CN217239473U - Silicon carbide-based semiconductor device - Google Patents
Silicon carbide-based semiconductor device Download PDFInfo
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- CN217239473U CN217239473U CN202220546862.4U CN202220546862U CN217239473U CN 217239473 U CN217239473 U CN 217239473U CN 202220546862 U CN202220546862 U CN 202220546862U CN 217239473 U CN217239473 U CN 217239473U
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Abstract
The utility model provides a carborundum based semiconductor device, include: the silicon carbide epitaxial wafer is connected to the ohmic contact metal on one side surface; the silicon carbide epitaxial wafer is provided with at least one silicon carbide groove, and the side wall of each silicon carbide groove is provided with a shielding electric field dielectric layer; a Schottky contact metal I is arranged on each silicon carbide groove; a second Schottky contact metal connected to the other side of the silicon carbide epitaxial wafer; when the device is reversed, the electric field can be effectively shielded, and the reliability of the device is improved.
Description
[ technical field ] A
The utility model relates to a carborundum based semiconductor device.
[ background of the invention ]
Silicon carbide is an earlier discovered semiconductor material that is more suitable for use in high power devices than Si materials due to its superior physical and electrical properties. However, high-quality silicon carbide crystals are difficult to obtain due to the difficulty in growing materials, so that the development of silicon carbide devices lags behind that of Si for many years. In recent years, silicon carbide semiconductor devices have been developed and have been improved in terms of basic electrical characteristics, but since power devices produced from silicon carbide semiconductor materials have a shorter product history than Si-based materials, device structures have not yet matured completely, and device structures related to device reliability have yet to be researched and developed.
In power systems, reverse leakage current is an important analytical parameter for diodes. When the device is in reverse blocking, high reverse leakage current will cause large heat loss of the device, and when the heat loss reaches a certain level, thermal runaway occurs, thereby causing the failure of the device. Therefore, the reverse reliability of the device is particularly important, the reduction of the reverse leakage current of the device is also an important factor which must be considered in the design, an important structure which influences the reverse characteristic of the device is the schottky contact of the device, and for the schottky contact of different metals and silicon carbide materials, a great deal of research and reports have been carried out in many laboratories, however, a great deal of research shows that the influence of the surface state of the material exceeds the influence of the work function of the metal many times, so that the schottky contact is not ideal.
[ Utility model ] content
The to-be-solved technical problem of the utility model lies in providing a carborundum based semiconductor device, when reverse, can effectual shielding electric field, improves the reliability of device.
One of the utility model is realized like this: a silicon carbide-based semiconductor device comprising:
an ohmic contact metal is formed on the substrate,
a silicon carbide epitaxial wafer, one side of which is connected to the ohmic contact metal; the silicon carbide epitaxial wafer is provided with at least one silicon carbide groove, and the side wall of each silicon carbide groove is provided with a shielding electric field dielectric layer;
a first Schottky contact metal is arranged on each silicon carbide groove;
and the second Schottky contact metal is connected to the other side surface of the silicon carbide epitaxial wafer.
Further, the thickness of the shielding electric field dielectric layer is less than 0.2 micrometer.
Further, the depth of the silicon carbide trench 101 is 0.2 to 2 micrometers, and the angle is 15 ° to 90 °.
Furthermore, the Schottky diode further comprises a front thickened electrode and a back thickened electrode, wherein the front thickened electrode is connected to the second Schottky contact metal; the back-side thickened electrode is connected to the ohmic contact metal.
The utility model discloses second realizes like this: a silicon carbide-based semiconductor device comprising:
an ohmic contact metal is formed on the substrate,
a silicon carbide epitaxial wafer, one side of which is connected to the ohmic contact metal; the silicon carbide epitaxial wafer is provided with at least one silicon carbide groove, the bottom of each silicon carbide groove is provided with a P region structure, and the side wall of each silicon carbide groove is provided with a shielding electric field dielectric layer;
a Schottky contact metal I is arranged on each silicon carbide groove;
and the second Schottky contact metal is connected to the other side surface of the silicon carbide epitaxial wafer.
Further, the thickness of the shielding electric field dielectric layer is less than 0.2 micrometer.
Further, the depth of the silicon carbide groove is 0.2-2 microns, and the angle is 15-90 degrees.
Furthermore, the Schottky diode further comprises a front thickened electrode and a back thickened electrode, wherein the front thickened electrode is connected to the second Schottky contact metal; the back-side thickened electrode is connected to the ohmic contact metal.
The utility model has the advantages that: the utility model discloses a carborundum base semiconductor device for the reverse leakage current of control device to and improve the reliability of device when reverse, introduced a shielding electric field dielectric layer, this shielding electric field dielectric layer is in the both sides of sic slot, can change electric field distribution, and then the reverse characteristic of control product, great improvement the reliability of device.
[ description of the drawings ]
The present invention will be further described with reference to the following examples and drawings.
Fig. 1 is a schematic structural diagram of a first embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a second embodiment of the present invention.
