A hybrid conduction mechanism diode

Abstract

The present application provides a hybrid conduction mechanism diode, comprising: a first conductive type substrate layer; a first conductive type drift region, which is arranged on one side of the first conductive type substrate layer; a second conductive type body region, which is arranged on the side of the first conductive type drift region away from the first conductive type substrate layer; a germanium silicon region, which is arranged on the side of the first conductive type drift region away from the first conductive type substrate layer, wherein the second conductive type body region and the germanium silicon region are separated by the first conductive type drift region; an anode structure, which contacts the second conductive type body region, the first conductive type drift region and the germanium silicon region respectively; wherein, when forward conducting, a hole conduction channel is formed at the contact between the germanium silicon region and the anode structure. The present application can improve the device's large current conduction performance and single particle irradiation resistance performance through a hybrid conduction mechanism.

Description

Technical Field

[0001] The invention relates to the field of power semiconductor devices, and in particular to a hybrid conduction mechanism diode. Background Art

[0002] The Super Barrier Rectifier (SBR) was first proposed by engineers from APD in the United States in 2007. The SBR uses the upper metal as the anode, the lower substrate (N+substrate) is connected to the cathode, and a parallel PN junction diode (PIN) and a MOS transistor are integrated between the anode and the cathode to form a rectifier device; its forward turn-on voltage can be flexibly controlled by adjusting the threshold voltage of the MOS gate, and the reverse withstand voltage and leakage level utilize the reverse bias characteristics of the PN junction. Therefore, since the SBR utilizes a working principle different from that of conventional PIN and Schottky barrier diode (SBD) devices, it can simultaneously obtain rectifier characteristics of lower forward conduction voltage drop, smaller reverse leakage level, higher temperature stability and shorter recovery time.

[0003] The Schottky contact superbarrier rectifier (SSBR) is an improvement on the superbarrier rectifier (SBR). The SSBR has the advantages of the conventional SBR and integrates the parallel PIN diode and MOS channel between the anode and the cathode through the Schottky contact to form a rectifier device. Its forward turn-on voltage can be more flexibly controlled by adjusting the threshold voltage of the Schottky contact and the MOS gate. The reverse withstand voltage and leakage level utilize the reverse bias characteristics of the PN junction, and the barrier lowering effect caused by the image charge in the direct Schottky contact is suppressed. However, the SSBR still has the problem of poor single particle irradiation resistance. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention proposes a hybrid conduction mechanism diode, which mainly solves the problem that the existing devices have poor single particle irradiation resistance performance.

[0005] In order to achieve the above purpose and other purposes, the technical solution adopted by the present invention is as follows.

[0006] The present application provides a hybrid conduction mechanism diode, comprising: a first conductive type substrate layer; a first conductive type drift region, which is arranged on one side of the first conductive type substrate layer; a second conductive type body region, which is arranged on the side of the first conductive type drift region away from the first conductive type substrate layer; a germanium silicon region, which is arranged on the side of the first conductive type drift region away from the first conductive type substrate layer, wherein the second conductive type body region and the germanium silicon region are separated by the first conductive type drift region; an anode structure, which contacts the second conductive type body region, the first conductive type drift region and the germanium silicon region respectively; wherein, when forward conducting, a hole conduction channel is formed at the contact between the germanium silicon region and the anode structure.

[0007] In one embodiment of the present application, the anode structure includes: a gate oxide layer, which is arranged on the side of the first conductive type drift region away from the first conductive type substrate layer, and the gate oxide layer contacts the first conductive type drift region and the second conductive type body region respectively; a first conductive type polysilicon layer, which is arranged on the side of the gate oxide layer away from the first conductive type drift region; a metal anode region, which bridges the gate oxide layer and the first conductive type polysilicon layer, and the metal anode region forms a Schottky contact with the second conductive type body region; wherein, when forward conductive, an electron conduction channel is formed at the contact between the gate oxide layer and the second conductive type body region.

[0008] In an embodiment of the present application, the silicon germanium region is a heavily doped second conductivity type silicon germanium region.

[0009] In an embodiment of the present application, the doping concentration of the first conductive type substrate layer is higher than the doping concentration of the first conductive type drift region.

