JPS6031112B2 - Schottky diode with PN junction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in Schottky diodes having PN junctions.

Conventionally, as a Schottky diode with a PN junction,
As shown in FIG. 1, the semiconductor substrate 3 has a structure in which, for example, an N- type semiconductor layer 2 is formed on an N+ type semiconductor substrate body 1. From the main surface 4 side, a P+ type semiconductor layer 5 is formed in a closed ring shape to form a PN junction 6 with the semiconductor layer 2, and is also connected to the semiconductor layer 5 of the semiconductor layer 2 of the semiconductor substrate 3. On the surface 8 facing the four main surfaces of the region 7 surrounded by the area 7 in a closed ring shape, and on the surface 9 facing the main surface 4 side of the semiconductor layer 5, a metal layer 10 common thereto is formed. It is attached to form a Schottky junction 11 with the surface 8 and an ohmic contact 12 with the surface 9, and is further provided on the surface 13 of the semiconductor substrate body 1 of the semiconductor substrate 3 on the side opposite to the semiconductor layer 2 side. , a structure in which a conductive layer 14 is attached to form an ohmic contact 15 with the surface 13 has been proposed.

In FIG. 1, 16 indicates the main surface 4 of the semiconductor layer 2 of the semiconductor substrate 3 so that the metal layer 10 is applied only on the surfaces 8 and 9.
It is an insulating layer formed on top.

Conventionally, as shown in FIG. 2, in the configuration described above in FIG. Similar to the semiconductor layer 5, a P+ type semiconductor layer 17 is formed from the main surface 4 side in a closed IJ shape to form a PN junction 18 with the region 7 of the semiconductor layer 2. layer 2 semiconductor layer 1
In the region 19 surrounded by the region 7 in a closed ring shape, a P+ type semiconductor layer 20 forms a PN post-contact 21 with the region 19 of the semiconductor layer 2, similar to the semiconductor layers 5 and 17. On the surface 8 facing the main surface 4 side of the region 7 formed as shown in FIG.
And on the surface 9 facing the main surface 4 of the semiconductor layer 5, a metal layer 10 is attached to form a Schottky junction 11 with the surface 8 and an ohmic contact 12 with the surface 9. Ohmic contacts 24 are also formed on the surfaces 22 and 23 of the layers 17 and 20 facing the main surface side 4 between the surfaces 22 and 23, respectively.
A configuration similar to that described above with reference to FIG. 1 has also been proposed, except that it is attached to form . By the way, according to the configuration of the Schottky diode having the PN junction described above in FIGS. 1 and 2, the semiconductor substrate 3 and the semiconductor layer 5 of the semiconductor layer 2 are surrounded in a closed ring shape. With a metal layer 10 applied to form a Schottky junction 11 on the surface 8 of the region 7 and a conductive layer 14 applied to form an ohmic contact 15 to the semiconductor substrate body 1 of the semiconductor substrate 3. , which constitutes a Schottky diode element.

Also, the PN junction (PN junction 6 in Figure 1, PN junctions 6, 18, and 21 in Figure 2) constitutes a Schottky diode having a PN junction, but it is a semiconductor. A substrate 3 and a semiconductor layer formed in the semiconductor layer 2 to form a PN junction from the main surface 4 side (semiconductor layer 5 in the case of FIG. 1, semiconductor layers 5, 17 in the case of FIG. 2).
and 20), and the plane of the semiconductor layer (plane 9 in the case of FIG. 1,
In the case of FIG. 2, a metal layer 10 is applied to form an ohmic contact on the surfaces 9, 22 and 23), and a conductive layer is applied to form an ohmic contact 15 to the semiconductor substrate body 1 of the semiconductor substrate 3. 14 constitutes a PN junction diode element.

Therefore, the Schottky diode having a PN junction described above in FIGS. 1 and 2 has a composite diode configuration in which a Schottky diode element and a PN junction diode element are equivalently connected in parallel with each other with the same polarity. It is. Further, according to the configuration of the Schottky diode having the PN junction described above in FIGS. 1 and 2, it has a composite diode configuration as described above, but there is By using these as electrodes and applying a reverse voltage with the metal layer 10 side being negative, the PN junction included in the PN junction diode element (PN junction 6 in FIG. 1, PN junctions 6 and 18 in FIG. 2) and 21),
A depletion layer is generated in the region below the Schottky junction 11 included in the Schottky diode element in the region 7 surrounded by the semiconductor layer 5 of the semiconductor layer 2 of the semiconductor substrate 3 in a closed shape, and thus, The depletion layer expands as the reverse voltage increases, and finally the depletion layer expands to the entire region below the Schottky junction 11 in the region 7.

