CN101853849A - Rectifier applied under high-temperature condition - Google Patents

Abstract

A rectifier for use in high temperature conditions, comprising: a conductive semiconductor substrate; a conductive epitaxial layer; a plurality of conductive type doped regions; an edge conductive type doped region surrounding the plurality of conductive type doped regions; at least one peripheral conductively-doped region surrounding the peripheral conductively-doped region; a first metal layer, which covers the multiple conductive doped regions completely and contacts at least a part of the edge conductive doped region; and a second metal layer formed on the back surface of the conductive semiconductor substrate and surrounding the edge conductive doped region. The invention has the characteristics of low forward voltage and low reverse leakage current, so the invention can be suitable for a high-temperature operation environment; in addition, in order to improve the shock resistance of the element, the periphery of the rectifier has a structure capable of reducing the accumulation of electric field, so that the situation of element damage can be greatly improved.

Description

Rectifiers for high temperature applications

technical field

The invention relates to a rectifier used under high temperature conditions, in particular to a rectifier with good impact resistance.

Background technique

With the continuous improvement of semiconductor process technology capabilities, many power components use a large number of components in the form of diodes. For example, PN junction diodes (PN junction) are often used in alternator systems as rectifier diodes. The advantage of the PN junction diode is that the reverse leakage current is low; but its main disadvantage is that the forward bias (forward voltage; VF) is high. Under normal operating conditions, the forward bias voltage is about 1V, so the PN junction diode More energy waste is generated in the application.

In addition, a Schottky diode (Schottky Diode) can be regarded as another choice of diode components; the advantage of a Schottky diode is that its forward bias voltage is much smaller than that of a PN junction diode; however, a Schottky diode will generate Considerable leakage current, therefore, the high reverse leakage of Schottky diodes is a great disadvantage under the operation of high temperature environment.

Contents of the invention

The invention has a reasonable design and effectively improves the above-mentioned defects. It can combine the advantages of the above two diodes to compensate for the problems in the operation of the two. At the same time, it also proposes an improvement on the rectifier to strengthen the diode's impact resistance to reverse surges. .

The main purpose of the present invention is to provide a rectifier used under high temperature conditions and its manufacturing method. The rectifier has the characteristics of low forward voltage and low leakage current, so that it can have higher operating efficiency under high temperature conditions ; Furthermore, the rectifier has a structure that reduces the accumulation of electric field, so that it has good anti-shock characteristics of reverse surge.

In order to achieve the above object, the present invention provides a rectifier applied under high temperature conditions, comprising: a conductive semiconductor substrate; a conductive epitaxial layer located on the conductive semiconductor substrate; a plurality of conductive doped a region formed in the conductivity type epitaxial layer; an edge conductivity type doped region formed in the conductivity type epitaxial layer and surrounding the plurality of conductivity type doped regions; at least one outer edge conductivity type doped region , which is formed in the conduction type epitaxial layer and surrounds the edge conduction type doped region; a first metal layer, which is arranged on the conduction type epitaxial layer, and the first metal layer completely covers the plurality of conductive type doped region, the first metal layer contacts a part of the edge conduction type doped region, and the shape of the first metal layer corresponds to the shape of the edge conduction type doped region; and a relative to the first metal layer The second metal layer is arranged on the back of the conductive semiconductor substrate.

The present invention has the following beneficial effects: the rectifier proposed by the present invention has the characteristics of low forward voltage (VF) and low reverse leakage current at the same time, so it can be applied to high-temperature operating environments; in addition, in order to improve the impact resistance of components , the rectifier has a structure that can reduce electric field accumulation around the rectifier, so it can greatly improve the damage of components.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the drawings are provided for reference and illustration only, and are not intended to limit the present invention.

Description of drawings

Fig. 1 is a top view of the rectifier of the present invention.

FIG. 1A is a cross-sectional view along line A-A' of FIG. 1 .

FIG. 1B is a cross-sectional view along line B-B' of FIG. 1 .

FIG. 1C is a schematic diagram of a second embodiment of the rectifier of the present invention.

FIG. 1D is a schematic diagram of a third embodiment of the rectifier of the present invention.

2 to 2G are flow charts of the fabrication of the rectifier of the present invention.

FIG. 3 is a schematic diagram of a fourth embodiment of the rectifier of the present invention.

