WO2011082633A1

WO2011082633A1 - Semiconductor device with p-n junction

Info

Publication number: WO2011082633A1
Application number: PCT/CN2010/080256
Authority: WO
Inventors: Zhenqiang Zhou; Tanghua Jiang
Original assignee: Byd Company Limited
Priority date: 2010-01-05
Filing date: 2010-12-24
Publication date: 2011-07-14
Also published as: CN102117839B; CN102117839A

Abstract

A semiconductor device with a p-n junction is provided. The semiconductor device may comprise a p-doped region, and an n-doped region adjacent to the p-doped region. A first doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part may first increase and then decrease in a direction from the p-doped region to an interface between the p-doped region and the n-doped region. A second doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part may first decrease and then increase in a direction from the n-doped region to the interface between the p-doped region and the n-doped region.

Description

SEMICONDUCTOR DEVICE WITH P-N JUNCTION

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and benefits of Chinese Patent Application No. 201010042636.4 filed with the State Intellectual Property Office, P. R. C. on January 5^th, 2010, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure generally relates to a semiconductor device, more particularly, to a semiconductor device with a p-n junction.

BACKGROUND

The semiconductor device not only has important static parameters such as withstand voltage, reverse leakage current and on-state voltage drop, but also has important dynamic parameters such as recovery speed, softness and flatness. The recovery speed determines a frequency band width of the semiconductor device in the field to which the semiconductor device is applied. The softness and the flatness determine safety and reliability of the semiconductor device. The stability mainly reflects anti- interference capability of the semiconductor device to random factors such as the inductance and the switching of a circuit. The more sensitive the semiconductor device to the changes of these factors, the worse the flatness of the semiconductor is. For the semiconductor device with good flatness, a recovery wave, i.e. the current wave or the voltage wave, is constant and will not vary obviously with the parameters of the circuit.

Ideally, the semiconductor device may have a smooth current curve. However, the actual current curve thereof may have current peaks caused by switching, inductance etc.. Nowadays, the semiconductor device is optimized only by adjusting the static parameters, the recovery speed and the softness. However, the poor stability caused by the displacement current is ignored. Therefore, in practical applications, few semiconductor devices do not contain current or voltage peaks caused by the displacement current. SUMMARY

The present disclosure is directed to solve at least one of the problems existing in the prior art. Accordingly, a semiconductor device is provided, which may restrain the displacement current and optimize parameters thereof such as flatness etc.

According to an aspect of the present disclosure, a semiconductor device with a p-n junction is provided. The semiconductor device with a p-n junction comprises: a p-doped region comprising a first p-doped part; and an n-doped region adjacent to the p-doped region comprising a first n-doped part, in which a first doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part first increases and then decreases in a direction from the p-doped region to an interface between the p-doped region and the n-doped region, and a second doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part first decreases and then increases in a direction from the n-doped region to the interface between the p-doped region and the n-doped region.

According to another aspect of the present disclosure, a semiconductor device with a p-n junction is provided. The semiconductor device with a p-n junction may comprise: a p-doped region comprising a first p-doped part; and an n-doped region adjacent to the p-doped region comprising a first n-doped part, in which a fifth doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part first decreases and then increases in a direction from the p-doped region to the interface between the p-doped region and the n-doped region, and a sixth doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part first increases and then decreases in a direction form the n-doped region to the interface between the p-doped region and the n-doped region.

According to the above embodiments of the present disclosure, the displacement current may be restrained by changing the doping concentration distribution of the p-type and n-type impurities or the lifetime distribution of the minority carrier, the first doping concentration distribution of the p-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first p-doped part first increases and then decreases in the direction from the p-doped region n to the interface between the p-doped region and the n-doped regio, and the second doping concentration distribution of the n-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first n-doped part first decreases and then increases in the direction from the n-doped region to the interface between the p-doped region and the n-doped region, so the displacement current is restrained when the semiconductor device is in a forward recovery process; and the fifth doping concentration distribution of the p-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first p-doped part first decreases and then increases in the direction from the p-doped region to the interface between the p-doped region and the n-doped region, and the sixth doping concentration distribution of the n-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first n-doped part first increases and then decreases in the direction from the n-doped region to the interface between the p-doped region and the n-doped region, so the displacement current is restrained when the semiconductor device is in a reverse recovery process. Moreover, with the present disclosure, the displacement current is restrained when the semiconductor device is in the forward or reverse recovery process. Therefore, the purposes of partly or completely restraining the displacement current may be achieved, thus optimizing parameters of the semiconductor such as flatness etc.