Therefore, when a reverse voltage is applied to the Schottky diode having the PN junction described above in FIGS. 1 and 2, the side of the conductive layer 14 increases as the reverse voltage increases. The reverse current flowing toward the metal layer 10 side is further reduced, and the reverse current no longer flows, which is a characteristic that exhibits superior reverse voltage-current characteristics compared to a normal Schottky diode without a PN junction. It is something that you have. Furthermore, in the case of the Schottky diode structure having the PN junction described above in FIGS. 1 and 2, the side of the metal layer 10 where they are applied as electrodes between the metal layer 10 and the conductive layer 14 is assumed to be positive. Looking at the relationship between the forward voltage (generally referred to as V) and the forward current flowing from the metal layer 10 side to the conductive layer 14 side (this is assumed to be 1), it is found that The relationship between forward current 1 and forward voltage V exhibits a vertical voltage-current characteristic as shown by curve A in FIG. Generally, as shown by curve B in FIG. 3, the relationship between the forward direction current 1 and the forward direction current 1 of the Schottky diode element itself decreases in the range below a certain value of the daily direction voltage V (generally referred to as Vf). Even if the value is less than the value of In the range below the value Vf of the forward voltage V, it is governed by the forward voltage-current characteristics of the Schottky diode element, but in the range above the value Vf of the forward voltage V, it is a PN junction diode. A combination of the forward voltage-current characteristics of a Schottky diode element and the forward voltage-current characteristics of a PN junction diode element, which are dominated by the forward voltage-current characteristics of the element, results in a composite forward voltage-current characteristic. It is something.

For this reason, in the case of a Schottky diode having a PN junction as described above in FIGS. A relatively large amount of minority carriers are injected into the region 7 surrounded by the semiconductor layer 5 of the semiconductor layer 2 of the semiconductor substrate 3 in a closed shape from the PN junction included in the diode element, and then, This is stored in area 7. Therefore, P as described above in FIGS. 1 and 2
A Schottky diode having an N junction has the disadvantage that high-speed operation is limited by the minority carrier accumulation effect described above.

Therefore, the present invention relates to the PN described above in FIGS. 1 and 2.
Although it exhibits excellent reverse voltage-current characteristics similar to that of a Schottky diode with a junction, it does not have the effect of accumulating minority carriers as in the case of a Schottky diode with a PN junction as described above in FIGS. 1 and 2. This will become clear from the detailed description below.

FIG. 4 shows a first embodiment of a Schottky diode having a PN junction according to the present invention, for example, a semiconductor substrate having a structure in which an N- type semiconductor layer 42 is formed on an N+ type semiconductor substrate body 41. 43, and a semiconductor layer stack 45 is formed in the semiconductor layer 42 from the main surface 44 side in a closed ring shape. In this case, the semiconductor layer stack 45 includes a plurality of, for example, three semiconductor layers L, L2, and L3 each including a P-type semiconductor layer and an N-type semiconductor layer.
(In this case, the semiconductor layer L, is P type, the semiconductor layer L2 is N type,
The semiconductor layer L3 has a P-type), but the semiconductor layers L
〜L3, connect two PN junctions J and J2 one less than those number to the main surface 44 from the opposite side to the main surface 44 side.
In order to sequentially form the same D-like closed ring shape when viewed from the side, the outermost semiconductor layer L (having P type) of the semiconductor layers L to L and the semiconductor layer 42 (N-type )
When viewed from the main surface 44 side, one PN junction Jo is formed concentrically with the above-mentioned PN junctions J and J2 in a closed ring shape.
In order to form a closed ring concentrically with the joints J and J2,
P-type semiconductor layers and N-type semiconductor layers are alternately arranged on the main surface 4.
A mode in which semiconductor layers L, L2, and L3 are laminated concentrically in a closed ring shape when viewed from the main surface 44 side (semiconductor layers L, L2, and L3 are stacked concentrically in a closed ring shape when viewed from the main surface 44 side). (a mode in which the substrates are sequentially laminated).

