench structure, and a voltage-resistant region of the second conductivity type in the drift region includes: The second trench is formed by photolithography and etching; The pressure-resistant zone is formed within the drift region below the second trench; The insulating dielectric layer is formed on the inner surface of the second trench; Fill the second trench with polysilicon; The first trench is formed by photolithography and etching; A gate dielectric layer is formed on the inner surface of the first trench; A gate is formed in the first trench.

13. The method for manufacturing a trench gate insulated gate bipolar transistor according to claim 10, characterized in that, The step of forming a trench grid structure, a target trench structure, and a voltage-resistant region of the second conductivity type in the drift region includes: First, the trench grid structure is formed, and then the target trench structure and the pressure-resistant zone are formed.

14. The method for manufacturing a trench gate insulated gate bipolar transistor according to claim 10, characterized in that, The width of the first trench is 0.2 micrometers to 0.4 micrometers.

15. The method for manufacturing a trench gate insulated gate bipolar transistor according to claim 10, characterized in that, The step of forming a current collector region at the bottom of the substrate includes: The substrate is thinned on the back side; The second type of conductivity ions are implanted onto the back side of the substrate to form the current collecting region; The back metal is formed as the current collector.

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