FIG. 3A is a schematic diagram of a fifth embodiment of the rectifier of the present invention.

FIG. 4 is a schematic diagram of a sixth embodiment of the rectifier of the present invention.

FIG. 4A is a schematic diagram of a seventh embodiment of the rectifier of the present invention.

The reference numerals in the above-mentioned accompanying drawings are explained as follows:

1 rectifier

10 Conductive semiconductor substrate

10A Central District

10B Marginal zone

10C Outer zone

10D cutting lane

11 Conductive epitaxial layer

12A conductivity type doped region

12B edge conduction type doped region

12B' high-concentration edge-conduction doped region

12B″ low-concentration edge conduction type doped region

12C Outer conductive type doped region

12C' high-concentration peripheral conductivity type doping region

12C″ low-concentration peripheral conductivity type doped region

12 first metal layer

14 isolation layer

15 second metal layer

20 photoresist

R rounded corners

Detailed ways

Please refer to Fig. 1, the present invention provides a kind of rectifier 1 that is applied under high temperature condition, and rectifier 1 has high efficiency under high temperature operating condition and has the effect of high reliability when operating at high reverse voltage, and rectifier 1 comprises a conductive type semiconductor substrate 10, a conductivity type epitaxial layer 11, a plurality of conductivity type doped regions 12A, an edge conductivity type doped region 12B, at least one outer edge conductivity type doped region 12C, a first metal layer 13, and a The second metal layer 15 (please refer to FIG. 1A and FIG. 1B at the same time).

Fig. 1 shows a specific embodiment of the present invention, wherein conduction type semiconductor substrate 10 is an N-type semiconductor substrate, conduction type epitaxial layer 11 is also an N type epitaxial layer, and according to the difference of doping concentration, conduction type semiconductor The substrate 10 is represented by N+, and the conductive epitaxial layer 11 is represented by N. On the other hand, the conductivity type doped region 12A, the edge conductivity type doped region 12B, and the outer edge conductivity type doped region 12C are all P+ doped regions.

Please refer to FIG. 1 again, and in conjunction with FIG. 1A, which is a cross-sectional view of A-A' in FIG. In the conduction type epitaxial layer 11, the plurality of conduction type doped regions 12A are P-type island regions distributed in the conduction type epitaxial layer 11, and the shape of the plurality of conduction type doped regions 12A can be a quadrangle (such as a rectangle ), circular or hexagonal, and the conductivity-type doped region 12A is covered by a first metal layer 13, so the rectifier 1 can pass through the low Schottky barrier formed by the first metal layer 13, so that The rectifier 1 has a characteristic of low forward voltage (VF).

On the other hand, the structure of the conductivity type epitaxial layer 11 and the plurality of conductivity type doped regions 12A can form a leakage characteristic equivalent to the reverse voltage operation of a PN junction diode, that is, the rectifier 1 has a relatively low leakage current, so that The rectifier 1 of the present invention is quite suitable for high temperature operating environment. In short, the rectifier 1 of the present invention is a rectifier with low voltage and low reverse leakage current.

Furthermore, please refer to FIG. 1, FIG. 1B (the cross-sectional view of B-B' in FIG. 1) and FIG. 1C, wherein the conductivity type epitaxial layer 11 further includes an edge conductivity type doped region 12B and at least one outer edge conductivity type doped region 12B. In the region 12C, the edge conduction type doped region 12B surrounds the plurality of conduction type doped regions 12A, that is, the conduction type doped region 12A is disposed inside the edge conduction type doped region 12B, and the first metal layer 13 contacts A part of the edge conduction type doped region 12B, in other words, the outer edge of the first metal layer 13 will extend outwards from the region of the plurality of conduction type doped regions 12A, and surround the plurality of conduction type doped regions 12A. The edge conduction type doped region 12B outside the region 12A is in contact, and the contact area between the first metal layer 13 and the edge conduction type doped region 12B can be adjusted according to the actual process. The first metal layer 13 covers at least a part of the edge conduction type Type doped region 12B, for example, the first metal layer 13 may cover a part or all of the area of edge conduction type doped region 12B, preferably half of the area of edge conduction type doped region 12B. The electrical contact between the first metal layer 13 and the edge conductive type doped region 12B can reduce the electric field accumulated at the edge of the rectifier 1 , so as to prevent the rectifier 1 from being damaged due to excessive electric field.