In fact, the semiconductor layer stack 45 having such a configuration has the following structure:
A P-type semiconductor layer whose outer part becomes the semiconductor layer L described above,
A P-type impurity introduction process (for example, a diffusion process) is performed to form a closed ring, and then, within the P-type semiconductor layer, an N-type semiconductor layer whose outer portion becomes the semiconductor layer L2 described above is added. Similarly, it is formed into a closed IJ ring shape by introducing mold impurities,
Next, in the N-type semiconductor layer, a P+-type semiconductor layer, which becomes the semiconductor layer described above, is similarly formed in a closed ring shape by introducing P-type impurities. be.

Thus, the main surface 4 of the region 46 surrounded by the semiconductor layer stack 45 of the semiconductor layer 42 of the semiconductor substrate 43 in the shape of a closed IJ ring.
On the surface 47 facing the fourth side and on the surface 48 facing the main surface 44 side of the innermost semiconductor layer L3 of the semiconductor layers L to L3 of the semiconductor layer stack 45, a metal layer 49 common to them is provided. A surface 4 facing the main surface 44 side of a region 46 surrounded in a closed ring shape by the semiconductor layer stack 45 of the semiconductor layer 42 of the semiconductor substrate 43
The Schottky junction 50 is formed only between the main surface 4 of the innermost semiconductor layer of the semiconductors L to L3 of the semiconductor layer stack 45.
It is attached in order to form an ohmic contact 51 only with the surface 48 facing the 4th side.

Further, the semiconductor layer 4 of the semiconductor substrate body 41 of the semiconductor substrate 43
A conductive layer 53 is formed on the surface 52 opposite to the surface 51.
It is attached to form an ohmic contact 54 between the two. In FIG. 4, 55 indicates the semiconductor layer 42 of the semiconductor substrate 43 so that the metal layer 49 is applied only to the surfaces 47 and 48.
This is an insulating layer formed on the main surface 44 of.

The above is the configuration of the first embodiment of the Schottky diode having a PN junction according to the present invention.

According to such a configuration, the semiconductor substrate 43 and the semiconductor layer 4
A metal layer 49 attached to form a Schottky junction 50 on the surface 47 of the region 46 surrounded by the semiconductor layer stack 45 of No. 2 in a closed ring shape, and a metal layer 49 attached to the semiconductor substrate body 41 of the semiconductor substrate 43. A Schottky diode element is constituted by a conductive layer 53 attached to form an ohmic contact 54. Also, PN junctions Jo, J, and J
2 is a Schottky diode having a PN junction, which constitutes the PN junction, and the semiconductor substrate 43
, mutually identical closed ring-shaped semiconductor layers L, L2, and L3 of the semiconductor stack 45 formed in the semiconductor layer 42 in a closed shape from the main surface 44 side, and the semiconductor layer 42. A metal layer 49 is attached to form an ohmic contact 51 on the surface 48 of the semiconductor layer L3 of the laminate 45, and a conductive layer 53 is attached to the semiconductor substrate body 41 of the semiconductor substrate 43 to form an ohmic contact 54. These constitute a PNPN type thyristor element.

Therefore, the Schottky diode having a PN junction according to the present invention as shown in FIG. It is.

Further, in the Schottky diode having a PN junction according to the present invention as described above in FIG. If a reverse voltage is applied with the metal layer 49 side being negative using the metal layer 49 as an electrode, the semiconductor layer stack 45 of the semiconductor layer 42 of the semiconductor substrate 43 will be exposed to the closed ring-shaped PN junction Jo included in the PNPN type thyristor element. A depletion layer is generated in the region below the Schottky junction 50 included in the Schottky diode element in the region 46 surrounded by a closed ring, and the reverse voltage becomes large in the depletion layer. The depletion layer expands in a direction in which the depletion layer increases in accordance with the amount of the Schottky junction 50, and finally the depletion layer expands to the entire area under the Schottky junction 50 in the region 46.