[0010] In one embodiment of the present application, a first conductive type buffer layer is further included, which is arranged between the first conductive type substrate layer and the first conductive type drift region.

[0011] In an embodiment of the present application, the doping concentration of the first conductive type buffer layer is between the doping concentration of the first conductive type substrate layer and the doping concentration of the first conductive type drift region.

[0012] In one embodiment of the present application, the anode structure includes a plurality of anode structures, and the anode structures are arranged at intervals.

[0013] In an embodiment of the present application, a cathode structure is further provided on a side of the first conductive type substrate layer away from the first conductive type drift region.

[0014] In an embodiment of the present application, the doping concentration of the second conductive type silicon germanium region is higher than the doping concentration of the first conductive type drift region.

[0015] As described above, the hybrid conduction mechanism diode provided by the present invention has the following beneficial effects.

[0016] The present application sets a germanium silicon region between the drift region and the anode structure, and provides a hole conduction channel through the germanium silicon region. When the device is turned on in the forward direction, the electron conduction channel and the hole conduction channel form a mixed conduction mechanism, thereby improving the forward large current conduction capability and surge reliability. At the same time, when the device is subjected to single-particle irradiation, the germanium silicon region can provide a hole channel, so that the holes generated by the single-particle effect flow out of the device from this region under the action of the electric field, and the device is not prone to single-particle gate penetration, which greatly improves the device's resistance to single-particle irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a cross-sectional view of the structure of a mixed conduction mechanism diode in one embodiment of the present application.

[0018] Figure 2 FIG. 4 is a cross-sectional view of a diode provided with a buffer layer in one embodiment of the present application.

[0019] 1-metal anode region, 2-first conductivity type polysilicon layer, 3-gate oxide layer, 4-second conductivity type body region, 5-first conductivity type drift region, 6-first conductivity type substrate layer, 7-germanium silicon region, 8-first conductivity type buffer layer. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0022] See also Figure 1 , Figure 1The cross-sectional view of the structure of the hybrid conduction mechanism diode in one embodiment of the present application. The diode includes: a first conductive type substrate layer 6, a first conductive type drift region 5, a germanium silicon region 7, a second conductive type body region 4 and an anode structure. The first conductive type drift region 5 is arranged on one side of the first conductive type substrate layer. The second conductive type body region 4 is arranged on the side of the first conductive type drift region 5 away from the first conductive type substrate layer, and the germanium silicon region 7 is arranged on the side of the first conductive type drift region 5 away from the first conductive type substrate layer, wherein the second conductive type body region 4 and the germanium silicon region 7 are separated by the first conductive type drift region 5. The anode structure contacts the second conductive type body region 4, the first conductive type drift region 5 and the germanium silicon region 7 respectively.

[0023] In one embodiment, a cathode structure may be further provided on a side of the first conductive type substrate layer 6 facing away from the first conductive type drift region 5 , and an external circuit may be connected via the anode structure and the cathode structure.

[0024] In one embodiment, the first conductivity type may be N type, and the second conductivity type may be P type.

[0025] In one embodiment, the anode structure includes: a gate oxide layer 3, a first conductive type polysilicon layer 2 and a metal anode region 1. The gate oxide layer 3 is arranged on the side of the first conductive type drift region 5 away from the first conductive type substrate layer 6, and the gate oxide layer 3 contacts the first conductive type drift region 5 and the second conductive type body region 4 respectively; the first conductive type polysilicon layer 2 is arranged on the side of the gate oxide layer 3 away from the first conductive type drift region 5; the metal anode region 1 is connected across the gate oxide layer 3 and the first conductive type polysilicon layer 2, and the metal anode region 1 forms a Schottky contact with the second conductive type body region 4. The gate oxide layer 3 can completely cover the first conductive type drift region 5 and partially cover the second conductive type body region 4, so that the gate oxide layer 3 contacts the first conductive type drift region 5 and the second conductive type body region 4 at the same time. The remaining contact surface of the second conductive type body region 4 not covered by the gate oxide layer 3 contacts the metal anode region 1. Since the germanium silicon region 7 and the second conductivity type body region 4 are located on different sides of the gate oxide layer 3, the metal anode region 1 is epitaxially extended from the second conductivity type body region 4, and extends to the germanium silicon region 7 via the surface of the first conductivity type polysilicon layer 2 away from the gate oxide layer 3 to form a bridging structure. The gate oxide layer 3 serves as the gate of the diode MOS structure, the first conductivity type substrate layer 6 serves as the source of the MOS structure, and the second conductivity type body region 4 serves as the MOS channel. When the diode is in a forward conduction state, an electron conduction channel is formed at the contact between the gate oxide layer 3 and the second conductivity type body region 4.

