Hybrid power diode

Abstract

The invention relates to a hybrid power diode, and belongs to the field of semiconductor power devices. The semiconductor device comprises a substrate region; the drift region is formed on the surface of the substrate region; the first charge balance region is formed on the surface of the drift region; the second charge balance region is formed on the surface of the drift region, and the first charge balance region and the second charge balance region are alternately arranged on the surface of the drift region; the second electrode metal region is formed at the top of the diode device; and the first electrode metal region is formed on the other surface of the substrate region. In addition, according to the mixed device type, the diode comprises a shielding injection region formed by injection in the charge balance region, or comprises an insulating dielectric layer and a polycrystalline semiconductor material which are filled in a groove in the charge balance region. While the surface doping concentration is improved, the shielding effect on an electric field is kept, the problem that the on-resistance and the on-voltage drop are increased due to narrowing of a current path can be effectively solved, and the situation that the leakage current is too large and the breakdown voltage is remarkably reduced can be prevented.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor power devices and relates to a hybrid power diode. Background Art

[0002] Power diodes are essential basic electronic components in power electronic systems and are one of the most widely used power semiconductor devices. Their main functions are rectification and freewheeling. Their basic structures include power PIN diodes and power Schottky barrier diodes. The requirements for power diodes in applications are low on-state voltage drop, high breakdown voltage, low leakage current, and fast switching speed. The above basic structures can only partially meet these requirements. For example, in power PIN diodes, two types of carriers participate in conduction, with high breakdown voltage and low leakage current, but slow switching speed, high on-state voltage drop under low current conditions and low on-state voltage drop under high current conditions; while in power Schottky barrier diodes, only one type of carrier participates in conduction, with fast switching speed, but low breakdown voltage and high leakage current, low on-state voltage drop under low current conditions and high on-state voltage drop under high current conditions.

[0003] In order to comprehensively utilize their advantages, people have proposed a hybrid power diode structure that includes both a PIN structure and a Schottky barrier structure, including a junction barrier Schottky diode (JBS) diode and a merged PIN Schottky (MPS) diode. The two hybrid power diodes are similar in structure. They both use adjacent PN junctions to wrap the Schottky contact to shield the electric field, thereby reducing the leakage of the Schottky barrier and increasing the breakdown voltage. However, although the PN junction protects the Schottky contact, it also occupies a part of the area, resulting in a narrower path for the current to flow; at the same time, the space charge region of the PN junction will further compress the current path, and the narrowing of the current path will increase the on-resistance and on-voltage drop of the power diode. Although increasing the doping concentration of the semiconductor region between the PN junctions and under the Schottky contact can alleviate the current path narrowing effect, this will reduce the shielding effect of the PN junction on the electric field, resulting in an increase in leakage current and a decrease in breakdown voltage.

[0004] In order to reduce the on-state voltage drop of the hybrid power diode without affecting the leakage current and the breakdown voltage, it is necessary to improve the current path narrowing effect caused by the introduction of the PN junction. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a hybrid power diode, which introduces a charge balance structure on the surface of the hybrid power diode and uses charge balance technology to increase the surface doping concentration while maintaining the shielding effect on the electric field to prevent excessive leakage current and a significant reduction in breakdown voltage.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A hybrid power diode, comprising:

[0008] a substrate region of a first conductivity type;

[0009] A drift region of the first conductivity type formed on the surface of the substrate region;

[0010] A first charge balance region of a first conductivity type formed on the surface of the drift region;

[0011] A second charge balance region of a second conductivity type is formed on the surface of the drift region; the first charge balance region and the second charge balance region are alternately arranged on the surface of the drift region;

[0012] A second electrode metal region is formed on the top of the diode device, wherein the second electrode metal region forms a Schottky contact with the first charge balance region;

[0013] A first electrode metal region is formed on the other surface of the substrate region.

[0014] As a preferred embodiment, the hybrid power diode further includes a shielding injection region, which is formed by injecting high-concentration impurities into the first charge balance region and the second charge balance region along an arrangement direction of the first charge balance region and the second charge balance region.

[0015] As a preferred embodiment, the hybrid power diode may not form a shielding injection region, but instead form grooves along the arrangement direction in the first charge balance region and the second charge balance region, fill the grooves with an insulating dielectric layer, and fill the insulating dielectric layer with polycrystalline semiconductor material to form a polycrystalline semiconductor region.

[0016] The insulating dielectric layer, the polycrystalline semiconductor region and the first charge balance region constitute a trench metal-oxide-semiconductor structure, and the second electrode metal region and the trench metal-oxide-semiconductor structure form a trench metal-oxide-semiconductor barrier Schottky diode.

[0017] The beneficial effect of the present invention is that the present invention increases the surface doping concentration while maintaining the shielding effect on the electric field by introducing a surface charge balance structure. Compared with the conventional hybrid power diode structure, the present invention can effectively alleviate the problem of increased on-resistance and on-voltage drop caused by the narrowing of the current path, and can prevent excessive leakage current and significant reduction in breakdown voltage. The hybrid power diode proposed by the present invention is suitable for high-efficiency power electronic circuits and systems.

[0018] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 A schematic diagram of the structure of a hybrid power diode provided by an embodiment of the present invention;

[0021] Figure 2 A schematic structural diagram of a hybrid power diode provided in another embodiment of the present invention.

