CN106803498A - A kind of inverse preparation method for leading IGBT device - Google Patents

Abstract

The invention discloses a preparation method of a reverse conduction IGBT device, comprising: step 1, setting a barrier layer on the front IGBT region of the partitioned reverse conduction IGBT device main body; step 2, setting the FRD on the reverse conduction IGBT device main body Perform ion implantation or diffusion on the front side of the region to form a minority carrier lifetime control layer in the FRD region; step 3, remove the barrier layer on the front side of the reverse conduction IGBT device body; An epitaxial layer is formed, and the material of the epitaxial layer is the same as that of the body region of the main body of the reverse conduction IGBT device. In the preparation method of the reverse conduction IGBT device, a barrier layer is set in the IGBT region first, and then ion implantation is performed on the FRD region to control the minority carrier lifetime of the FRD region. With the same epitaxial layer, the minority carrier control layer formed by ion implantation or diffusion in the FRD region is in the body region, while the minority carrier lifetime of the IGBT region is not affected, and the process is simple and the manufacturing cost is low.

Description

A kind of preparation method of reverse conduction IGBT device

technical field

The invention relates to the technical field of semiconductor device preparation, in particular to a preparation method of a reverse conduction IGBT device.

Background technique

Since the traditional IGBT (Insulate Gate Bipolar Transistor, Insulated Gate Bipolar Transistor) has a buffer layer on the back and has no reverse voltage withstand capability, a diode needs to be connected in parallel to withstand the reverse voltage during application, which increases packaging, welding The problem also increases the cost of the IGBT module.

In response to this problem, someone proposed RC-IGBT (reverse-conducting insulated-gate bipolar transistor, reverse conducting insulated gate bipolar transistor), which is realized by forming a spaced P-type collector and N-type collector on the back. In the integration of IGBT and diode, the collector is composed of P-type collector area and N-type collector area, and the P-type collector area and N-type collector area are evenly spaced at the bottom of the active area of the device. In this way, during reverse conduction, the P-type base region of the IGBT acts as the anode of the diode, and the N-type collector acts as the cathode of the diode, realizing the integration of the diode. However, during the forward conduction, the introduction of the N-type collector region will make The current-voltage output curve of this traditional RC-IGBT has a negative resistance effect.

In view of the negative resistance effect, some scholars have proposed to change the distribution of the IGBT region and the diode region on the basis of the traditional RC-IGBT device structure, so that the IGBT part and the diode part of the device are separated. With such a design structure, when the RC-IGBT works in the IGBT mode, the IGBT area is not affected by the diode, and when the RC-IGBT works in the diode mode, the properties of the diode will not be affected by the IGBT, and the forward conduction is realized. At that time, the independent working ability of the IGBT suppressed the phenomenon very well.

This new RC-IGBT has the advantages of high current density and simple packaging due to the integration of IGBT and FRD. Electron irradiation or Pt/He/H injection is used to control the minority carrier lifetime, but as an IGBT, it is not desirable that the minority carrier lifetime is too low to cause a large turn-on voltage drop. This causes a great contradiction, that is, the new type of RC-IGBT obtained by increasing the manufacturing cost requires a compromise between the functional characteristics of the IGBT and the FRD.

Contents of the invention

The purpose of the present invention is to provide a preparation method of a reverse conduction IGBT device, which eliminates the negative resistance effect, and at the same time can control the minority carrier lifetime of the diode part without affecting the carrier lifetime of the IGBT part.

In order to solve the above-mentioned technical problems, the embodiment of the present invention provides a preparation method of a reverse conduction IGBT device, comprising:

Step 1, setting a barrier layer on the front IGBT region of the partitioned reverse conduction IGBT device body;

Step 2, performing ion implantation or diffusion on the front side of the FRD region of the reverse conduction IGBT device body, forming a minority carrier lifetime control layer in the FRD region;

Step 3, removing the barrier layer on the front side of the reverse conduction IGBT device body;

Step 4, forming an epitaxial layer on the front surface of the main body of the reverse conducting IGBT device, the material of the epitaxial layer is the same as that of the bulk region of the main body of the reverse conducting IGBT device.

Wherein, the barrier layer is a photoresist layer or a dielectric layer.

Wherein, the barrier layer is a silicon dioxide dielectric layer or a silicon nitride dielectric layer.

Wherein, performing ion implantation on the front side of the FRD region of the main body of the reverse conducting IGBT device, and forming a minority carrier lifetime control layer in the FRD region includes:

Using Pt, He or H ion implantation to control the front side of the FRD region to form the minority carrier lifetime control layer, or using Pt or Au to diffuse the front side of the FRD region to form the minority carrier lifetime control layer.