1B shows that there is only one doped region 12C of the outer conductivity type, and its size can be the minimum line width of the process; while FIG. 1C shows a structure with two doped regions 12C of the outer conductivity type, each of which is of the outer conductivity type The size of the doped region 12C is also the minimum line width of the process; FIG. 1D shows a wider peripheral conductivity type doped region 12C, the size of which is more than twice the minimum line width of the process. In other words, the rectifier proposed by the present invention 1. The quantity and size of the peripheral conductivity type doped region 12C can be adjusted according to the actual situation.

The appearance of the edge conduction type doped region 12B must also be further considered to avoid the problem of electric field accumulation causing damage to the element. In this embodiment, the edge conduction type doped region 12B has a quadrangular shape, and the quadrangular edges are conductive type doped region 12B has a non-right-angled corner (corner), to avoid electric field accumulation in the electric field at a right-angled position, and for the consideration of photomask design, etc., the quadrilateral edge conduction-type doped region 12B in this embodiment has The arc-shaped corner R, but not limited to the above, for example, the edge conduction type doped region 12B can be in the form of a hexagon, and each corner can also be designed to be arc-shaped, which can also avoid the electric field accumulation on the element Influence. In addition, the appearance of the first metal layer 13 best corresponds to the edge conduction type doped region 12B. In other words, the first metal layer 13 can be quadrilateral or hexagonal, and the first metal layer 13 also has an arc shape (or (non-right angle) corner R, that is, viewed from a top view, the edge conductive type doped region 12B and the first metal layer 13 have a circular arc-shaped corner R.

On the other hand, the outer conduction type doped region 12C is formed in the conduction type epitaxial layer 11 and surrounds the edge conduction type doped region 12B, the outer conduction type doped region 12C is not in contact with the first metal layer 13, please refer to 1B, an isolation layer 14 covers the outer conductive type doped region 12C and the edge conductive type doped region 12B not in contact with the first metal layer 13, and the outer shape of the outer conductive type doped region 12C is also corresponding In the edge conduction type doped region 12B, that is, it has arc-shaped (or non-right-angled) corners, the function of the outer edge conduction type doped region 12C is to provide a relatively gentle electric field distribution, which can also be used in the reverse current In the case of operation, the function of protecting the rectifier 1 is provided; moreover, the number of outer conductive doped regions 12C (as shown in Figure 1B and Figure 1C) and the size and width (as shown in Figure 1D) can be adjusted according to the requirements of the application surface , in order to provide a smoother electric field distribution. Based on the above-mentioned structure, the feature of the present invention is to strengthen the impact (Reversesurge) of preventing the reverse surge on the rectifier 1, and the present invention utilizes the first metal layer 13 to contact a part of the edge conduction type doped region 12B, the arc-shaped corner Structural design, and the setting of the outer edge conductive type doped region 12C and other structures, so as to reduce the damage to the edge of the element during reverse operation.

Moreover, the isolation layer 14 on the conductivity type epitaxial layer 11 covers a part of the peripheral conductivity type doped region 12C and the edge conductivity type doped region 12B (please note that the isolation layer 14 is not drawn in FIG. 1 ), The isolation layer 14 mainly prevents the subsequent encapsulation process from conducting the peripheral conductivity-type doped region 12C; and the backside of the conductivity-type semiconductor substrate 10 is formed with a second metal layer 15, and the second metal layer 15 is mainly used as an electrode.

The manufacturing process of the above-mentioned rectifier 1 will be described in detail below, please refer to FIG. 2 to FIG. 2G:

Step (a) provides a conductive semiconductor substrate 10 , please refer to FIG. 2 . In this embodiment, the conductive semiconductor substrate 10 is an N+ type semiconductor substrate, and for convenience of description, the conductive semiconductor substrate 10 is divided into a central area 10A, an edge area 10B, an outer edge area 10C, and a scribe line 10D.

In step (b), a conductive epitaxial layer 11 is formed on the conductive semiconductor substrate 10 , please refer to FIG. 2 . In this embodiment, the conductivity type epitaxial layer 11 is also an N type epitaxial layer.

