CN210325812U

CN210325812U - Fast recovery diode

Info

Publication number: CN210325812U
Application number: CN201921029362.8U
Authority: CN
Inventors: 和峰; 金锐; 刘钺杨; 刘江; 董少华; 温家良; 吴军民; 潘艳
Original assignee: Global Energy Interconnection Research Institute
Current assignee: Global Energy Interconnection Research Institute
Priority date: 2019-07-03
Filing date: 2019-07-03
Publication date: 2020-04-14
Anticipated expiration: 2029-07-03

Abstract

The utility model provides a fast recovery diode, which comprises a substrate, an N + cathode region, a P + anode region, a life control doped layer, a P + doped layer, an anode electrode and a cathode electrode; the P + doped layer is positioned inside the life control doped layer, and the life control doped layer is positioned inside the P + anode region; the anode side electrode and the cathode side electrode are respectively positioned on the front surface and the back surface of the substrate; the P + anode region is positioned on the front surface of the substrate and close to the anode side electrode, and the N + cathode region is positioned on the back surface of the substrate and close to the cathode side electrode. The utility model reduces the reverse blocking leakage current and the forward conduction voltage drop, further reduces the loss of the fast recovery diode, and prolongs the service life; and through the utility model provides a life-span control doping layer can effectively improve the voltage temperature coefficient of fast recovery diode.

Description

Fast recovery diode

Technical Field

The utility model relates to a power semiconductor technology field, concretely relates to fast recovery diode.

Background

As a common power semiconductor switching device, a Fast Recovery Diode (FRD) is often used in inverse parallel with an Insulated Gate Bipolar Transistor (IGBT) in various fields such as home appliances, electric vehicles, and rail locomotives due to its characteristics of good switching characteristics and short reverse Recovery time, and is widely applied to high-voltage devices such as converter valves and circuit breakers, particularly in power systems. The structure of the common diode is that a P-type semiconductor and an N-type semiconductor are directly contacted to form a PN junction, and an intrinsic semiconductor i area is added between the P-type silicon material and the N-type silicon material of the common diode to form a P-i-N silicon chip of the fast recovery diode suitable for the power system. Wherein: the method for preparing the intrinsic semiconductor i-region is mainly to form a low-concentration N-region on a P-type layer and an N-type layer, so that the N-region can be approximately regarded as the intrinsic semiconductor i-region compared with the P-type region and the N-type region, and the fast recovery diode structure and the doping distribution are schematically shown in FIG. 1. At present, a common fast recovery diode generally uses a global life control technology, such as a heavy metal diffusion technology, to form a life control region from top to bottom in the diode, and regulate and control the whole-region carrier life of a P region, an i region and an N region of the diode, so as to achieve the purposes of optimizing carrier distribution and optimizing performance parameters of the diode.

Under the forward conduction state of the fast recovery diode, electrons and holes can be injected into an N-drift region of a high-resistance region, the carrier concentration is increased, a conductivity modulation effect is formed, the forward conduction voltage drop is reduced under the rated current condition, and the forward conduction loss is reduced. But due to the presence of global lifetime control the carrier concentration of the N-drift region is generally kept at a relatively low level, i.e. the loss of the fast recovery diode in the forward conducting state is relatively high. In the active region, the N-region of the low-doped drift region bears most of the electric field, a large number of electron-hole pairs are separated under the action of the electric field, electrons move to the cathode side at a high potential to form an electron current, and holes move to the anode side at a low potential to form a hole current, and the sum of the two forms a reverse leakage current, and the distribution schematic diagram of the reverse electric field of the fast recovery diode is shown in fig. 2. In particular, if a carrier lifetime control layer exists in the drift region, the defects forming the lifetime control layer generate more electrons and holes under the action of a reverse electric field, and the reverse leakage current further increases, resulting in a higher loss ratio of the fast recovery diode in a reverse blocking state.