Wherein, after said step 4, it also includes:

Step 5, thinning the back of the reverse conducting IGBT device body to a predetermined thickness, forming a P-type region on the back of the IGBT region, and forming an N-type region on the back of the FRD region;

Step 6, depositing an ohmic contact layer on the back of the P-type region and the N-type region to form an ohmic contact with the P-type region and the N-type region;

Step 7, depositing a metal contact layer on the ohmic contact layer.

Wherein, said depositing an ohmic contact layer on the back side of said P-type region and said N-type region includes:

An aluminum layer of 0.1 μm to 2 μm is deposited on the back of the P-type region and the N-type region as an ohmic contact layer, and the aluminum alloy is annealed.

Wherein, said depositing a metal contact layer on said ohmic contact layer includes:

A titanium metal layer, a nickel metal layer and a silver metal layer are sequentially deposited on the ohmic contact layer.

Compared with the prior art, the preparation method of the reverse conduction IGBT device provided by the embodiment of the present invention has the following advantages:

The preparation method of the reverse conduction IGBT device provided by the embodiment of the present invention comprises:

Step 1, setting a barrier layer on the front IGBT region of the partitioned reverse conduction IGBT device body;

Step 2, performing ion implantation or diffusion on the front side of the FRD region of the reverse conduction IGBT device body, forming a minority carrier lifetime control layer in the FRD region;

Step 3, removing the barrier layer on the front side of the reverse conduction IGBT device body;

Step 4, forming an epitaxial layer on the front surface of the main body of the reverse conducting IGBT device, the material of the epitaxial layer is the same as that of the bulk region of the main body of the reverse conducting IGBT device.

In the preparation method of the reverse conduction IGBT device, a barrier layer is firstly set in the IGBT region, and then ion implantation is performed on the FRD region to control the minority carrier life of the FRD region. The same epitaxial layer shields the minority carrier control layer formed by ion implantation in the FRD region to the body region, so that the minority carrier lifetime of the IGBT region is not affected, and the process is simple and the manufacturing cost is low.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are For some embodiments of the present invention, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic flow chart of the steps of a specific embodiment of a method for preparing a reverse conducting IGBT device provided by an embodiment of the present invention;

FIG. 2 is a schematic flowchart of steps in another specific implementation of the method for manufacturing a reverse-conducting IGBT device provided in an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to Figures 1 to 2, Figure 1 is a schematic flow chart of the steps of a specific implementation of the method for preparing a reverse-conducting IGBT device provided by an embodiment of the present invention; Figure 2 is a schematic diagram of the preparation of a reverse-conducting IGBT device provided by an embodiment of the present invention A schematic flow chart of the steps of another embodiment of the method.

In a specific embodiment, the preparation method of the reverse conduction IGBT device includes:

Step 1. Set a barrier layer on the front IGBT area of the main body of the partitioned reverse-conducting IGBT device; generally use a photolithography plate to partition the surface of semiconductor materials such as silicon wafers, and form IGBT and FRD areas respectively through different processes , thus forming a reverse conduction IGBT. Through the setting of the barrier layer, the subsequent ion implantation into the FRD region of the main body of the reverse conducting IGBT device will not affect the minority carrier lifetime of the IGBT region due to the function of the barrier layer during the formation of the minority carrier lifetime control layer in the FRD region. The present invention does not limit the type, formation method and thickness of the barrier layer.

Step 2, performing ion implantation or diffusion on the front side of the FRD region of the main body of the reverse conducting IGBT device, forming a minority carrier lifetime control layer in the FRD region; by forming the minority carrier control layer, the performance of the FED region is improved.

Step 3, removing the barrier layer on the front side of the reverse conduction IGBT device body; since the barrier layer is not required for the reverse conduction IGBT device body, it needs to be removed after the minority carrier control layer is formed, and the present invention does not remove the barrier layer limited.

Step 4, forming an epitaxial layer on the front side of the main body of the reverse conducting IGBT device, the material of the epitaxial layer is the same as the material of the body region of the main body of the reverse conducting IGBT device, and through the same material as the body region of the main body of the reverse conducting IGBT device The same epitaxial layer covers the minority carrier control layer in the body region, while the minority carrier lifetime of the IGBT region is not affected, and the process is simple and the manufacturing cost is low.