[ detailed description ] embodiments
The embodiment of the utility model provides a through providing a carborundum base semiconductor device, solved the technical problem of device reliability among the prior art, realized introducing a shielding electric field dielectric layer, this shielding electric field dielectric layer is in the both sides of sic slot, can change electric field distribution, and then the reverse characteristic of control product, great improvement the technological effect of the reliability of device.
Example one
As shown in fig. 1, the present invention relates to a silicon carbide-based semiconductor device, including:
an ohmic contact metal 105 is formed on the substrate,
a silicon carbide epitaxial wafer 100, one side of said silicon carbide epitaxial wafer 100 being connected to said ohmic contact metal 105; the silicon carbide epitaxial wafer 100 is provided with at least one silicon carbide groove 101, and the side wall of each silicon carbide groove 101 is provided with a shielding electric field dielectric layer 102;
a first Schottky contact metal 103 is arranged on each silicon carbide groove 101;
a second schottky contact metal 104, the second schottky contact metal 104 being connected to the other side of the sic epitaxial wafer 100.
The thickness of the shielding electric field dielectric layer 102 is less than 0.2 micrometer, so that the shielding effect is good, and the function of the semiconductor device is not influenced.
The depth of the silicon carbide groove 101 is 0.2-2 microns, and the angle is 15-90 degrees, so that the function of the silicon carbide device is better.
In another preferred embodiment, a sic-based semiconductor device further includes a front side thickened electrode 106 and a back side thickened electrode 107, wherein the front side thickened electrode 106 is connected to the schottky contact metal two 104; the backside thickened electrode 107 is connected to the ohmic contact metal 105.
The manufacturing method of the silicon carbide device comprises the following steps:
1. taking a silicon carbide epitaxial wafer 100;
2. the method of photoetching and dry etching is adopted to finish the process of pattern transfer, and finally a silicon carbide groove 101 is etched on the surface of the silicon carbide epitaxial wafer 100, wherein the depth of the silicon carbide groove 101 is 0.2-2 um, and the angle is 15-90 degrees;
3. a field-shielding dielectric layer 102 is grown on the silicon carbide epitaxial wafer 100, and may be formed by PECVD deposition or oxide growth. Etching the whole wafer, and only reserving a side wall part to form a final structure shielding electric field dielectric layer 102, wherein the thickness of the shielding electric field dielectric layer 102 on the side wall is less than 0.2 um;
4. cleaning a silicon carbide epitaxial wafer by a cleaning process before metal deposition, then depositing Schottky metal, photoetching and stripping to finish a pattern transfer process, finally forming a Schottky metal I103 only in the groove, and quickly annealing to enable the Schottky metal I103 to form Schottky contact with silicon carbide at the bottom of a silicon carbide groove 101;
5. the front surface of the silicon carbide epitaxial wafer 100 is coated with glue for protection, and the back surface is deposited with metal Ni to form ohmic contact metal 105 with the silicon carbide epitaxial wafer 100;
6. cleaning the silicon carbide epitaxial wafer 100 by a cleaning process before metal deposition, depositing Schottky metal on the surface of the silicon carbide epitaxial wafer 100 to form a second Schottky contact metal 104, and performing rapid annealing to form Schottky contact with the surface of the silicon carbide epitaxial wafer 100;
7. depositing PAD metal such as metal Al or Ag on the surface of the second Schottky contact metal 104 to form a front thickened electrode 106;
8. the front side thickened electrode 106 is coated with glue for protection, organic cleaning is carried out on the surface of the ohmic contact metal 105, metal such as Al, Ag, Au and the like is deposited on the surface of the ohmic contact metal 105 to form a back side thickened electrode 107, finally organic cleaning is carried out, the previous glue is cleaned, and the preparation is finished.
Example two
As shown in fig. 2, the present invention relates to a silicon carbide-based semiconductor device, including:
an ohmic contact metal 105 is formed on the substrate,
a silicon carbide epitaxial wafer 100, one side of said silicon carbide epitaxial wafer 100 being connected to said ohmic contact metal 105; the silicon carbide epitaxial wafer 100 is provided with at least one silicon carbide groove 101, the bottom of each silicon carbide groove 101 is provided with a P region structure 108, and the side wall of each silicon carbide groove 101 is provided with a shielding electric field dielectric layer 102;
a first Schottky contact metal 103 is arranged on each silicon carbide groove 101;
a second schottky contact metal 104, the second schottky contact metal 104 being connected to the other side of the sic epitaxial wafer 100.
The thickness of the shielding electric field dielectric layer 102 is less than 0.2 micrometer, so that the shielding effect is good, and the function of the semiconductor device is not influenced.
The depth of the silicon carbide groove 101 is 0.2-2 microns, and the angle is 15-90 degrees, so that the function of the silicon carbide device is better.
In another preferred embodiment, a sic-based semiconductor device further includes a front side thickened electrode 106 and a back side thickened electrode 107, wherein the front side thickened electrode 106 is connected to the schottky contact metal two 104; the backside thickened electrode 107 is connected to the ohmic contact metal 105.
