CN210607275U - Groove type semiconductor power device with built-in Schottky structure - Google Patents

Abstract

The utility model provides a ditch slot type semiconductor power device of built-in schottky structure, including N type semiconductor substrate, its upper surface is opened there is the perpendicular slot of a plurality of, and slot inner wall and periphery set up the gate oxide layer, and the subsurface below between the slot forms N + injection layer, and the ditch inslot is filled up electrically conductive polycrystalline silicon, covers dielectric layer on slot top and the periphery, covers the metal level on the dielectric layer, and the metal level downwardly extending is downthehole to the pin, and N + injection layer below, form adjacent P + injection layer and P-injection layer between pin hole and the slot. The utility model discloses a forward pressure drop is little, and reverse recovery loss is low, and fast speed of closing is high, and reverse recovery curve is softer, and the reliability increases.

Description

Groove type semiconductor power device with built-in Schottky structure

Technical Field

The utility model relates to a semiconductor power device, especially a ditch slot type semiconductor power device of built-in schottky structure.

Background

As shown in fig. 1, a conventional semiconductor power device with a parasitic PN junction diode is provided, the semiconductor power device has a parasitic PN junction diode connected in parallel with the semiconductor power device, an anode of the parasitic diode is connected to a body region and a source of the power device, and a cathode of the parasitic diode is connected to a drain of the power device, so that the power device is often used for freewheeling or clamping voltage, when freewheeling or clamping voltage, the parasitic diode is in forward conduction, a forward voltage drop of the parasitic diode is generally about 0.8V, and when the MOS device operates in a diode freewheeling mode, a forward voltage drop of the MOS device is high, and power consumption is high. And the parasitic diode is the same as a common diode, and conduction is carried out by minority carriers, so that after the freewheeling mode is finished, the MOS device has a reverse recovery process of the parasitic diode, and the PN junction diode has longer reverse recovery time, thereby reducing the switching speed and increasing the power consumption, and the recovery curve is harder, so that the reliability of the diode is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model provides a technical problem provide a ditch slot type semiconductor power device of built-in schottky structure, through built-in schottky diode structure, electrically conductive by many son, with the parallelly connected use of power device, when the afterflow, parasitic diode's minority carrier diffusion reduces, reverse recovery time greatly reduced greatly.

Realize the utility model discloses the technical solution of purpose does:

a trench type semiconductor power device with a built-in Schottky structure comprises an N-type semiconductor substrate, wherein the upper surface of the N-type semiconductor substrate is defined as a first surface, a plurality of trenches in the vertical direction are formed in the first surface, gate oxide layers are arranged on the inner wall of each trench and the first surface on the periphery of each trench, and an N + injection layer is formed below the first surface between the trenches; the groove is filled with conductive polysilicon, and insulating medium layers are covered above the groove and the periphery of the groove; the groove and the insulating medium layer above the periphery of the groove are covered with metal layers, the metal layers extend downwards into the lead holes, the lead holes penetrate through the insulating medium layer, the gate oxide layer at the periphery of the groove and the N + injection layer at the periphery of the groove to the middle of the N-type semiconductor substrate, and adjacent P + injection layers and P-injection layers are formed below the N + injection layers and between the lead holes and the groove, wherein the P + injection layers are close to the lead holes, and the P-injection layers are close to the groove.

The utility model adopts the above technical scheme to compare with prior art, have following technological effect:

1. the utility model discloses a ditch slot type semiconductor power device of built-in schottky structure's forward pressure drop is little, and reverse recovery loss is low, and fast turn-off speed is high, and reverse recovery curve is softer, and the reliability increases.

2. The utility model discloses a ditch slot type semiconductor power device of built-in schottky structure adopts parallelly connected schottky diode, and it is electrically conductive by many son (electron), and uses with power device is parallelly connected, and when the afterflow, parasitic diode's minority carrier diffusion reduces greatly, reverse recovery time greatly reduced.

3. The utility model discloses a slot type semiconductor power device of built-in schottky structure simple structure, the reliability is high.

Drawings

Fig. 1 is a schematic diagram of a semiconductor power device with a parasitic PN junction diode.

Fig. 2 is a schematic structural diagram of a trench semiconductor power device with a built-in schottky structure.

Reference signs mean: 1: n-type semiconductor substrate, 2: groove, 3: gate oxide, 4: conductive polysilicon, 5: insulating dielectric layer, 6: n + injection layer, 7: p + implant layer, 8: p-implant layer, 9: metal layer, 10: and a lead hole.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.

