CN-121985569-A - Super junction power device and preparation method thereof

CN121985569ACN 121985569 ACN121985569 ACN 121985569ACN-121985569-A

Abstract

The application discloses a super junction power device and a preparation method thereof, and belongs to the technical field of semiconductors. The super junction power device comprises a substrate, an epitaxial layer, a super junction structure, a first epitaxial column and a second epitaxial column, wherein the first epitaxial column and the second epitaxial column are alternately distributed along a first direction, the first epitaxial column is doped with first ions, the second epitaxial column is doped with second ions, the doping types of the first ions and the second ions are opposite, the interface of the first epitaxial column and the interface of the second epitaxial column comprise a first interface and a second interface which are sequentially connected towards the direction away from the substrate, the first interface faces towards the second epitaxial column, the second interface faces towards the first epitaxial column, the junction of the first epitaxial column and the second epitaxial column is provided with a diffusion area, the diffusion area is provided with the first ions and the second ions, and the difference value of the doping concentration of the first ions and the second ions in the diffusion area is unchanged in the first direction. The application can improve avalanche resistance, thereby improving the reliability of the device.

Inventors

ZHAO DONGYAN
FU ZHEN
WANG YUE
XIAO CHAO
FAN LIBO
TIAN JUN
HUANG JIABIN
ZHANG WENMIN

Assignees

北京智芯微电子科技有限公司
国网浙江省电力有限公司杭州供电公司
国家电网有限公司

Dates

Publication Date: 20260505
Application Date: 20251216

Claims (11)