In the preparation method of the reverse conduction IGBT device in the present invention, the IGBT region of the reverse conduction IGBT device body after partitioning is provided with a barrier layer, so that the subsequent FRD region of the reverse conduction IGBT device body is ion-implanted in the FRD region. In the process of the minority carrier lifetime control layer, due to the function of the barrier layer, it will not affect the minority carrier lifetime of the IGBT region, and finally cover a layer of the same epitaxial layer as the body region, which is equivalent to the minority carrier lifetime control layer of the FRD region Buried in the body region of the device, the final reverse-conducting IGBT device can meet the characteristic requirements of IGBT and FRD at the same time, and the minority carrier lifetime of IGBT is not reduced, no need to compromise between IGBT and FRD, and the added process is simple , manufactured to be low.

In the present invention, the barrier layer generally uses a photoresist layer or a dielectric layer to shield the area below the barrier layer.

Among them, photoresist, also known as photoresist, is a photosensitive material used in many industrial processes. In photolithography, a patterned coating can be engraved on the surface of a material.

There are two types of photoresist, positive photoresist and negative photoresist. The positive photoresist is a kind of photoresist, and the part that is exposed to light will dissolve in the photoresist developer, while the part that is not exposed to light will not dissolve in the photoresist developer.

The photoresist here refers to the photoresist, the forward photoresist is the positive photoresist, and the reverse photoresist is the reverse photoresist.

If the blocking layer is a photoresist layer, generally the photoresist layer is a forward photoresist layer.

It should be pointed out that the specific type, arrangement process and thickness of the photoresist layer in the present invention are not specifically limited.

In the present invention, the purpose of setting the blocking layer is to shield the IGBT region, and then perform ion implantation or diffusion on the FRD region, so as to control the minority carrier lifetime of the FRD region without affecting the minority carrier lifetime of the IGBT region.

The thickness of the actual barrier layer in the present invention is related to the barrier capacity per unit thickness of the barrier layer itself, and is also related to the energy of implanted or diffused ions. If the energy of ion or diffusion implantation is very large, the barrier layer will be consumed at this time. More, so the barrier layer should choose a material with stronger barrier ability, and the thickness also needs to be increased accordingly. Therefore, the present invention does not specifically limit the actual thickness of the barrier layer, which needs to be determined in combination with actual use requirements.

In the present invention, the barrier layer can use a photoresist layer, and a dielectric layer can also be used. The dielectric layer is generally a silicon dioxide dielectric layer or a silicon nitride dielectric layer, or other types of silicon nitride dielectric layers. The invention does not specifically limit this.

The ion implantation or diffusion carried out in the present invention is to reduce the lifetime of the minority carrier in the FRD region and introduce recombination centers. Since the minority carriers in the FRD region are generally electrons, the ions used are generally electron recombination centers. Therefore, performing ion implantation or diffusion on the front side of the FRD region of the reverse conduction IGBT device body to form a minority carrier lifetime control layer in the FRD region includes:

Using Pt, He or H ion implantation to control the front side of the FRD region to form the minority carrier lifetime control layer, or using Pt or Au to diffuse the front side of the FRD region to form the minority carrier lifetime control layer.

It should be pointed out that in the present invention, in addition to using Pt, He or H ions, other types of ions can also be used, or mixed implantation of these ions. The present invention does not specifically limit the type and concentration of implanted ions. The energy carried by the ions needs to be changed accordingly depending on the depth of the minority carrier control layer.

The present invention can also use other impurities to diffuse on the front of the FRD region, as long as the doping type (N-type or P-type) is the same as that of Pt and Au, the present invention does not limit the concentration and depth of diffusion .

After the growth of the epitaxial layer is completed, and the minority carrier control center of the FRD region is buried in the body region of the main body of the reverse conduction IGBT device, subsequent fabrication of the reverse conduction IGBT device can be performed.

After said step 4, also include:

Step 5, thinning the back of the reverse conducting IGBT device body to a predetermined thickness, forming a P-type region on the back of the IGBT region, and forming an N-type region on the back of the FRD region;

Step 6, depositing an ohmic contact layer on the back of the P-type region and the N-type region to form an ohmic contact with the P-type region and the N-type region;

Step 7, depositing a metal contact layer on the ohmic contact layer.

Through step 5, the collector of the corresponding IGBT region and the cathode of the FRD region are manufactured. The present invention does not specifically limit the doping type and doping concentration of the P-type region and the N-type region. Generally, the P-type region is doped with boron, N Phosphorus-doped area.

The present invention does not limit the thinned thickness of the main body of the reverse conduction IGBT device, and does not specifically limit the thinned process.