Therefore, a Schottky diode with a PN junction according to the invention as described above in FIG. is applied, as the reverse voltage increases, the reverse current flowing from the conductive layer 53 side to the metal layer 49 side decreases,
Finally, the reverse current stops flowing, P
It is characterized by exhibiting superior reverse voltage-current characteristics compared to a normal Schottky diode that does not have an N junction.

Furthermore, according to the configuration of the Schottky diode having a PN junction according to the present invention as described above in FIG. Looking at the relationship between the forward current 1 flowing from the metal layer 49 side to the conductive layer 53 side with respect to the forward voltage V with the side positive, a curve in FIG. 3 as shown in curve A in FIG. Forward voltage shown in A -
It can be obtained as having the same directional voltage-current characteristics as the current characteristics.

In addition, when looking at the PNPN type thyristor element in terms of the relationship between the forward voltage V and the forward current 1, generally the value of the forward voltage V is set to a value relatively higher than zero (this VM), the value of the peak direction current 1 increases only slightly, with a value sufficiently smaller than the value of the forward direction current of the Schottky diode element. If the voltage is increased, the forward current 1 flows with a large value in the range of values smaller than the value of the forward current 1 of the Schottky diode element, which is the so-called thyristor characteristic. It is something that can be done.

Therefore, according to the configuration of the Schottky diode having a PN junction according to the present invention as described above in FIG. 4, the forward voltage V
Even in a range where the value is large, the Schottky diode element exhibits a forward voltage-current characteristic, which is dominated by the forward voltage-current characteristic.

For this reason, in the case of a Schottky diode having a PN junction according to the present invention as described above in FIG. Semiconductor layer stack 4 of semiconductor layer 42
Minority carriers are injected into the region 46 surrounded by the region 5 in a closed ring shape, and the minority carriers are not accumulated in the region 46.

Therefore, the Schottky diode with a PN junction according to the present invention as described above in FIG. This feature is characterized in that high-speed operation is not limited by this.

Thus, the Schottky diode with a PN junction according to the invention as described above in FIG. -While exhibiting current characteristics,
It has the excellent feature that high-speed operation is not limited by the accumulation effect of minority carriers, as is the case with the conventional Schottky diode having a PN junction as shown in FIGS. 1 and 2. It is something. Further, since the metal layer 49 is applied to form a Schottky junction only in the region 46 and is not applied to any semiconductor layer of the semiconductor stack 45, there is no need for a reverse current to flow through the semiconductor stack 45. It never flows.

Next, a second embodiment of a Schottky diode having a PN junction according to the present invention will be described with reference to FIG. 6. In this example, parts corresponding to those in FIG. 4 are given the same reference numerals. Although a detailed explanation will be omitted, in the configuration described above in FIG. To,
From the main surface 44 side, a semiconductor layer stack 60 (
In this semiconductor layer stack 6, a surface 48 facing the main surface 44 side of the semiconductor layer L3 is formed (portions corresponding to those of the semiconductor layer stack 45 are shown with the same reference numerals). 4, except that a metal layer 49 is applied on top to form an ohmic contact 61 with surface 48.

The above is the second embodiment of the Schottky diode having a PN junction according to the present invention, which is the same as the first embodiment of the present invention described above in FIG. 4, except for the matters mentioned above. In this case, in addition to the PNPN type thyristor element described above in FIG. 4, the semiconductor substrate 43, the mutually concentric semiconductor layers L, . 53 constitutes another PNPN type thyristor element, so a detailed explanation thereof will be omitted, but it has the same excellent features as the first embodiment of the present invention described above with reference to FIG. It is clear that it has

However, in the case of this example, the semiconductor layer stack 60 is formed in a region 46 surrounded by the semiconductor layer stack 45 of the semiconductor layer 42 of the semiconductor substrate 43 in a closed shape, and the semiconductor layer Since a PNPN type thyristor element including the stacked body 60 and the same PNPN type thyristor element as the PNPN type thyristor element configured including the semiconductor layer stacked body 45 is configured, the entire area under the Schottky junction 50 in the region 46 is removed by applying a reverse voltage. The reverse voltage in the case where a depletion layer spreading in the region is obtained is the fourth
The value is lower than that of the first embodiment of the present invention shown in the figure.
Therefore, the reverse voltage-current characteristic is more excellent than that of the first embodiment of the present invention shown in FIG. 4.