1. A superjunction power device, comprising: A substrate; An epitaxial layer located on one side of the substrate in the thickness direction; the super-junction structure is positioned on the top of the epitaxial layer and comprises first epitaxial columns and second epitaxial columns which are alternately distributed along a first direction, wherein the first epitaxial columns are doped with first ions, the second epitaxial columns are doped with second ions, and the doping types of the first ions and the second ions are opposite; the interface of the first epitaxial column and the second epitaxial column comprises a first interface and a second interface which are sequentially connected in the direction away from the substrate, the first interface faces the direction of the second epitaxial column, the second interface faces the direction of the first epitaxial column, a diffusion area is arranged at the junction of the first epitaxial column and the second epitaxial column, the diffusion area is provided with first ions and second ions, and the difference value of doping concentrations of the first ions and the second ions in the diffusion area is unchanged in the first direction.
2. The super junction power device of claim 1, wherein the first epitaxial pillar comprises a first epitaxial sub-pillar and a second epitaxial sub-pillar connected in sequence in a direction away from the substrate, an interface of the first epitaxial sub-pillar and the second epitaxial pillar is the first interface, and an interface of the second epitaxial sub-pillar and the second epitaxial pillar is the second interface; the doping concentration of the first ions in the first epitaxial pillar and the second epitaxial sub-pillar are the same or different, and/or, The heights of the first epitaxial sub-pillars and the second epitaxial sub-pillars are the same or different.
3. The superjunction power device according to claim 2, wherein an angle between the first interface and a bottom surface of the first epitaxial sub-column is inversely related to a doping concentration of the first ions in the first epitaxial sub-column, and/or, And an included angle between the second interface and the bottom surface of the second epitaxial sub-column is in negative correlation with the doping concentration of the first ions in the second epitaxial sub-column.
4. The super junction power device according to claim 1, wherein the second epitaxial column comprises a third epitaxial sub-column and a fourth epitaxial sub-column sequentially connected in a direction away from the substrate, an interface of the third epitaxial sub-column and the first epitaxial column is the first interface, and an interface of the fourth epitaxial sub-column and the first epitaxial column is the second interface; The doping concentration of the second ions in the third epitaxial pillar and the fourth epitaxial sub-pillar are the same or different, and/or, The third epitaxial pillar and the fourth epitaxial sub-pillar may have the same or different heights.
5. The superjunction power device according to claim 4, wherein an angle between the first interface and a bottom surface of the third epitaxial sub-column is inversely related to a doping concentration of the second ions in the third epitaxial sub-column, and/or, And an included angle between the second interface and the bottom surface of the fourth epitaxial sub-column is in negative correlation with the doping concentration of the second ions in the fourth epitaxial sub-column.
6. The superjunction power device according to claim 1, wherein the angle of inclination of the first interface and the second interface is the same or different.
7. The super junction power device according to any one of claims 1-6, wherein a contact region and a well region distributed along the first direction are arranged on top of the first epitaxial column, a source region is arranged in the well region, and the source region is connected with the contact region; the superjunction power device further includes: the grid structure is positioned on one side of the super junction structure, which is away from the substrate, and covers part of the source region, part of the second epitaxial column and a well region between the source region and the second epitaxial column; the source electrode is positioned on one side of the super junction structure, which is away from the substrate, and is connected with the contact area and the source area; and the drain electrode is positioned on one side of the substrate, which is away from the epitaxial layer, and is connected with the substrate.
8. The preparation method of the super junction power device is characterized by comprising the following steps of: Providing a substrate; Forming an epitaxial layer on one side of the thickness direction of the substrate, and forming a super junction structure on the top of the epitaxial layer, wherein the super junction structure comprises first epitaxial columns and second epitaxial columns which are alternately distributed along a first direction, the first epitaxial columns are doped with first ions, the second epitaxial columns are doped with second ions, and the doping types of the first ions and the second ions are opposite; the interface of the first epitaxial column and the second epitaxial column comprises a first interface and a second interface which are sequentially connected in the direction away from the substrate, the first interface faces the direction of the second epitaxial column, the second interface faces the direction of the first epitaxial column, a diffusion area is arranged at the junction of the first epitaxial column and the second epitaxial column, the diffusion area is provided with first ions and second ions, and the difference value of doping concentrations of the first ions and the second ions in the diffusion area is unchanged in the first direction.
9. The method of manufacturing a superjunction power device according to claim 8, wherein the second epitaxial column comprises a third epitaxial sub-column and a fourth epitaxial sub-column; Forming a super junction structure on the top of the epitaxial layer, including: Forming a plurality of first grooves which are distributed at intervals along the first direction on the top of the epitaxial layer, wherein the groove walls of the first grooves incline outwards; Forming a first initial epitaxial column in the first groove, and forming a second initial epitaxial column by an epitaxial layer between adjacent first initial epitaxial columns; Etching the top of the second initial epitaxial column and the top edge of the first initial epitaxial column to form a second groove, wherein the groove wall of the second groove is inclined outwards, the etched first initial epitaxial column forms the first epitaxial column, and the etched second initial epitaxial column forms the third epitaxial sub-column; And forming a fourth epitaxial sub-column in the second groove, wherein the interface between the fourth epitaxial sub-column and the first epitaxial column is the second interface.
10. The method of manufacturing a superjunction power device according to claim 8, wherein the epitaxial layer comprises a first epitaxial sub-layer and a second epitaxial sub-layer, the first epitaxial column comprises a first epitaxial sub-column and a second epitaxial sub-column, and the second epitaxial column comprises a third epitaxial sub-column and a fourth epitaxial sub-column; forming an epitaxial layer on one side of the substrate in the thickness direction, and forming a super junction structure on the top of the epitaxial layer, wherein the method comprises the following steps: Forming a first epitaxial sub-layer on one side of the substrate in the thickness direction; forming a plurality of third grooves which are distributed at intervals along the first direction on the top of the first epitaxial sub-layer, wherein the groove walls of the third grooves incline outwards; Forming a first epitaxial sub-column in the third groove, wherein a first epitaxial sub-layer between adjacent first epitaxial sub-columns forms a third epitaxial sub-column, and the interface between the third epitaxial sub-column and the first epitaxial sub-column is the first interface; Forming a second epitaxial sub-layer covering the first epitaxial sub-column and the third epitaxial sub-column; And forming second epitaxial sub-columns and fourth epitaxial sub-columns which are alternately distributed along the first direction in the second epitaxial sub-layer, wherein the second epitaxial sub-columns are positioned at the top of the first epitaxial sub-columns, the fourth epitaxial sub-columns are positioned at the top of the third epitaxial sub-columns, and the interface between the second epitaxial sub-columns and the fourth epitaxial sub-columns is the second interface.
11. The method for manufacturing a super junction power device according to claim 10, wherein doping types of the second epitaxial sub-layer and the first epitaxial sub-layer are the same, the forming of the second epitaxial sub-pillars and the fourth epitaxial sub-pillars in the second epitaxial sub-layer, which are alternately distributed along the first direction, includes: forming a plurality of first openings in the second epitaxial sub-layer, wherein the first openings are distributed at intervals along the first direction, are positioned at the top of the first epitaxial sub-column and penetrate through the second epitaxial sub-layer, and the side walls of the first openings are inclined inwards; forming the second epitaxial sub-pillars in the first openings, wherein a second epitaxial sub-layer between adjacent second epitaxial sub-pillars forms the fourth epitaxial sub-pillars; Or alternatively The doping types of the second epitaxial sub-layer and the first epitaxial sub-layer are opposite, the forming the second epitaxial sub-pillars and the fourth epitaxial sub-pillars in the second epitaxial sub-layer, which are alternately distributed along the first direction, includes: forming a plurality of second openings in the second epitaxial sub-layer, wherein the second openings are distributed at intervals along the first direction, are positioned at the top of the third epitaxial sub-column, penetrate through the second epitaxial sub-layer, and are inclined outwards; and forming fourth epitaxial sub-pillars in the second openings, wherein second epitaxial sub-layers between adjacent fourth epitaxial sub-pillars form the second epitaxial sub-pillars.