[0022] Figure numerals: 1 - first electrode metal region; 2 - second electrode metal region; 3 - first charge balance region; 4 - drift region; 5 - substrate region; 6 - second charge balance region; 7 - shielding injection region; 8 - insulating dielectric layer; 9 - polycrystalline semiconductor region. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0024] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0025] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] The present invention proposes a hybrid power diode structure, which introduces a charge balancing structure to alleviate the current path narrowing effect and alleviate the increase in on-resistance and on-voltage drop caused by the narrowing of the current path, thereby reducing the on-voltage drop of the hybrid power diode.

[0027] like Figure 1 The hybrid power diode provided by an embodiment of the present invention is shown, and its structure includes:

[0028] A semiconductor heavily doped substrate region 5 of the first conductivity type;

[0029] A first electrode metal region 1 is located below the substrate region 5, and the substrate region 5 is in contact with the first electrode metal region 1;

[0030] A semiconductor lightly doped drift region 4 of the first conductivity type is located on the substrate region 5, and the substrate region 5 is in contact with the drift region 4;

[0031] A first charge balance region 3 of a semiconductor of a first conductivity type and a second charge balance region 6 of a semiconductor of a second conductivity type are located above the drift region 4, wherein the first charge balance region 3 and the second charge balance region 6 are alternately arranged on the surface of the drift region 4, their side surfaces are directly in contact with each other to form a charge balance structure, and their bottom surfaces are in contact with the top surface of the drift region 4;

[0032] A heavily doped semiconductor shielding injection region 7 of the second conductivity type located inside the first charge balance region 3 and the second charge balance region 6, wherein the shielding injection region 7 is formed by injecting impurities into the first charge balance region 3 and the second charge balance region 6;

[0033] The second electrode metal region 2 is located on the top of the diode device, and covers the surfaces of the shielding injection region 7 , the first charge balance region 3 , and the second charge balance region 6 , wherein the second electrode metal region 2 forms a Schottky contact with the first charge balance region 3 .

[0034] In this embodiment, a charge balance region is introduced on the surface of the hybrid power diode to form a charge balance structure, and the surface doping concentration is increased by using the charge balance technology, while maintaining the shielding effect on the electric field to prevent excessive leakage current and significant reduction in breakdown voltage. The increase in surface doping concentration can effectively alleviate the problem of increased on-resistance and on-voltage drop caused by the narrowing of the current path.

[0035] When the first conductivity type is N type, the second conductivity type is P type, the first electrode is a cathode, and the second electrode is an anode; when the first conductivity type is P type, the second conductivity type is N type, the first electrode is an anode, and the second electrode is a cathode.

[0036] The semiconductor region may be made of silicon, or may be made of germanium, gallium arsenide, gallium nitride, silicon carbide, gallium oxide, diamond, or aluminum nitride.

[0037] In another embodiment of the present invention, part of the structure of the hybrid power diode is modified, such as Figure 2 As shown, the semiconductor shielding injection region 7 of the second conductivity type located in the charge balance structure is replaced by a trench to form a trench MOS Barrier Schottky diode (TMBS). Specifically, a plurality of spaced trenches are first formed in the first charge balance region 3 and the second charge balance region 6 (these trenches are formed at the positions of the original shielding injection region 7), and the trenches in the first charge balance region 3 and the second charge balance region 6 are aligned with each other to form a plurality of long straight trenches; then, an insulating dielectric layer 8 is filled in the trench, and a typical material is silicon dioxide, and a polycrystalline semiconductor material is filled in the insulating dielectric layer 8 to form a polycrystalline semiconductor region 9, so that the first charge balance region 3, the insulating dielectric layer 8, and the polycrystalline semiconductor region 9 constitute a trench metal-oxide-semiconductor structure. The second electrode metal region 2 and the trench metal-oxide-semiconductor structure form a barrier Schottky diode.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A hybrid power diode, characterized in that: It includes: a substrate region of a first conductivity type; A drift region of the first conductivity type formed on the surface of the substrate region; a charge balance region formed on the surface of the drift region; A second electrode metal region is formed on the top of the diode device, wherein the second electrode metal region forms a Schottky contact with the first charge balance region; A first electrode metal region is formed on the other surface of the substrate region.

2. The hybrid power diode according to claim 1, characterized in that: The charge balance region includes a first charge balance region and a second charge balance region alternately arranged on the surface of the drift region, the first charge balance region is of a first conductivity type, and the second charge balance region is of a second conductivity type.

3. The hybrid power diode according to claim 1 or 2, characterized in that: The hybrid power diode further includes a shielding injection region of a second conductivity type, wherein the shielding injection region is formed by injecting high-concentration impurities into the first charge balance region and the second charge balance region along the arrangement direction of the first charge balance region and the second charge balance region.

4. The hybrid power diode according to claim 1 or 2, characterized in that: The hybrid power diode also includes a groove formed along the arrangement direction in the first charge balance region and the second charge balance region, the groove is filled with an insulating dielectric layer, and the insulating dielectric layer is filled with polycrystalline semiconductor material to form a polycrystalline semiconductor region; the first charge balance region, the insulating dielectric layer, the polycrystalline semiconductor region and the second electrode metal region form a trench metal-oxide-semiconductor Schottky barrier diode.

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