Additional aspects and advantages of the embodiments of the present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the disclosure will become apparent and more readily appreciated from the following descriptions taken in conjunction with the drawings in which:

d

Fig. 1A is a curve diagram of the — (P ^{_ n}) in a forward recovery process in the

<5t

prior art; Fig. IB is a schematic diagram showing a flowing direction of the displacement current density in a forward recovery process in the prior art;

d

Fig. 2 A is a curve diagram of the — (P ^{_ n}) in a reverse recovery process in the

<5t

prior art;

Fig. 2B is a schematic diagram showing a flowing direction of a displacement current density in a reverse recovery process in the prior art;

Fig. 3A is a curve diagram showing a displacement current density in a forward recovery process in the prior art;

Fig. 3B is a curve diagram showing a doping concentration distribution or an opposite number of the lifetime distribution of minority carriers in a p-doped region in a forward recovery process according to an embodiment of the present disclosure;

Fig. 3C is a curve diagram showing a doping concentration distribution or an opposite number of the lifetime distribution of minority carriers in an n-doped region in a forward recovery process according to an embodiment of the present disclosure;

Fig. 3D is a curve diagram showing a doping concentration distribution or an opposite number of the lifetime distribution of minority carriers in a p-doped region and a doping concentration distribution or an opposite number of a lifetime distribution of minority carriers in the n-doped region in a forward recovery process according to an embodiment of the present disclosure;

Fig. 4A is a curve diagram showing a displacement current density in a reverse recovery process according to an embodiment of the present disclosure;

Fig. 4B is a curve diagram showing a doping concentration distribution or an opposite number of the lifetime distribution of minority carriers in a p-doped region in a reverse recovery process according to an embodiment of the present disclosure;

Fig. 4C is a curve diagram showing a doping concentration distribution or an opposite number of a lifetime distribution of minority carriers in an n-doped region in a reverse recovery process according to an embodiment of the present disclosure;

Fig. 4D is a curve diagram showing a doping concentration distribution or an opposite number of a lifetime distribution of minority carriers in a p-doped region and a doping concentration distribution or an opposite number of a lifetime distribution of minority carriers in an n-doped region in a reverse recovery process according to an embodiment of the present disclosure;

Fig. 5A is a curve diagram showing a doping concentration distribution or an opposite number of a lifetime distribution of minority carriers in a semiconductor with a p-n junction according to an embodiment of the present disclosure; and

Fig. 5B is a doping schematic diagram showing a doping concentration distribution or an opposite number of a lifetime distribution of minority carriers in the p-n junction according to an embodiment of the present disclosure. DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to the accompany drawings are explanatory and illustrative, which are used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure.

In some embodiments of the present disclosure, a semiconductor device with a p-n junction comprises a p-doped region and an n-doped region. The n-doped region comprises a heavy n-doped region, i.e., N+ region, and a light n-doped region, i.e., N- region. To restrain a displacement current in the semiconductor device, a doping concentration distribution or an opposite number of the lifetime distribution of minority carriers is varied according to a direction of the displacement current density in the semiconductor device in a forward recovery process and a reverse recovery process, a relationship between the doping concentration of a p-type impurity and the effective value of the doping concentration of the p-type impurity, and a relationship between the doping concentration of an n-type impurity and the effective value of the doping concentration of the n-type impurity.

