CN210607276U

CN210607276U - Groove type power device based on Schottky structure

Info

Publication number: CN210607276U
Application number: CN201921935608.8U
Authority: CN
Inventors: 丁磊; 侯宏伟; 顾挺
Original assignee: Jiangsu Xiechang Electronic Technology Co ltd; Zhangjiagang Kaicheng Software Technology Co ltd; ZHANGJIAGANG CASS SEMICONDUCTOR CO Ltd
Current assignee: Jiangsu Xiechang Electronic Technology Co ltd; Zhangjiagang Kaicheng Software Technology Co ltd; ZHANGJIAGANG CASS SEMICONDUCTOR CO Ltd
Priority date: 2019-11-11
Filing date: 2019-11-11
Publication date: 2020-05-22
Anticipated expiration: 2029-11-11

Abstract

The utility model provides a slot type power device based on schottky structure, including N type semiconductor substrate, its upper surface is opened there is the perpendicular slot of a plurality of, slot inner wall and periphery set up the gate oxide, the subsurface below between the slot forms the N + injection layer, the ditch inslot is filled up electrically conductive polycrystalline silicon, cover dielectric layer on slot top and the periphery, cover the metal level on the dielectric layer, the metal level downwardly extending is downthehole to the pin, form the P + injection layer of fan-shaped between pin hole and the N + injection layer, N + injection layer below, form the P-injection layer of fan-shaped between slot and the P + injection layer. 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 power device based on Schottky structure

Technical Field

The utility model relates to a semiconductor power device, especially a slot type power device based on 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 slot type power device based on schottky structure, through 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 power device based on a 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, and 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 reach the upper part of the N-type semiconductor substrate; a fan-shaped P + injection layer is formed between the lead hole and the N + injection layer, and the P + injection layer is contacted with the lead hole and the N + injection layer; a fan-shaped P-injection layer is formed below the N + injection layer and between the groove and the P + injection layer, and the P-injection layer is contacted with the N + injection layer, the groove and the P + injection layer.

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 power device forward voltage drop based on schottky structure is little, and reverse recovery loss is low, and fast closing speed is high, and reverse recovery curve is softer, and the reliability increases.

2. The utility model discloses a slot type power device based on 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 power device based on 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 power device based on a Schottky structure comprises 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 trenches 2 in the vertical direction are formed in the first surface, gate oxide layers 3 are arranged on the inner walls of the trenches 2 and the first surface on the periphery of the inner walls, 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 thereof; 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, and 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 to reach the upper part of the N-type semiconductor substrate 1.

A fan-shaped P + injection layer 7 is formed between the lead hole 10 and the N + injection layer 6, and the P + injection layer 7 is contacted with the lead hole 10 and the N + injection layer 6; a fan-shaped P-injection layer 8 is formed below the N + injection layer 6 and between the groove 2 and the P + injection layer 7, and the P-injection layer 8 is contacted with the N + injection layer 6, the groove 2 and the P + injection layer 7.

Compared with a semiconductor power device of a parasitic PN junction diode, the groove type power device based on the 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 trench type power device based on the 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: and defining the area of the lead hole 10 by hole photoetching, and etching and penetrating 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 upper part of the N-type semiconductor substrate 1 in sequence to form the deep lead hole 10. Depositing a metal layer 9 in and around the lead hole 10, wherein the metal layer 9 fills the lead hole 10 and covers the insulating medium layer 5 around the lead hole 10, forming an N + injection layer 6 under the first surface around the trench 2, forming a fan-shaped P + injection layer 7 between the lead hole 10 and the N + injection layer 6, and the P + injection layer 7 is in contact with both the lead hole 10 and the N + injection layer 6; a fan-shaped P-injection layer 8 is formed below the N + injection layer 6 and between the groove 2 and the P + injection layer 7, and the P-injection layer 8 is contacted with the N + injection layer 6, the groove 2 and the P + injection layer 7.

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. A trench type power device based on a 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 trenches (2) in the vertical direction 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; a metal layer (9) covers the groove (2) and the insulating medium layer (5) above the periphery of the groove, the metal layer (9) extends downwards into a lead hole (10), and 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) to the upper part of the N-type semiconductor substrate (1);

a fan-shaped P + injection layer (7) is formed between the lead hole (10) and the N + injection layer (6), and the P + injection layer (7) is contacted with the lead hole (10) and the N + injection layer (6); a fan-shaped P-injection layer (8) is formed below the N + injection layer (6) and between the groove (2) and the P + injection layer (7), and the P-injection layer (8) is contacted with the N + injection layer (6), the groove (2) and the P + injection layer (7).