The manufacturing method of the silicon carbide device comprises the following steps:
1. taking a silicon carbide epitaxial wafer 100;
2. the method of photoetching and dry etching is adopted to finish the process of pattern transfer, and finally a groove 101 is etched on the surface of the silicon carbide epitaxial wafer, wherein the depth of the groove is 0.2-2 um, and the angle is 15-90 degrees;
3. and growing an oxide film on the surface of the silicon carbide epitaxial wafer, photoetching and etching to form an implantation mask, blocking by adopting the implantation mask, and forming a P region structure 108 at the bottom of the silicon carbide groove. After the P area injection structure is completed, removing the injection mask and carrying out a standard cleaning process;
4. activating and annealing the silicon carbide epitaxial wafer to activate the P region structure 108;
5. a field-shielding dielectric layer 102 is grown on the silicon carbide epitaxial wafer 100, and may be formed by PECVD deposition or oxide growth. Etching the whole wafer, and only reserving a side wall part to form a final structure shielding electric field dielectric layer 102, wherein the thickness of the shielding electric field dielectric layer 102 on the side wall is less than 0.2 um;
6. cleaning a silicon carbide epitaxial wafer by a cleaning process before metal deposition, then depositing a first Schottky metal 103, photoetching and stripping to finish a pattern transfer process, finally forming the first Schottky metal 103 only in the groove, and quickly annealing to enable the first Schottky metal 103 to form Schottky contact with silicon carbide at the bottom of the groove;
7. the front surface of the silicon carbide epitaxial wafer 100 is coated with glue for protection, and the back surface is deposited with metal Ni to form ohmic contact metal 105 with the silicon carbide epitaxial wafer 100;
8. cleaning the silicon carbide epitaxial wafer 100 by a cleaning process before metal deposition, depositing Schottky metal on the surface of the silicon carbide epitaxial wafer 100 to form a second Schottky contact metal 104, and quickly annealing to form Schottky contact with the surface of the silicon carbide epitaxial wafer 100;
9. depositing PAD metal such as metal Al or Ag on the surface of the second Schottky contact metal 104 to form a front thickened electrode 106;
10. the front side thickened electrode 106 is coated with glue for protection, organic cleaning is carried out on the surface of the ohmic contact metal 105, metal such as Al, Ag, Au and the like is deposited on the surface of the ohmic contact metal 105 to form a back side thickened electrode 107, finally organic cleaning is carried out, the previous glue is cleaned, and the preparation is finished.
Although specific embodiments of the present invention have been described, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the claims appended hereto.
Claims (8)
1. A silicon carbide-based semiconductor device, characterized by: comprises that
An ohmic contact metal is formed on the substrate,
a silicon carbide epitaxial wafer, one side of which is connected to the ohmic contact metal; the silicon carbide epitaxial wafer is provided with at least one silicon carbide groove, and the side wall of each silicon carbide groove is provided with a shielding electric field dielectric layer;
a first Schottky contact metal is arranged on each silicon carbide groove;
and the second Schottky contact metal is connected to the other side surface of the silicon carbide epitaxial wafer.
2. A silicon carbide-based semiconductor device according to claim 1, wherein: the thickness of the shielding electric field dielectric layer is less than 0.2 micrometer.
3. A silicon carbide-based semiconductor device according to claim 1, wherein: the depth of the silicon carbide groove is 0.2-2 microns, and the angle is 15-90 degrees.
4. A silicon carbide-based semiconductor device according to claim 1, wherein: the Schottky diode further comprises a front thickened electrode and a back thickened electrode, wherein the front thickened electrode is connected to the second Schottky contact metal; the back-side thickened electrode is connected to the ohmic contact metal.
5. A silicon carbide-based semiconductor device, characterized by: comprises that
An ohmic contact metal is formed on the substrate,
a silicon carbide epitaxial wafer, one side of which is connected to the ohmic contact metal; the silicon carbide epitaxial wafer is provided with at least one silicon carbide groove, the bottom of each silicon carbide groove is provided with a P region structure, and the side wall of each silicon carbide groove is provided with a shielding electric field dielectric layer;
a Schottky contact metal I is arranged on each silicon carbide groove;
and the second Schottky contact metal is connected to the other side surface of the silicon carbide epitaxial wafer.
6. A silicon carbide-based semiconductor device according to claim 5, wherein: the thickness of the shielding electric field dielectric layer is less than 0.2 micrometer.
7. A silicon carbide-based semiconductor device according to claim 5, wherein: the depth of the silicon carbide groove is 0.2-2 microns, and the angle is 15-90 degrees.
8. A silicon carbide-based semiconductor device according to claim 5, wherein: the Schottky diode further comprises a front thickened electrode and a back thickened electrode, wherein the front thickened electrode is connected to the second Schottky contact metal; the back-side thickened electrode is connected to the ohmic contact metal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202220546862.4U CN217239473U (en) | 2022-03-14 | 2022-03-14 | Silicon carbide-based semiconductor device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220546862.4U CN217239473U (en) | 2022-03-14 | 2022-03-14 | Silicon carbide-based semiconductor device |
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| CN217239473U true CN217239473U (en) | 2022-08-19 |
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