After the collector of the IGBT area and the cathode of the FRD area are fabricated, the metal electrode needs to be fabricated, but directly depositing the metal electrode on the collector of the IGBT area and the cathode of the FRD area will make the ohmic contact resistance very large, and the device will be turned on The voltage is high. For this reason, depositing an ohmic contact layer on the back of the P-type region and the N-type region includes:

An aluminum layer of 0.1 μm to 2 μm is deposited on the back of the P-type region and the N-type region as an ohmic contact layer, and the aluminum alloy is annealed.

It should be pointed out that the material, thickness and deposition process of the ohmic contact layer in the present invention are not specifically limited. In the present invention, in addition to using the aluminum layer as the ohmic contact layer, under some special conditions, it is also possible to Mo, Ta, Ti, W are used. For example, after the ohmic contact is formed, other process steps above 500°C need to be performed. At this time, the Al-Si contact system cannot withstand such a high temperature treatment, and it is difficult to meet the thermal stability requirements.

After finishing the electrode of ohmic contact layer, need to carry out the deposition of metal electrode layer, general metal electrode layer is Ti/Ni/Ag electrode layer, promptly described metal contact layer is deposited on described ohmic contact layer, comprises:

A titanium metal layer, a nickel metal layer and a silver metal layer are sequentially deposited on the ohmic contact layer.

It should be noted that, in the present invention, the metal contact layer is not limited to Ti/Ni/Ag electrode layer, and other metal contact layers can also be used. and thickness are not specifically limited.

To sum up, the method for manufacturing a reverse-conducting IGBT device provided by the embodiment of the present invention sets a barrier layer in the IGBT region of the reverse-conducting IGBT device body after partitioning, so that the subsequent FRD region of the reverse-conducting IGBT device body Ion implantation or diffusion, in the process of forming the minority carrier lifetime control layer in the FRD region, due to the function of the barrier layer, will not affect the minority carrier lifetime of the IGBT region, and finally cover a layer of the same epitaxial layer as the body region, so that It is equivalent to burying the minority carrier lifetime control layer in the FRD region in the body region of the device, and the final reverse conducting IGBT device can meet the characteristics requirements of IGBT and FRD at the same time, and the minority carrier lifetime of IGBT is not reduced, so it is not used in IGBT and FRD A trade-off is made, while the increased process is simple and the manufacturing cost is low.

The preparation method of the reverse conduction IGBT device provided by the present invention has been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (7)

1. a kind of against the preparation method for leading IGBT device, it is characterised in that including:

Step 1, the inverse positive IGBT areas for leading IGBT device main body to subregion set barrier layer；

Step 2, the front to the inverse FRD areas for leading IGBT device main body carries out ion implanting or diffusion, in the FRD areas Form minority carrier life time key-course；

Step 3, removes the inverse positive barrier layer for leading IGBT device main body；

Step 4, an epitaxial layer is formed in the inverse front for leading IGBT device main body, and the material of the epitaxial layer inverse is led with described The body area material of IGBT device main body is identical.

2. as claimed in claim 1 against the preparation method for leading IGBT device, it is characterised in that the barrier layer is photoresist layer or electricity Dielectric layer.

3. as claimed in claim 2 against the preparation method for leading IGBT device, it is characterised in that the barrier layer is that silica is situated between Matter layer or silicon nitride medium layer.

4. the inverse preparation method for leading IGBT device as claimed in claim 1, it is characterised in that described inverse to lead IGBT device to described The front in the FRD areas of main body carries out ion implanting, and minority carrier life time key-course is formed in the FRD areas, including：

The front in the FRD areas is controlled using Pt, He or H ion implanting, the minority carrier life time key-course is formed, or use Pt, Au spread the front in the FRD areas, form the minority carrier life time key-course.

5. as claimed in claim 1 against the preparation method for leading IGBT device, it is characterised in that after the step 4, also wrap Include：

Step 5, to the inverse thinning back side for leading IGBT device main body to predetermined thickness, P is formed at the back side in the IGBT areas Type area, N-type region is formed at the back side in the FRD areas；

Step 6, ohmic contact layer is deposited at the back side of the p type island region, the N-type region, is formed with the p type island region, the N-type region Ohmic contact；

Step 7, metal contact layer is deposited on the ohmic contact layer.

6. as claimed in claim 5 against the preparation method for leading IGBT device, it is characterised in that described in the p type island region, the N The back side deposit ohmic contact layer in type area, including：

0.1 μm~2 μm of aluminium lamination is deposited as ohmic contact layer at the back side of the p type island region, the N-type region, and carries out aluminium conjunction Annealing of gold.

7. as claimed in claim 5 against the preparation method for leading IGBT device, it is characterised in that described on the ohmic contact layer Deposit metal contact layer, including:

Deposit titanium coating, nickel metal layer and silver metal layer successively on the ohmic contact layer.