Step (c) forming a plurality of conductive type doped regions 12A, an edge conductive type doped region 12B and at least one outer conductive type doped region 12C in the conductive type epitaxial layer 11 , please refer to FIG. 2A . Next, using the photoresist 20, the conductivity-type doped region 12A is defined in the central region 10A (only one conductivity-type doped region 12A is drawn in FIG. 2A ), and the edge conductivity-type doped region 12B is defined in the edge region 10B. The outer edge conductivity type doped region 12C is defined in the outer edge region 10C, and in this step, the plurality of P+ type dopant ions can be implanted into the edge conductivity type doped region in the conductivity type epitaxial layer 11 by using techniques such as ion implantation The peripheral conductive type doped region and the peripheral conductive type doped region.

In addition, the outer conductive type doped region 12C is formed in the conductive epitaxial layer 11 and surrounds the edge conductive type doped region 12B, which also has arc-shaped (or non-right-angled) corners. The outer conductive type doped region 12C The function is to provide a relatively gentle electric field distribution, which can also provide the function of protecting the rectifier 1 in the case of reverse current operation; moreover, the number and width of the outer conductive type doped region 12C can be determined according to the application surface The needs are adjusted to provide a smoother electric field distribution.

In step (d), an isolation layer 14 is formed on the conductive epitaxial layer 11 , please refer to FIG. 2C and FIG. 2D . The isolation layer 14 covers a part of the outer conductive type doped region 12C and the edge conductive type doped region 12B. In this step, an oxide layer (that is, the isolation layer 14) is first formed by an oxidation step, and at the same time, the above-mentioned P+ type dopant ions can be pushed to a predetermined depth by using high temperature; then the isolation layer 14 is formed on the conductive epitaxial layer 11 , and cover a part of the peripheral conductivity type doped region 12C and the edge conductivity type doped region 12B.

Step (e) forms a first metal layer 13 , please refer to FIG. 2E and FIG. 2F . In this step, a first metal layer 13 is first formed on the conductive epitaxial layer 11 and the isolation layer 14 by using a metal process. The first metal layer 13 completely covers the conductive type doped region 12A and contacts the edge conductive type The portion of the doped region 12B that is not covered by the isolation layer 14 , and the first metal layer 13 bridges over the isolation layer 14 to avoid exposing the edge conductivity type doped region 12B. In other words, the outer edge of the first metal layer 13 extends out of the conductive doped region 12A to be in contact with the edge conductive doped region 12B surrounding the conductive doped region 12A, and the first metal The contact area between the layer 13 and the edge conduction type doped region 12B can be adjusted according to the actual process, for example, the first metal layer 13 can cover part or all of the area of the edge conduction type doped region 12B, preferably the edge conduction type One-half of the area of the doped region 12B.

Step (e) forming a second metal layer 15 on the back of the conductive semiconductor substrate 10 , please refer to FIG. 2G . In consideration of the thickness of the conductive semiconductor substrate 10 , before the step of forming the second metal layer 15 , a thinning step may be performed to thin the thickness of the conductive semiconductor substrate 10 .

Through the above steps, the above-mentioned rectifier 1 applied under high temperature conditions can be completed. The rectifier 1 is a diode with low voltage and low reverse leakage current, and it has improved surrounding characteristics to strengthen the prevention of reverse surge. For the rectifier 1 shock.

Please refer to FIG. 3 , which is a fourth embodiment of the rectifier 1 of the present invention. The difference between the second embodiment and the first embodiment lies in the characteristics of the edge conduction type doped region 12B and the outer edge conduction type doped region 12C. In this embodiment, the doping ion concentration of the outer conductive type doped region 12C is lower than the doping ion concentration of each conductive type doped region 12A and the edge conductive type doped region 12B, and the outer conductive type doped region The doping ion depth of the region 12C is greater than the doping ion depth of each conductivity type doping region 12A and the edge conductivity type doping region 12B, in other words, the conductivity type doping region 12A and the edge conductivity type doping region 12B are P+ regions , and its doping depth is relatively shallow; and the peripheral conductivity type doped region 12C is a P-region, and its doping depth is relatively deep.

Please refer to FIG. 3A , which is a fifth embodiment of the rectifier 1 of the present invention. In this embodiment, the dopant ion concentrations of the edge conduction type doped region 12B and the outer conduction type doped region 12C are both lower than the dopant ion concentration of each conduction type doped region 12A, and the edge conduction type doped region The doping ion depths of 12B and the outer conductive type doped region 12C are both greater than the doped ion depths of each conductive type doped region 12A. The structure of this embodiment can be manufactured according to the following process, using high-energy ion implantation to directly push dopant ions with a lower doping concentration (P-) to a relatively deep position in the conductive epitaxial layer 11 to form The edge conduction type doped region 12B and the outer edge conduction type doped region 12C; then, implanting doped ions with higher doping concentration (P+) into the conduction type epitaxial layer 11 to form the conduction type doped region 12A, And the doping depth of each conductive type doped region 12A is smaller than that of the edge conductive type doped region 12B and the outer edge conductive type doped region 12C.