A trench type semiconductor power device with a built-in Schottky structure is shown in fig. 2 and comprises an N-type semiconductor substrate 1, wherein the upper surface of the N-type semiconductor substrate 1 is defined as a first surface. The first surface is provided with a plurality of grooves 2 in the vertical direction, the inner walls of the grooves 2 and the first surface at the periphery of the grooves are provided with gate oxide layers 3, and N + injection layers 6 are formed below the first surfaces among the grooves 2.

The groove 2 is filled with conductive polysilicon 4, and an insulating medium layer 5 covers the upper part of the groove 2 and the upper part of the periphery of the groove.

The trench 2 and the insulating dielectric layer 5 above the periphery thereof are covered with a metal layer 9, and the metal layer 9 extends downwards into the lead hole 10. The lead wire hole 10 penetrates through the insulating medium layer 5, the gate oxide layer 3 on the periphery of the groove 2 and the N + injection layer 6 on the periphery of the groove 2 to the middle of the N-type semiconductor substrate 1. And a P + injection layer 7 and a P-injection layer 8 which are adjacent to each other are formed below the N + injection layer 6 and between the lead hole 10 and the groove 2, wherein the P + injection layer 7 is close to the lead hole 10, and the P-injection layer 8 is close to the groove 2.

Compared with a semiconductor power device with a parasitic PN junction diode, the groove type semiconductor power device with the built-in Schottky structure reduces forward voltage drop and reverse recovery loss, increases fast turn-off speed and reverse recovery softness, and increases reliability. The parallel Schottky diode is conducted by multiple electrons and is used in parallel with a power device, the minority carrier diffusion of a parasitic diode is greatly reduced when current flows, and the reverse recovery time is greatly reduced.

The manufacturing method of the groove type semiconductor power device with the built-in Schottky structure comprises the following steps:

step 1, providing an N-type semiconductor substrate 1 with two opposite surfaces, and defining the upper surface of the N-type semiconductor substrate 1 as a first surface;

step 2, etching the first surface to form a groove 2 in the vertical direction;

step 3, growing a gate oxide layer 3 on the first surface, wherein the gate oxide layer 3 covers the inner wall of the groove 2 and the first surface of the periphery of the groove;

step 4, depositing and etching the conductive polysilicon 4 to fill the conductive polysilicon 4 in the trench 2;

and 5: injecting P-type impurities from the gate oxide layer 3 above the first surface and annealing, and then injecting N-type impurities from the gate oxide layer 3 and annealing;

step 6: depositing an insulating medium layer 5 above the trench 2 and above the periphery thereof;

and 7: defining a lead hole 10 area through hole photoetching, etching and penetrating an insulating medium layer 5, a gate oxide layer 3 at the periphery of a groove 2, and an N + injection layer 6 at the periphery of the groove 2 to the middle part of an N-type semiconductor substrate 1 in sequence to form a lead hole 10, depositing a metal layer 9 in the lead hole 10 and at the periphery thereof, wherein the metal layer 9 is filled in the lead hole 10 and covers the insulating medium layer 5 at the periphery of the lead hole 10, the N + injection layer 6 is formed below a first surface between the grooves 2, the adjacent P + injection layer 7 and the P-injection layer 8 are formed below the N + injection layer 6 and between the lead hole 10 and the groove 2, the P + injection layer 7 is close to the lead hole 10, and the P-injection layer 8 is close to the groove 2.

The foregoing is only a part of the embodiments of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements can be made without departing from the principles of the present invention, and these improvements should be regarded as the protection scope of the present invention.

Claims (1)

1. A trench type semiconductor power device with a built-in Schottky structure is characterized by comprising an N-type semiconductor substrate (1), wherein the upper surface of the N-type semiconductor substrate (1) is defined as a first surface, a plurality of vertical trenches (2) are formed in the first surface, gate oxide layers (3) are arranged on the inner wall of each trench (2) and the first surface on the periphery of the trench, and an N + injection layer (6) is formed below the first surface between the trenches (2);

the groove (2) is filled with conductive polysilicon (4), and insulating medium layers (5) are covered above the groove (2) and the periphery of the groove; the groove (2) and the insulating medium layer (5) above the periphery of the groove are covered with a metal layer (9), the metal layer (9) extends downwards into a lead hole (10), the lead hole (10) penetrates through the insulating medium layer (5), the gate oxide layer (3) on the periphery of the groove (2) and the N + injection layer (6) on the periphery of the groove (2) until the middle of the N-type semiconductor substrate (1), the N + injection layer (6) is arranged below the lead hole (10) and between the lead hole (10) and the groove (2) to form an adjacent P + injection layer (7) and a P-injection layer (8), wherein the P + injection layer (7) is close to the lead hole (10), and the P-injection layer (8) is close to the groove (2).

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