SUMMERY OF THE UTILITY MODEL

In order to overcome the above-mentioned prior art in the forward conducting state and reverse blocking state under the loss ratio of fast recovery diode relatively high not enough, the utility model provides a fast recovery diode, fast recovery diode includes substrate, N + negative pole district, P + positive pole district, life-span control doped layer, P + doped layer, anode side electrode and cathode side electrode; the P + doped layer is positioned inside the life control doped layer, and the life control doped layer is positioned inside the P + anode region; the anode side electrode and the cathode side electrode are respectively positioned on the front surface and the back surface of the substrate; the P + anode region is positioned on the front surface of the substrate and close to the anode side electrode, and the N + cathode region is positioned on the back surface of the substrate and close to the cathode side electrode, so that the loss of the fast recovery diode in a forward conduction state and a reverse blocking state is reduced.

In order to achieve the purpose, the utility model adopts the following technical scheme:

in one aspect, the utility model provides a fast recovery diode, including substrate, N + negative pole district, P + positive pole district, life-span control doping layer, P + doping layer, anode side electrode and cathode side electrode;

the P + doped layer is positioned inside the life control doped layer, and the life control doped layer is positioned inside the P + anode region; the anode side electrode and the cathode side electrode are respectively positioned on the front surface and the back surface of the substrate; the P + anode region is positioned on the front surface of the substrate and close to the anode side electrode, and the N + cathode region is positioned on the back surface of the substrate and close to the cathode side electrode.

The lifetime control doping layer is formed by ion implantation.

The ion implantation times adopt a single step or multiple steps;

the ion implantation mode adopts a light ion implantation mode or a heavy ion implantation mode.

The concentration of the N + cathode region and the concentration of the P + anode region are both higher than that of the substrate, and the concentration of the P + doped layer is higher than that of the P + anode region.

The concentration of the substrate is 1E11cm^-3～1E15cm^-3The later degree is 100 um-600 um.

The concentration of the N + cathode region is 1E12cm^-3～1E23cm^-3And the depth of the N + cathode region is 20 um-100 um.

Concentration of the P + anode region 1E13cm^-3～1E22cm^-3And the depth of the P + anode region is 3um to 50 um.

Concentration of the P + doped layer 1E15cm^-3～1E30cm^-3And the depth of the P + doped layer is 1um to 2 um.

And the anode side electrode and the cathode side electrode are made of metal materials or semiconductor materials.

Compared with the closest prior art, the utility model provides a technical scheme has following beneficial effect:

the utility model provides a fast recovery diode includes substrate, N + negative pole district, P + positive pole district, life-span control doped layer, P + doped layer, anode side electrode and cathode side electrode; the P + doped layer is positioned inside the life control doped layer, and the life control doped layer is positioned inside the P + anode region; the anode side electrode and the cathode side electrode are respectively positioned on the front surface and the back surface of the substrate; the P + anode region is positioned on the front surface of the substrate and close to the anode side electrode, and the N + cathode region is positioned on the back surface of the substrate and close to the cathode side electrode, so that the loss of the fast recovery diode in a forward conduction state and a reverse blocking state is reduced;

the utility model provides a fast recovery diode can reduce electron and hole pass through defect energy level recombination's probability under the forward conduction state, has effectively improved carrier concentration in the N-drift region, has reduced the forward conduction pressure drop under the forward conduction state, has prolonged fast recovery diode's life-span;

through the utility model provides a life-span control doping layer can effectively improve the voltage temperature coefficient of fast recovery diode.

Drawings

FIG. 1 is a schematic diagram of a prior art fast recovery diode structure and doping profile;

FIG. 2 is a diagram illustrating a reverse electric field distribution of a fast recovery diode in the prior art;

fig. 3 is a schematic structural diagram of a fast recovery diode according to an embodiment of the present invention;

fig. 4 is a schematic diagram of doping concentration distribution and lifetime distribution of a fast recovery diode according to an embodiment of the present invention;

in the figure, 1, substrate, 2, N + cathode region, 3, P + anode region, 4, lifetime control doped layer, 5, P + doped layer, 6, anode side electrode, 7, cathode side electrode.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The embodiment of the utility model provides a fast recovery diode, its structure is shown in fig. 3, it includes substrate 1, N + negative pole district 2, P + positive pole district 3, life-span control doped layer 4, P + doped layer 5, anode side electrode 6 and cathode side electrode 7;

the P + doped layer 5 is positioned inside the life control doped layer 4, and the life control doped layer 4 is positioned inside the P + anode region 3;

an anode side electrode 6 and a cathode side electrode 7 are respectively positioned on the front surface and the back surface of the substrate 1;

the P + anode region 3 is located between the anode side electrode 6 and the front side of the substrate 1, and the N + cathode region 2 is located between the cathode side electrode 7 and the back side of the substrate 1.