In addition, the structure of the fifth embodiment can also be produced by the following process: first, implant dopant ions with a lower doping concentration (i.e. P-) into the conductive epitaxial layer 11, and use high temperature to push the dopant ions to Deeper position to form the edge conduction type doped region 12B and the outer edge conduction type doped region 12C; then, implant the doping ions with higher doping concentration (P+) into the conduction type epitaxial layer 11 to form The plurality of conductive type doped regions 12A, and the doping depth of each conductive type doped region 12A is smaller than the doping depth of the edge conductive type doped region 12B and the outer edge conductive type doped region 12C.

In short, the present invention can also utilize two-pass photomask design to form the conduction type doped region 12A, the edge conduction type doped region 12B and the outer edge conduction type doped region 12A with different doping concentrations and different doping depths. impurity region 12C; however, the rest of the process steps can refer to the first embodiment.

Please refer to FIG. 4 , which is a sixth embodiment of the rectifier 1 of the present invention. The difference between the sixth embodiment and the above-mentioned embodiments lies in the features of the edge conduction type doped region 12B and the outer edge conduction type doped region 12C. In this embodiment, the edge conduction type doped region 12B and the conduction type doped region 12A are P+ regions, and the outer edge conduction type doped region 12C includes a high-concentration outer edge conduction type doped region 12C' and a package The low-concentration peripheral conductivity-type doped region 12C″ covers the high-concentration peripheral conductivity-type doped region 12C′.

Please refer to FIG. 4A , which is a seventh embodiment of the rectifier 1 of the present invention. In this embodiment, the edge conduction type doped region 12B includes a high concentration edge conduction type doped region 12B' and a low concentration edge conduction type doped region 12B' covering the high concentration edge conduction type doped region 12B'. region 12B″, and the outer conductive type doped region 12C includes a high concentration outer conductive type doped region 12C′ and a low concentration outer conductive type doped region 12C′ covering the high concentration outer conductive type doped region 12C′ Type doped region 12C".

However, the structure of this embodiment can be fabricated according to the following process: high-energy ion implantation is used to push dopant ions with a lower doping concentration (P-) to a relatively deep position in the conductive epitaxial layer 11 to form a A low-concentration edge conduction-type doped region 12B″ and a low-concentration outer-edge conduction-type doped region 12C″; then, implant dopant ions with a higher doping concentration (P+) into the conduction-type epitaxial layer 11 to Forming the multiple conductivity type doped regions 12A, a high concentration edge conductivity type doped region 12B′ and a high concentration outer edge conductivity type doped region 12C′, the high concentration edge conductivity type doped region 12B′ formed in the low-concentration edge conduction type doped region 12B″ to form the edge conduction type doped region 12B; and the high concentration outer edge conduction type doped region 12C′ is formed in the low concentration edge conduction type doped region In the impurity region 12C″, the peripheral conduction type doped region 12C is constructed.

In addition, the structure of the seventh embodiment can also be produced by the following process: implanting dopant ions with a lower doping concentration (P-) into the conductive epitaxial layer 11, and using high temperature to push the dopant ions to a deeper position to form a low-concentration edge conduction type doped region 12B" and a low-concentration outer edge conduction type doped region 12C"; then, implant dopant ions with a higher doping concentration (P+) into the conduction type layer 11 to form a conductive doped region 12A, a high-concentration edge-conductive-type doped region 12B′ and a high-concentration peripheral-conductive-type doped region 12C′, and a high-concentration edge-conductive-type doped region 12B 'formed in the low-concentration edge-conduction-type doped region 12B'' to form the edge-conduction-type doped region 12B; In the doped region 12C″, the peripheral conductivity type doped region 12C is constructed.

Therefore, the seventh embodiment also utilizes two photomasks to make the edge conduction type doped region 12B and the outer edge conduction type doped region 12C have high concentration and low concentration of dopant ions. By changing the doping concentration and doping depth, the rectifier 1 of the present invention can further enhance the impact resistance of the edge of the device to the reverse surge; however, other process steps in this embodiment can refer to the first embodiment.