Conductive current will not destroy the whole electric neutrality in the conductive region, so the conductive current will not become an effective charge to affect the effective value of the doping concentration of the impurities. Under the same electric field, the injection speed of the hole is less than that of the electron, and the leaving speed of the hole is less than that of the electron (the mobility of the hole is less than that of the electron in the silicon), which make the effective value of the doping concentration of the n-type impurity Ndeff less than the value of the doping concentration of the n-type impurity Nd in the forward recovery process and the effective value of the doping concentration of the n-type impurity Ndeff greater than the value of the doping concentration of the n-type impurity Nd in the reverse recovery process.

In a conventional semiconductor device, the value of the doping concentration of the n-type impurity Nd is constant or changes monotonously because of the diffusion, so the effective value of the doping concentration of the n-type impurity Ndeff changes in a wider range and the width of the depletion layer changes in a wider range compared with the value of the doping concentration of the n-type impurity Nd, which causes a trend of oscillation of the current or the voltage in the anode and the cathode in the forward or reverse recovery process. Moreover, the value of the doping concentration of the p-type impurity N_a and the effective value of the doping concentration of the p-type impurity N_aeff also have the same or similar problems. The fluctuation direction of the effective value of the doping concentration of the p-type impurity N_aeff is contrary to that of the effective value of the doping concentration of the n-type impurity Ndeff.

In the p-n junction of the semiconductor device, the displacement current density Jd, the effective value of the doping concentration of the n-type impurity Ndeff and the effective value of the doping concentration of the p-type impurity N_aeff are calculated as follows.

Using a point in the interface between the n-doped region and the P-doped region as the origin and the direction from the p-doped region to the n-doped region as an x-axis, the x-axis coordinate of the anode is -a, and the x-axis coordinate of the cathode is c, so that formulas as follows are established as such:

J_d (c) _* 0

J d

d ( x) =— [ε Ε ( ^χ)]

at JH ( ^Χ) - JH ( 0) = q— 1 ( p - n)dx

E ( x) - E (0) ( p - n + N . ) dx J_d (c) - J_d (0) = q— P ( p - n)dx => J_d (0) = - q— P ( p - n) dx

fit 0 fit 0

J_H ( x) J_H (0) 5 c ( p - n) and N_deff( x) = N_d => N^O) = N_d = _d— dx

a qvv_s a qvv_s a 3tt u U v v_s where J_d is the displacement current density, ε is the dielectric constant, E is an intensity of an electric field, q is an electrical quantity, p is a hole concentration, n is an electron concentration, N_d is a value of the doping concentration of the n-type impurity, N_deff is an effective value of a doping concentration of the n-type impurity, and v_s is a directional migration speed of the carrier.

Similarly,

E (

·^'·

and

and when x ( p - n) dx

where N_a is a value of a doping concentration of the p-type impurity, and N_aeff is an effective value of a doping concentration of the p-type impurity.

After deduction according to the above formulas, the following formulas are obtained:

J - n) dx

When the forward recovery process starts, the diffusing speed of the hole in an anode is less than an extracted speed of the hole in a cathode, the diffusing speed of the electron in the cathode is less than an extracted speed of the electron in the anode, and the mobility of the hole is less than that of the electron in the silicon, so the value of n is reduced d

relative to the value of p, that is —_t ( p - n) > 0 , which makes the direction of the displacement current density J_d point from the anode or the cathode to the interface between the n-doped region and the p-doped region. Because the electron vacancy caused by depletion in the anode is filled rapidly, as the width of the depletion layer becomes narrower, the hole may reach the cathode from the anode more easily. Further, because the mobility of the hole is less than that of the electron in the silicon, in the cathode region, the quantity of the electron increases and the quantity of the hole changes slowly, which may result in net decrease of the positive charge, that is ^N deff ^{< N}d . In the anode region, although the excess hole is being injected, the quantity of the hole changes slowly because of supplement to the cathode region; and because the mobility of the hole is less than that of the electron in the silicon, so the collecting speed of the electron is larger than the changing speed of the hole, which may result in net increase of the negative charge, that is N aeff ^{> N} a . Fig. 1A shows a curve diagram of the ^~~Q (P ^{~ n}) in the forward recovery process, and Fig. IB shows a schematic diagram of the flowing direction of the displacement current density in the forward recovery process, in which the increment of the electron corresponds to the decrease of the value of the doping concentration of the n-type impurity Nd.

