CN116364748A - semiconductor diode - Google Patents

Abstract

The invention belongs to the technical field of semiconductor power devices, and particularly discloses a semiconductor diode, which comprises an n-type semiconductor layer; an anode metal layer over the n-type semiconductor layer; a plurality of alternately spaced n-type and p-type pillars within the n-type semiconductor layer; a p-type body region at the top of the p-type column; a low current carrier region, wherein the p-type body region in the low current carrier region and the anode metal layer form a p-type Schottky diode; and a p-type contact region is arranged in the p-type body region in the high current carrier region, and ohmic contact is formed between the p-type contact region and the anode metal layer.

Description

semiconductor diode

technical field

The invention belongs to the technical field of semiconductor power devices, in particular to a semiconductor diode.

Background technique

Traditional semiconductor diodes have a large chip area and low current density. At present, super junction structures are usually added to semiconductor diodes to increase chip current density and reduce chip area. However, the minority carriers stored in the unit area of conventional super junction semiconductor diodes Too much, and the sudden change in voltage due to the two-dimensional depletion effect, and the reverse recovery softness is too low, resulting in too much overshoot voltage during the reverse recovery process.

Contents of the invention

In view of this, the purpose of the present invention is to provide a semiconductor diode to reduce the sudden change in voltage caused by the two-dimensional depletion effect of the semiconductor diode with super junction structure.

In order to achieve the above-mentioned purpose of the present invention, the present invention provides a kind of semiconductor diode, comprising:

n-type semiconductor layer;

an anode metal layer overlying the n-type semiconductor layer;

a plurality of alternately spaced n-type columns and p-type columns located in the n-type semiconductor layer;

a p-type body region on top of the p-type pillar;

a low-carrier region, the p-type body region and the anode metal layer in the low-carrier region form a p-type Schottky diode;

In the high-carrier region, a p-type contact region is provided in the p-type body region in the high-carrier region, and the p-type contact region forms an ohmic contact with the anode metal layer.

Optionally, the n-type columns in the high-carrier region and the anode metal layer form an n-type Schottky diode.

Optionally, the low-carrier region is located at an edge region of the active region of the semiconductor diode, and the high-carrier region is located at a middle region of the active region of the semiconductor diode.

Optionally, the width of the p-type body region is larger than the width of the p-type pillar.

The semiconductor diode of the present invention is formed with a low-carrier region and a high-carrier region. During the reverse recovery process, the carriers in the low-carrier region will be extracted first, and then the carriers in the high-carrier region will be extracted. carriers, which can gradually increase the reverse withstand voltage, avoiding the voltage mutation caused by two-dimensional depletion; further, an n-type Schottky diode is formed in the high-carrier region, and multiple carriers are injected into the semiconductor diode. , can reduce the number of minority carriers stored in the pn junction under the ohmic contact area, and reduce the reverse recovery peak current.

Description of drawings

In order to illustrate the technical solutions of the exemplary embodiments of the present invention more clearly, the following briefly introduces the drawings used in describing the embodiments.

Fig. 1 is a schematic cross-sectional structure diagram of the first embodiment of the semiconductor diode provided by the present invention.

Detailed ways

The technical solution of the present invention will be fully described below in a specific manner with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, not all, embodiments of the present invention. At the same time, in order to clearly illustrate the specific implementation of the present invention, the schematic diagrams listed in the accompanying drawings of the specification magnify the thickness of the layers and regions described in the present invention, and the listed figures do not represent the actual size.

Fig. 1 is the schematic cross-sectional structure diagram of the first embodiment of semiconductor diode provided by the present invention, as shown in Fig. 1, semiconductor diode of the present invention comprises n-type semiconductor layer 20, and n-type semiconductor layer 20 is usually formed on n-type substrate 10 or more.

A plurality of n-type pillars 22 and p-type pillars 21 are arranged alternately in the n-type semiconductor layer 20 , and a charge-balanced superjunction structure is formed between the n-type pillars 22 and the p-type pillars 21 . For the p-type body region 23 located on the top of the p-type pillar 21 , the width of the p-type body region 23 is preferably larger than the width of the p-type pillar 21 .

The anode metal layer 25 and insulating layer 26 located on the n-type semiconductor layer 20 function as electrical insulation.

The semiconductor diode of the present invention includes a low-carrier region 31 and a high-carrier region 32. In the low-carrier region 31: the p-type body region 23 is in contact with the anode metal layer 25 to form a p-type Schottky diode Structure; in the high-carrier region 32: a p-type contact region 24 is provided in the p-type body region 23, and the p-type contact region 24 is in contact with the anode metal layer 25 to form an ohmic contact structure. Preferably, the low-carrier region 31 is located at the edge region of the active region of the semiconductor diode, and the high-carrier region 32 is located at the middle region of the active region of the semiconductor diode. Wherein, the low-carrier region 31 may be located in a part of the edge region of the active region, or the entire edge region may be the low-carrier region 31, for example, the low-carrier region 31 may be located in the high-carrier region 32 One side or two sides of , or the low-carrier region 31 surrounds the high-carrier region 32 . Exemplarily, FIG. 1 only shows the structure at the adjacent positions of the low-carrier region 31 and the high-carrier region 32, but does not show the structure of the low-carrier region 31 and the high-carrier region 32 globally. structure.

In the semiconductor diode of the present invention, in the reverse recovery process, the carriers in the low-carrier region will be extracted first, and then the carriers in the high-carrier region will be extracted, which can gradually increase the reverse withstand voltage. Voltage mutations due to two-dimensional depletion are avoided.

In the semiconductor diode of the present invention, in the high-carrier region 32, the n-type column 22 can also be contacted with the anode metal layer 25 to form an n-type Schottky diode, which can inject many carriers into the semiconductor diode and reduce the ohmic contact area The number of minority carriers stored in the pn junction below reduces the reverse recovery peak current.

The above specific implementation methods and examples are specific support for the technical ideas of the present invention, and cannot limit the protection scope of the present invention. Any equivalent changes or equivalents made on the basis of the technical solutions according to the technical ideas proposed in the present invention All changes still belong to the protection scope of the technical solution of the present invention.

Claims (4)

1. A semiconductor diode, characterized in that it comprises: n-type semiconductor layer; an anode metal layer overlying the n-type semiconductor layer; a plurality of alternately spaced n-type columns and p-type columns located in the n-type semiconductor layer; a p-type body region on top of the p-type pillar; a low-carrier region, the p-type body region and the anode metal layer in the low-carrier region form a p-type Schottky diode; In the high-carrier region, a p-type contact region is provided in the p-type body region in the high-carrier region, and the p-type contact region forms an ohmic contact with the anode metal layer. 2. The semiconductor diode according to claim 1, wherein the n-type column in the high-carrier region and the anode metal layer form an n-type Schottky diode. 3. The semiconductor diode according to claim 1, wherein the low carrier region is located at the edge region of the active region of the semiconductor diode, and the high carrier region is located in the middle of the active region of the semiconductor diode area. 4. The semiconductor diode according to claim 1, wherein the width of the p-type body region is greater than the width of the p-type pillar.

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