In summary, the present invention has the following advantages: the rectifier 1 can provide high-efficiency operation under high temperature conditions, and the high efficiency comes from the operating characteristics of low voltage (low VF), for example, when the rectifier 1 has a forward current of 100 amperes, It has a forward voltage of 0.25 to 0.7 volts. In addition, the reverse leakage current (IR) measured by the rectifier 1 at room temperature is less than or equal to 100nA (optimally around 40nA), making it suitable for high temperature operating environments. In a high temperature environment above 125°C (125°C to 225°C), such as applied to a power supply system of an automobile, such as an alternator system. Moreover, the present invention further utilizes the structure of the edge conduction type doped region 12B and the outer edge conduction type doped region 12C to improve the impact resistance of the surrounding part of the rectifier 1 to the reverse surge.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the claims of the present invention. Therefore, all equivalent changes made by using the description of the present invention and the contents of the accompanying drawings are all included in the claims of the present invention. within range.

Claims (9)

1. a rectifier that is applied under the hot conditions is characterized in that, comprising:

One conductive-type semiconductor base material;

One conductivity type epitaxial loayer, it is positioned on this conductive-type semiconductor base material;

A plurality of conductivity type doped regions, it forms in this conductivity type epitaxial loayer;

One edge conductivity type doped region, it forms in this conductivity type epitaxial loayer and centers on described a plurality of conductivity type doped regions;

At least one outer rim conductivity type doped region, it forms in this conductivity type epitaxial loayer and centers on this edge conductivity type doped region;

One the first metal layer, it is arranged on this conductivity type epitaxial loayer, and this first metal layer is covered in described a plurality of conductivity type doped region all sidedly, and this first metal layer is this edge conductivity type doped region of cover part at least; And

Second metal level with respect to this first metal layer, it is arranged at the back side of this conductive-type semiconductor base material.

2. the rectifier that is applied under the hot conditions as claimed in claim 1 is characterized in that: the width of this outer rim conductivity type doped region is more than the twice of technology minimum feature.

3. the rectifier that is applied under the hot conditions as claimed in claim 1, it is characterized in that: the dopant ion concentration of this edge conductivity type doped region and this outer rim conductivity type doped region is all less than the dopant ion concentration of each conductivity type doped region, and the dopant ion degree of depth of this edge conductivity type doped region and this outer rim conductivity type doped region is all greater than the dopant ion degree of depth of each conductivity type doped region.

4. the rectifier that is applied under the hot conditions as claimed in claim 1, it is characterized in that: the dopant ion concentration of this outer rim conductivity type doped region is all less than the dopant ion concentration of this edge conductivity type doped region and each conductivity type doped region, and the dopant ion degree of depth of this outer rim conductivity type doped region is all greater than the dopant ion degree of depth of this edge conductivity type doped region and each conductivity type doped region.

5. the rectifier that is applied under the hot conditions as claimed in claim 1, it is characterized in that: this edge conductivity type doped region comprises that the edge conductivity type doped region and of a high concentration coats the edge conductivity type doped region of low concentration of the edge conductivity type doped region of this high concentration, and this outer rim conductivity type doped region more comprises the outer rim conductivity type doped region of a high concentration and the outer rim conductivity type doped region of the low concentration of the outer rim conductivity type doped region of this high concentration of coating.

6. the rectifier that is applied under the hot conditions as claimed in claim 1 is characterized in that: this outer rim conductivity type doped region comprises that the outer rim conductivity type doped region and of a high concentration coats the outer rim conductivity type doped region of low concentration of the outer rim conductivity type doped region of this high concentration.

7. the rectifier that is applied under the hot conditions as claimed in claim 1 is characterized in that: this first metal layer covers this whole edge conductivity type doped regions.

8. the rectifier that is applied under the hot conditions as claimed in claim 1 is characterized in that: this first metal layer cover this edge conductivity type doped region area 1/2nd.

9. the rectifier that is applied under the hot conditions as claimed in claim 1, it is characterized in that: further comprise a separator, it is arranged on this conductivity type epitaxial loayer, to cover this edge conductivity type doped region and this outer rim conductivity type doped region that is not contacted by this first metal layer.

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