When the reverse recovery process starts, the diffusing speed of the electron in the anode is greater than the extracted speed of the hole in the cathode, the diffusing speed of the hole in the cathode is less than the extracted speed of the electron in the anode, and the mobility of the hole is less than that of the electron in the silicon, so the value of n is d

increased relative to the value of p, that is —_χ ( p - n) < 0 , which makes the direction of the displacement current density Jd point from the interface between the n-doped region and the p-doped region to the anode or the cathode. Because almost all of the excess electron in the anode is driven by the electric field, as the width of the depletion layer becomes larger, the hole may reach the anode from the cathode more easily; and because the mobility of the hole is less than that of the electron in the silicon, in the cathode region, the quantity of the electron decreases sharply and the quantity of the hole changes slowly, which may result in net increase of the positive charge, that is ^N deff ^{> N}d . In the anode region, although the excess hole is collected, the quantity of the hole changes slowly because of supplementation of the holes to the cathode region; and because the mobility of the hole is less than that of the electron in the silicon, the driven speed of the electron is larger than the changing speed of the hole, which may result in net decrease of the d

negative charge, that is ^N aeff ^{> N} a . Fig. 2 A is a curve diagram of the — (P ^{_ n}) in

<5t the reverse recovery process; and Fig. 2B is a schematic diagram of the flowing direction of the displacement current density in the reverse recovery process, in which the increment of the hole corresponds to the increment of the value of the doping concentration of the n-type impurity N_d.

As can be concluded from the analysis mentioned above, for the doping concentration distribution of the effective value of the impurity in the p-doped region and the N- region in the forward recovery process and the reverse recovery process, the displacement current may be restrained by changing the doping concentration distribution of the impurity or the lifetime of the minority carrier in the p-doped region and the N- region. The terminology "lifetime of the minority carrier" may mean an average time interval from the time when the minority carrier is generated to the time when the minority carrier is combined. In some embodiments of the present disclosure, the lifetime distribution of the minority carrier may be changed by:

(1) doping a heavy metal such as platinum;

(2) using an electron irradiating, which may comprise the steps of: putting the semiconductor device in an irradiation field; and bombarding the semiconductor device by using high energy electron to make the silicon atom in the semiconductor device break away from the normal lattice position, so as to form oxygen vacancy, phosphorus vacancy, bivacancy and so on to form a variety of deep level recombination centers in the silicon forbidden band, in which the electron irradiating may have the characteristic that the life of the minority carrier is controlled by adjusting the injection quantity of the electron; and

(3) using the light ion injection such as the helion injection and the neutron irradiation, in which the principle of the light ion injection is similar to that of the electron irradiation, but the volume of the light ion is larger than that of the electron, so the depth, that the light ion with certain energy may penetrate through in the silicon, may be confirmed and consequently the life time of the minority carrier may be controlled by adjusting the injection quantity of the light ion. In some embodiments of the present disclosure, the light ion injection technology is used to change the lifetime distribution of the minority carrier.

In some embodiments of the present disclosure, the p-n junction comprises a p-doped region comprising a first p-doped part and an n-doped region adjacent to the p-doped region comprising a first n-doped part. As shown in Fig. 3A to Fig. 3D, in the forward recovery process, to restrain the first increasing and then decreasing of the displacement current density J_d shown in Fig. 3A, a first doping concentration distribution of a p-type impurity N_a or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part is first increased and then decreased as shown in Fig. 3B, and a second doping concentration distribution of an n-type impurity N_d or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part is first decreased and then increased as shown in Fig. 3C. Fig. 3D is a curve diagram of the doping concentration distribution or the opposite number of the lifetime distribution of the minority carrier in the p-doped region and the doping concentration distribution or the opposite number of the lifetime distribution of the minority carrier in the n-doped region in the forward recovery process according to an embodiment of the present disclosure. In Fig. 3D, the first n-doped part is a light n-doped region, i.e., N- region. As shown in Fig. 3D, a first doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part first increases and then decreases in a direction from the p-doped region to an interface between the p-doped region and the n-doped region, and a second doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part first decreases and then increases in a direction from the n-doped region to the interface between the p-doped region and the n-doped region.