Next, a third embodiment of a Schottky diode having a PN junction according to the present invention will be described with reference to FIG. 7. In this example, parts corresponding to those in FIG. Although the explanation is omitted, in the configuration described above in FIG. 4, the semiconductor layer stack 45 includes three semiconductor layers L to L3.
(However, semiconductor layer L3 is P type) On top, two semiconductor layers L4
(N type) and L5 (P+ type) are sequentially stacked in a closed IJ ring shape in the same manner as the semiconductor layers L to - when viewed from the main surface 44 side. The metal layer 49 is replaced with the semiconductor layer stack 7 in this case.
The structure is similar to that of the case shown in FIG. 4, except that an ohmic contact 72 is formed only on the surface 71 facing the main surface 44 of the semiconductor layer L5. The above is the configuration of the third embodiment of the Schottky diode having a PN junction according to the present invention. is the same as in the first embodiment, and includes a semiconductor layer stack 70 to constitute a PNPNPN type element,
Since the element replaces the PNPN type thyristor element of the first embodiment of FIG. 4 and performs the same function, the same excellent characteristics as in the first embodiment of FIG. 4 can be obtained. It is something.

Next, a fourth embodiment of a Schottky diode having a PN junction according to the present invention will be described with reference to FIG. 8. In this example, parts corresponding to those in FIG. 7 are given the same reference numerals. Although a detailed explanation will be omitted, in the configuration described above in FIG. To,
From the main surface 44 side, a semiconductor layer stack 80 (
In this semiconductor layer stack 8, a corresponding portion with the semiconductor layer stack 70 is denoted by the same reference numeral) is formed, and the surface facing the main surface 44 side of the semiconductor layer L5 is formed. Also on 71, metal layer 49 makes ohmic contact 81 with surface 71.
It has the same structure as the case of FIG. 7, except that it is attached to form a .

The above is the fourth embodiment of the Schottky diode having a PN junction according to the present invention, which is the same as the third embodiment of the present invention described above in FIG. 7 except for the matters mentioned above. Yes, and in this case, P as described above in FIG.
In addition to the NPNPN type element, other PNPNPN type elements include the semiconductor substrate 43 and the semiconductor layer stack 80, so a detailed explanation thereof will be omitted. It is clear that this embodiment has the same excellent features as the third embodiment.

However, in the case of this example, the semiconductor layer stack 80 is formed within the region 46 surrounded by the semiconductor layer stack 7 of the semiconductor layer 42 of the semiconductor substrate 43 in a closed ring shape, and the semiconductor layer stack 80 is A PN similar to a PNPNPN type element that includes the layer stack 80 and includes the closed semiconductor layer stack 70.
Since a PNPN type element is configured, the reverse voltage when a depletion layer that spreads over the entire area under the Schottky junction 50 in the region 46 is obtained by applying a reverse voltage is
The value is lower than that of the third embodiment of the present invention shown in the figure.
Therefore, the reverse voltage-current characteristic is more excellent than that of the third embodiment of the present invention shown in FIG.

Next, a fifth embodiment of a Schottky diode having a PN junction according to the present invention will be described with reference to FIG. 9. In this example, parts corresponding to those in FIG. Although the explanation is omitted, in the configuration described above in FIG. The semiconductor layer stack 90' is replaced so that the metal layer 49 forms an ohmic contact 92 only on the surface 91 facing the main surface 44 of the semiconductor layer of the semiconductor layer stack 90 in this case. It has the same configuration as the case of FIG. 4 except for the addition. The above is the configuration of the fifth embodiment of the Schottky diode having a PN junction according to the present invention. It is similar to the case of the first embodiment shown in FIG.
It replaces the PN type thyristor element and performs the same function as the PN type thyristor element, so that excellent features similar to those of the first embodiment shown in FIG. 4 can be obtained.