Description

Super junction power device and preparation method thereof Technical Field The application belongs to the technical field of semiconductors, and relates to a super junction power device and a preparation method thereof. Background The super junction power device has the characteristics of small area, high current conducting capacity and the like. However, in the non-clamping inductive load process, a great amount of heat is generated because the device bears high voltage and high current at the same time, and the superjunction power device has serious heat concentration effect due to small area, so that the heat failure is easy to occur, the avalanche tolerance is reduced, and the reliability of the device is reduced. Disclosure of Invention The present application aims to solve at least one of the technical problems existing in the prior art. Therefore, the application provides the super junction power device and the preparation method thereof, which can improve avalanche tolerance and further improve device reliability. In a first aspect, the present application provides a superjunction power device, comprising: A substrate; An epitaxial layer located on one side of the substrate in the thickness direction; the super-junction structure is positioned on the top of the epitaxial layer and comprises first epitaxial columns and second epitaxial columns which are alternately distributed along a first direction, wherein the first epitaxial columns are doped with first ions, the second epitaxial columns are doped with second ions, and the doping types of the first ions and the second ions are opposite; the interface of the first epitaxial column and the second epitaxial column comprises a first interface and a second interface which are sequentially connected in the direction away from the substrate, the first interface faces the direction of the second epitaxial column, the second interface faces the direction of the first epitaxial column, a diffusion area is arranged at the junction of the first epitaxial column and the second epitaxial column, the diffusion area is provided with first ions and second ions, and the difference value of doping concentrations of the first ions and the second ions in the diffusion area is unchanged in the first direction. According to the super junction power device, the interface of the first epitaxial column and the second epitaxial column comprises the first interface and the second interface which are sequentially connected in the direction away from the substrate, the first interface faces the direction of the second epitaxial column, and the second interface faces the direction of the first epitaxial column, so that the width of the first epitaxial column is gradually increased and then gradually reduced, the difference value of the doping concentration of the first ions and the doping concentration of the second ions in the diffusion area at the interface of the first epitaxial column and the second epitaxial column is unchanged in the first direction, the super junction interface is in non-gradual gradient doping distribution, the critical breakdown electric field is improved, the avalanche breakdown voltage of the device is enhanced, the equivalent doping concentration of the device under the condition of high current is improved, the peak value of the electric field in the device is prevented from being transferred in advance, the avalanche current of the device is effectively improved, and the reliability of the device is improved. According to one embodiment of the application, the first epitaxial column comprises a first epitaxial sub-column and a second epitaxial sub-column which are sequentially connected towards the direction away from the substrate, the interface between the first epitaxial sub-column and the second epitaxial column is the first interface, and the interface between the second epitaxial sub-column and the second epitaxial column is the second interface; the doping concentration of the first ions in the first epitaxial pillar and the second epitaxial sub-pillar are the same or different, and/or, The heights of the first epitaxial sub-pillars and the second epitaxial sub-pillars are the same or different. According to one embodiment of the application, the angle between the first interface and the bottom surface of the first epitaxial sub-column is inversely related to the doping concentration of the first ions in the first epitaxial sub-column, and/or, And an included angle between the second interface and the bottom surface of the second epitaxial sub-column is in negative correlation with the doping concentration of the first ions in the second epitaxial sub-column. According to one embodiment of the application, the second epitaxial column comprises a third epitaxial sub-column and a fourth epitaxial sub-column which are sequentially connected towards the direction away from the substrate, the interface between the third epitaxial sub-column and