In some embodiments of the present disclosure, the p-doped region further comprises a second p-doped part and the n-doped region further comprises a second n-doped part. In the reverse recovery process, to restrain the first increasing and then decreasing of the displacement current density J_d, a third doping concentration distribution of a p-type impurity N_a or an opposite number of a lifetime distribution of a minority carrier in the second p-doped part is first decreased and then increased, and a fourth doping concentration distribution of an n-type impurity N_d or an opposite number of a lifetime distribution of a minority carrier in the second n-doped part is first increased and then decreased.

In some embodiments of the present disclosure, the p-n junction comprises a p-doped region comprising a first p-doped part and an n-doped region adjacent to the p-doped region comprising a first n-doped part. As shown in Fig. 4A to Fig. 4D, in the reverse recovery process, to restrain the first increasing and then decreasing of the displacement current density J_d shown in Fig. 4A, a fifth doping concentration distribution of a p-type impurity N_a or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part is first decreased and then increased as shown in Fig. 4B, and a sixth doping concentration distribution of an n-type impurity N_d or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part is first increased and then decreased as shown in Fig. 4C. Fig. 4D is a curve diagram of the doping concentration distribution or the opposite number of the lifetime distribution of the minority carrier in the p-doped region and the doping concentration distribution or the opposite number of the lifetime distribution of the minority carrier in the n-doped region in the reverse recovery process according to an embodiment of the present disclosure. In Fig. 4D, the first n-doped part is a light n-doped region N- region. As shown in Fig. 4D, a fifth doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part first decreases and then increases in a direction from the p-doped region to the interface between the p-doped region and the n-doped region, and a sixth doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part first increases and then decreases in a direction form the n-doped region to the interface between the p-doped region and the n-doped region.

The above methods for changing the doping concentration distribution of the impurity or the lifetime of the minority carrier in the p-doped region and the N- region may be carried out independently, to restraining the displacement current in the forward recovery process or the reverse recovery process. Moreover, the above methods for changing the doping concentration distribution of the impurity or the lifetime of the minority carrier in the p-doped region and the N- region may be carried out simultaneously, to restraining the displacement current in the forward recovery process and the reverse recovery process.

In some embodiments of the present disclosure, in the forward or reverse recovery process, to obtain a steady displacement current density J_d, the p-doped region is divided into a plurality of p-doped parts and the n-doped region is divided into a plurality of n-doped parts. In the first p-doped part or some p-doped parts of the p-doped region, the doping concentration distribution of a p-type impurity or the opposite number of the lifetime distribution of the minority carrier first increases and then decreases in the direction from the p-doped region to the interface between the p-doped region and the n-doped region. In the second p-doped part or some p-doped parts of the p-doped region, the doping concentration distribution of the p-type impurity or the opposite number of the lifetime distribution of the minority carrier first decreases and then increases in the direction from the p-doped region to the interface between the p-doped region and the n-doped region. In the first n-doped part or some n-doped parts of the n-doped region, the doping concentration distribution of the n-type impurity or the opposite number of the lifetime distribution of the minority carrier first decreases and then increases in the direction from the n-doped region to the interface between the p-doped region and the n-doped region. In the second n-doped part or some n-doped parts of the n-doped region, the doping concentration distribution of the n-type impurity or the opposite number of the lifetime distribution of the minority carrier first increases and then decreases in the direction from the n-doped region to the interface between the p-doped region and the n-doped region.