The P + anode region 3 is located on the front side of the substrate 1 and near the anode side electrode 6, and the N + cathode region 2 is located on the back side of the substrate 1 and near the cathode side electrode 7.

The lifetime control doping layer 4 is formed by ion implantation, and the ion implantation times adopt a single step or multiple steps; the ion implantation mode adopts a light ion implantation mode or a heavy ion implantation mode.

The lifetime control doping layer 4 can regulate the lifetime range of the carriers including the lifetime of the intrinsic carriers and lower, and can regulate the concentration range of the doping layer including the concentration of the P + anode region 3 and lower.

The concentration of the N + cathode region 2 and the concentration of the P + anode region 3 are both higher than that of the substrate 1, and the concentration of the P + doped layer 5 is higher than that of the P + anode region 3.

The substrate 1 may be selected from N-type silicon, but is not limited to N-type silicon. Concentration of substrate 1 was 1E11cm^-3～1E15cm^-3The later degree is 100 um-600 um.

The concentration of the N + cathode region 2 is 1E12cm^-3～1E23cm^-3And the depth of the N + cathode region 2 is 20um to 100 um.

Concentration 1E13cm of P + Anode region 3^-3～1E22cm^-3And the depth of the P + anode region 3 is 3um to 50 um.

Concentration 1E15cm of P + doped layer 5^-3～1E30cm^-3And the depth of the P + doped layer 5 is 1um to 2 um.

The anode-side electrode 6 and the cathode-side electrode 7 are made of a metal material or a semiconductor material, but are not limited to these two materials. The metal material may be aluminum or silver, and the semiconductor material may be polysilicon.

The embodiment of the utility model provides an in the fast recovery diode's doping concentration distribution and life-span distribution sketch map are shown in FIG. 4, can effectively improve recovery diode voltage temperature coefficient, can promote recovery diode zero voltage temperature coefficient point, form the recovery diode of positive voltage temperature coefficient under the rated current condition, improve the parallelly connected characteristic of flow equalizing of recovery diode.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and those skilled in the art can still modify or substitute the specific embodiments of the present invention with reference to the above embodiments, and any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are all within the scope of the claims of the present invention pending.

Claims

1. A fast recovery diode is characterized by comprising a substrate, an N + cathode region, a P + anode region, a service life control doped layer, a P + doped layer, an anode side electrode and a cathode side electrode;

the P + doped layer is positioned inside the life control doped layer, and the life control doped layer is positioned inside the P + anode region;

the anode side electrode and the cathode side electrode are respectively positioned on the front surface and the back surface of the substrate;

the P + anode region is positioned on the front surface of the substrate and close to the anode side electrode, and the N + cathode region is positioned on the back surface of the substrate and close to the cathode side electrode.

2. The fast recovery diode of claim 1 wherein the lifetime-controlling doped layer is formed by ion implantation.

3. The fast recovery diode of claim 2, wherein the ion implantation times are in a single step or multiple steps;

4. The fast recovery diode of claim 1 wherein the N + cathode region and the P + anode region are each at a higher concentration than the substrate, and the P + doped layer is at a higher concentration than the P + anode region.

5. The fast recovery diode of claim 4 wherein the concentration of the substrate is 1E11cm^-3～1E15cm^-3The later degree is 100 um-600 um.

6. The fast recovery diode of claim 1 wherein the concentration of the N + cathode region is 1E12cm^-3～1E23cm^-3And the depth of the N + cathode region is 20 um-100 um.

7. The fast recovery diode of claim 1 wherein the concentration of the P + anode region is 1E13cm^-3～1E22cm^-3And the depth of the P + anode region is 3um to 50 um.

8. The fast recovery diode of claim 1 wherein the concentration of the P + doped layer is 1E15cm^-3～1E30cm^-3And the depth of the P + doped layer is 1um to 2 um.