Next, with reference to FIGS. 10 and 11, P according to the present invention will be described.
To describe a sixth embodiment of a Schottky diode having an N junction, in this example, corresponding parts to those in FIG. 9 are given the same reference numerals and detailed explanation thereof is omitted. In the configuration described above, the semiconductor layer 42 of the semiconductor substrate 43
The semiconductor layer stack 901 is placed in a region 46 surrounded by a closed ring shape from the main surface 44 side of the semiconductor layer stack 901.
A semiconductor layer stack 100 having a structure similar to 0 but not in a closed ring shape (in this semiconductor layer stack 10, parts corresponding to those of the semiconductor layer stack 90 are indicated with the same reference numerals) ) are distributed and formed, and the metal layer 49 is also formed on the surface 91 facing the main surface 44 side of the semiconductor layer L of the semiconductor layer stack 100, so that there is an ohmic contact between the metal layer 49 and the surface 91. contact 1
It has the same structure as the case of FIG. 9 except that it is attached to form 01.

The above is the sixth embodiment of the Schottky diode having a PN junction according to the present invention, which is the same as the first embodiment of the present invention described above in FIG. 9, except for the matters mentioned above. , and in this case, the NP mentioned above in FIG.
In addition to N-type elements, other NPs including the semiconductor layer stack 100
Since it constitutes an N-type element, a detailed explanation thereof will be omitted, but it is clear that it has the same excellent characteristics as the fifth embodiment of the present invention described above with reference to FIG. However, in the case of this example, a plurality of semiconductor layer stacks 100 are formed within a region 46 surrounded by a trowel-shaped semiconductor layer stack 90' of the semiconductor layer 42 of the semiconductor substrate 43, A semiconductor layer stack 90 including the semiconductor layer stack 100
Since the NPN type element is configured similar to the NPN type element configured by including the
The reverse voltage in the case where a depletion layer that spreads over the entire area under the Schottky junction 50 in FIG. 6 is lower than that in the case of the fifth embodiment of the present invention shown in FIG. This embodiment has the characteristic that the directional voltage-current characteristic is better than that of the fifth embodiment of the present invention shown in FIG.

Further, the semiconductor layer stack 9 of the semiconductor layer 42 of the semiconductor substrate 43
01 A plurality of semiconductor layer stacks 100 are formed within the region 46 surrounded by a closed iron ring shape, and since they are distributed and formed within the region 46, the reverse voltage In order to obtain the same depletion layer that spreads over the entire region under the Schottky junction 50 in the region 46 by applying When forming one semiconductor layer stack 100, the area occupied by the semiconductor layer stack 100' in the region 46 can be much smaller, and therefore, The area occupied by the Schottky junction 50 formed between the metal layer 49 and the surface 47 on the main surface 44 side of the region 46 in the region 46 is the same as the area occupied by the Schottky junction 50 formed between the metal layer 49 and the surface 47 of the region 46 on the main surface 44 side. Therefore, in order to obtain the same reverse voltage-current characteristics and forward voltage-current characteristics,
Assuming that the semiconductor layer stack 90 is formed in a closed ring shape, the size of the closed ring and therefore the size of the region 46 is:
It also has the advantage that the plurality of semiconductor layer stacks 100 can be made smaller than a single semiconductor layer stack, and therefore a Schottky diode having a PN junction can be formed in a small size on the semiconductor substrate 43. It is something that you have.

The above description only shows a few examples of the Schottky diode having a PN junction according to the present invention, and for example, the semiconductor layer stacks 60 and 80 described above in FIGS. In the same way as the semiconductor layer stack 100 is formed in a plurality in a distributed manner in the figures and FIG. Various other modifications and changes may be made without departing from the spirit of the invention.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic cross-sectional views showing a conventional Schottky diode having a PN junction, and FIG. 3 is a curve diagram showing its bottle direction voltage-current characteristics. FIG. 4 is a schematic cross-sectional view showing a first embodiment of a diode having a PN junction according to the present invention, and FIG. 5 is a curve diagram showing its daily directional voltage-current characteristics. Figure 6: Figure 7: Figure 8: and Figure 9 are schematic cross-sectional views showing second, third, fourth, and fifth embodiments of Schottky diodes having PN junctions according to the present invention, respectively. It is. 10 and 11 are a schematic plan view and a cross-sectional view, respectively, showing a sixth embodiment of a Schottky diode having a PN junction according to the present invention. In the figure, 41 is the semiconductor substrate body, 42
is a semiconductor layer, 43 is a semiconductor substrate, 44 is a main surface, 45, 6
0, 70, 80, 90 and 100 are semiconductor layer stacks, L
, ~L are semiconductor layers, Jo, J, ~J4 are PN junctions, 46
is a region, 49 is a metal layer, 50 is a Schottky junction, 51,
54, 61, 72, 81, 92 and 101 are ohmic contacts, 63 is a conductive layer, and 55 is an insulating layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 11 Figure 10