Fig. 5A shows a curve diagram of the doping concentration distribution and the opposite number of the lifetime distribution of the minority carrier in the p-n junction of the semiconductor device. Fig. 5A shows the doping concentration distribution and the opposite number of the lifetime distribution of the minority carrier in a profile perpendicular to the interface between the p-doped region and the n-doped region in the p-n junction. In the profile, the doping concentration of the p-type impurity comprises a wave change in the p-doped region, and the doping concentration of the n-type impurity comprises a wave change in the n-doped region. The distribution may be achieved through a doping technology.

Fig. 5B is a doping schematic diagram of the doping concentration distribution and the opposite number of the lifetime distribution of the minority carrier in the p-n junction of the semiconductor device. In some embodiments of the present disclosure, the p-doped region is divided into a plurality of p-doped parts and the n-doped region is divided into a plurality of n-doped parts. The first p-doped part or each of some p-doped parts is divided into a first p-doped sub-part adjacent to the interface between the p-doped region and the n-doped region and a second p-doped sub-part adjacent to the first p-doped sub-part, and the first n-doped part or each of the n-doped parts is divided into a first n-doped sub-part adjacent to the interface between the p-doped region and the n-doped region and a second n-doped sub-part adjacent to the first n-doped sub-part. The impurity concentration in the second p-doped sub-part is less than that in the first p-doped sub-part, the second p-doped sub-part is two times the thickness of the first p-doped sub-part, the impurity concentration in the second n-doped sub-part is larger than that in the first n-doped sub-part, and the second n-doped sub-part is two times the thickness of the first n-doped sub-part.

In some embodiments of the present disclosure, the p-doped region is divided into a plurality of p-doped parts and the n-doped region is divided into a plurality of n-doped parts. A first p-doped part or each of some p-doped parts is divided into a third p-doped sub-part adjacent to the interface between the p-doped region and the n-doped region and a fourth p-doped sub-part adjacent to the third p-doped sub-part, and a first n-doped part or each of some n-doped parts is divided into a third n-doped sub-part adjacent to the interface between the p-doped region and the n-doped region and a fourth n-doped sub-part adjacent to the third n-doped sub-part. The impurity concentration in the fourth p-doped sub-part is larger than that in the third p-doped sub-part, the fourth p-doped sub-part is two times the thickness of the third p-doped sub-part, the impurity concentration in the fourth n-doped sub-part is less than that in the third n-doped sub-part, and the fourth n-doped sub-part is two times the thickness of the third n-doped sub-part.

In some embodiments, the semiconductor device may be a switching diode, a rectifier diode, an insulated gate bipolar transistor (IGBT), a thyristor, a triode or a fast recovery diode (FRD) etc.

According to the above embodiments of the present disclosure, the displacement current may be restrained by changing the doping concentration distribution of the p-type and n-type impurities and the lifetime distribution of the minority carrier, the first doping concentration distribution of the p-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first p-doped part first increases and then decreases in the direction from the p-doped region to the interface between the p-doped region and the n-doped region, and the second doping concentration distribution of the n-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first n-doped part first decreases and then increases in the direction from the n-doped region to the interface between the p-doped region and the n-doped region, so the displacement current is restrained when the semiconductor device is in a forward recovery process; and the fifth doping concentration distribution of the p-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first p-doped part first decreases and then increases in the direction from the p-doped region to the interface between the p-doped region and the n-doped region, and the sixth doping concentration distribution of the n-type impurity or the opposite number of the lifetime distribution of the minority carrier in the first n-doped part first increases and then decreases in the direction from the n-doped region to the interface between the p-doped region and the n-doped region, so the displacement current is restrained when the semiconductor device is in a reverse recovery process. Moreover, by using the above methods, the displacement current is restrained when the semiconductor device is in forward and reverse recovery processes. Therefore, the purposes of partly or completely restraining the displacement current may be achieved, thus optimizing the parameters of the semiconductor such as flatness etc.

It will be appreciated by those skilled in the art that changes could be made to the examples described above without departing from the broad inventive concept. It is understood, therefore, that this disclosure is not limited to the particular examples disclosed, but it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the appended claims.