Claims (1)

[Claims] 1. A semiconductor layer stack is formed in a closed ring shape in a semiconductor substrate from the main surface side thereof, and the semiconductor layer stack includes a semiconductor layer having a first conductivity type, and a semiconductor layer having a first conductivity type. A plurality of semiconductor layers including a semiconductor layer having a second conductivity type opposite to the conductivity type of the plurality of semiconductor layers form PN junctions one less than the number of the semiconductor layers on the main surface side. In order to sequentially form a closed ring shape concentrically when viewed from the main surface, one PN junction is formed between the semiconductor layer at the end opposite to the main surface of the plurality of semiconductor layers and the semiconductor substrate. In order to form a closed ring shape concentrically with the PN junction when viewed from the surface side, semiconductor layers having a first conductivity type and semiconductor layers having a second conductivity type are alternately arranged one after the other when viewed from the main surface side. It has a structure in which layers are sequentially stacked concentrically in a closed ring shape, and the above-mentioned region of the semiconductor substrate is surrounded by the semiconductor layer stack in a closed ring shape. On the surface facing the main surface side and on the surface of the innermost semiconductor layer among the plurality of semiconductor layers of the semiconductor layer stack facing the main surface side, a metal layer common thereto is provided on the semiconductor substrate. In order to form a shot junction only between the surface facing the main surface side of the region surrounded by the semiconductor layered body in a closed ring shape, and to A Schottky diode having a PN junction, characterized in that it is attached to form ohmic contact only with the surface facing the main surface of the outer semiconductor layer. 2. A first semiconductor laminate is formed in a closed ring shape in a semiconductor substrate from its main surface side, and a region of the semiconductor substrate is surrounded by the first semiconductor layer laminate in a closed ring shape. A second semiconductor layer stack is formed inside the main surface from the main surface side, and the first semiconductor layer stack includes a semiconductor layer having a first conductivity type and a semiconductor layer having a conductivity type opposite to the first conductivity type. A plurality of semiconductor layers consisting of a semiconductor layer having a conductivity type of 2 is formed by a plurality of semiconductor layers having a conductivity type of
In order to form N junctions sequentially and concentrically in a closed ring shape when viewed from the main surface side, between the semiconductor layer at the end of the plurality of semiconductor layers opposite to the main surface side and the semiconductor substrate. In order to form one PN junction in a closed ring shape concentrically with the PN junction when viewed from the main surface side, semiconductor layers having a first conductivity type and semiconductor layers having a second conductivity type are alternately sequentially formed. The second semiconductor layer laminate has a structure in which the second semiconductor layer laminate has a first conductivity type. and a semiconductor layer having a second conductivity type opposite to the first conductivity type. In order to form the junctions sequentially and concentrically when viewed from the main surface side, one PN junction is formed between the semiconductor layer at the end of the plurality of semiconductor layers opposite to the main surface side and the semiconductor substrate. Semiconductor layers having a first conductivity type and semiconductor layers having a second conductivity type are alternately formed concentrically with the PN junction when viewed from both sides of the main surface. The main surface of the region of the semiconductor substrate surrounded by the first semiconductor layer laminate in a ring shape, A common metal layer is provided on the surface facing the side and on the surface facing the main surface of the innermost semiconductor layer among the plurality of semiconductor layers of the first and second semiconductor layer stacks. , in order to form a shot junction with a surface facing the main surface of a region surrounded by the first semiconductor layer stack of the semiconductor substrate in a closed ring shape, and A PN junction is provided to form an ohmic contact only with the surface facing the main surface of the innermost semiconductor layer among the plurality of semiconductor layers of the semiconductor laminate of No. 2. SHOTSUTOKI diode.