Claims

What is claimed is:

1. A semiconductor device with a p-n junction, comprising:

a p-doped region comprising a first p-doped part; and

an n-doped region adjacent to the p-doped region comprising a first n-doped part, wherein a first doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part first increases and then decreases in a direction from the p-doped region to an interface between the p-doped region and the n-doped region, and a second doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part first decreases and then increases in a direction from the n-doped region to the interface between the p-doped region and the n-doped region.

2. The semiconductor device of claim 1, wherein the semiconductor device is a switching diode, a rectifier diode, an insulated gate bipolar transistor, a thyristor, a triode or a fast recovery diode.

3. The semiconductor device of claim 1, wherein

the p-doped region further comprises a second p-doped part, in which a third doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the second p-doped part first decreases and then increases in a direction from the p-doped region to the interface between the p-doped region and the n-doped region; and

the n-doped region further comprises a second n-doped part, in which a fourth doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier first increases and then decreases in a direction from the n-doped region to the interface between the p-doped region and the n-doped region.

4. The semiconductor device of claim 3, wherein the semiconductor device is a switching diode, a rectifier diode, an insulated gate bipolar transistor, a thyristor, a triode or a fast recovery diode.

5. The semiconductor device of claim 3, wherein

the first p-doped part comprises:

a first p-doped sub-part adjacent to the interface between the p-doped region and the n-doped region; and

a second p-doped sub-part adjacent to the first p-doped sub-part, and

the first n-doped part comprises:

a first n-doped sub-part adjacent to the interface between the p-doped region and the n-doped region; and

a second n-doped sub-part adjacent to the first n-doped sub-part,

wherein the impurity concentration in the second p-doped sub-part is less than that in the first p-doped sub-part, and the second p-doped sub-part has a thickness that is two times of that of the first p-doped sub-part, and

the impurity concentration in the second n-doped sub-part is larger than that in the second n-doped sub-part, and the second n-doped sub-part has a thickness that is two times of that of the first n-doped sub-part.

6. The semiconductor device of claim 3, wherein

the first p-doped part comprises:

a third p-doped sub-part adjacent to the interface between the p-doped region and the n-doped region; and

a fourth p-doped sub-part adjacent to the third p-doped sub-part; and

the first n-doped part comprises:

a third n-doped sub-part adjacent to the interface between the p-doped region and the n-doped region; and

a fourth n-doped sub-part adjacent to the third n-doped sub-part,

wherein the impurity concentration in the fourth p-doped sub-part is larger than that in the third p-doped sub-part, and the fourth p-doped sub-part has a thickness that is two times of that of the third p-doped sub-part, and

the impurity concentration in the third n-doped sub-part is less than that in the fourth n-doped sub-part, and the third n-doped sub-part has a thickness that is two times of that of the fourth n-doped sub-part.

7. A semiconductor device with a p-n junction, comprising:

a p-doped region comprising a first p-doped part; and

an n-doped region adjacent to the p-doped region comprising a first n-doped part, wherein a fifth doping concentration distribution of a p-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first p-doped part first decreases and then increases in a direction from the p-doped region to the interface between the p-doped region and the n-doped region, and

a sixth doping concentration distribution of an n-type impurity or an opposite number of a lifetime distribution of a minority carrier in the first n-doped part first increases and then decreases in a direction form the interface between the n-doped region to the p-doped region and the n-doped region.

8. The semiconductor device of claim 7, wherein the semiconductor device is a switching diode, a rectifier diode, an insulated gate bipolar transistor, a thyristor, a triode or a fast recovery diode.

9. The semiconductor device of claim 7, wherein

the first p-doped part comprises:

a second p-doped sub-part adjacent to the first p-doped sub-part, and

the first n-doped part comprises:

a second n-doped sub-part adjacent to the first n-doped sub-part,

wherein the impurity concentration in the second p-doped sub-part is larger than that in the first p-doped sub-part, and the second p-doped sub-part has a thickness that is two times of that of the first p-doped sub-part, and

the impurity concentration in the first n-doped sub-part is less than that in the second n-doped sub-part, and the first n-doped sub-part has a thickness that is two times of that of the second n-doped sub-part.