[0026] In one embodiment, there may be multiple anode structures, each of which is arranged at intervals on the same side. The arrangement of multiple anode structures facilitates mass production and can improve the manufacturing efficiency of the rectifier. The specific number of anode structures can be set and adjusted according to actual application requirements.

[0027] In one embodiment, the germanium silicon region 7 can be doped to form a heavily doped second conductivity type germanium silicon region, and by increasing the contact between the germanium silicon region 7 and the metal anode region 1, when the device is turned on in the forward direction, a hole conduction channel is formed at the contact between the germanium silicon region 7 and the metal anode region 1, and a mixed conduction mechanism is formed through the electron conduction channel and the hole conduction channel. The turn-on voltage of the hole conduction channel can be adjusted by adjusting the size and doping concentration of the germanium silicon region 7. Similarly, the turn-on voltage of the electron conduction channel can be adjusted by adjusting the doping concentration of the second conductivity type body region 4, which can meet the forward conduction performance requirements and single particle irradiation resistance performance requirements of different application scenarios. In addition, the setting of the germanium silicon region 7 can optimize the internal electric field distribution of the device, thereby increasing the breakdown voltage of the device.

[0028] In one embodiment, the doping concentration of the germanium silicon region 7 can be set to be higher than the doping concentration of the first conductive type drift region 5. When the device is turned on in the forward direction, since the forward conduction voltage of the diode structure formed by the germanium silicon and the first conductive type drift region 5 will be higher, the electron conduction channel will be turned on first, and the hole conduction channel will be turned on later, which can greatly improve the forward large current conduction capability and surge reliability. When the device is subjected to single particle irradiation, the germanium silicon region 7 can provide a hole conduction channel, so that the holes generated by the single particle effect flow out of the device from the hole conduction channel under the action of the electric field, and the device is not prone to single particle gate penetration, which can greatly improve the device's resistance to single particle irradiation.

[0029] In one embodiment, the thickness of each layered structure in the hybrid conduction mechanism diode can be set and adjusted according to actual application requirements. For example, the thickness of the gate oxide layer 3 can be set to 9 nanometers.

[0030] In one embodiment, the first conductive type substrate layer 6, the first conductive type drift region 5 and the second conductive type body region 4 can all use silicon as the main material, and the germanium silicon region 7 uses germanium silicon as the main material. Each main material forms a corresponding layered structure by doping, wherein the first conductive type substrate layer 6, the second conductive type body region 4 and the germanium silicon region 7 can be obtained by heavy doping, the first conductive type drift region 5 can be obtained by light doping, and the first conductive type polysilicon layer 2 can also be obtained by heavy doping, so that the doping concentration of the first conductive type substrate layer 6 is higher than the doping concentration of the first conductive type drift region 5. The doping dose of the heavily doped second conductive type body region 4 is 3.5×10 13 cm -2 The doping concentration of the heavily doped first conductive type substrate layer 6 is 5×10 19 cm -3 The doping concentration of the lightly doped first conductivity type drift region 5 can be 5×10 15 cm -3-Thus, the doping concentration of the first conductive type substrate layer 6 is higher than the doping concentration of the first conductive type drift region 5. The doping concentration of each layer structure can also be adjusted according to requirements, which is not limited here.

[0031] See also Figure 2 , Figure 2 This is a cross-sectional view of a diode provided with a buffer layer in an embodiment of the present application. A first conductive type buffer layer 8 may also be provided between the first conductive type substrate layer 6 and the first conductive type drift region 5. It is provided between the first conductive type substrate layer 6 and the first conductive type drift region 5. Among them, the doping concentration of the first conductive type buffer layer 8 is between the doping concentration of the first conductive type substrate layer 6 and the doping concentration of the first conductive type drift region 5. By providing the first conductive type buffer layer 8, the internal electric field distribution of the device is further optimized, so that the reverse breakdown voltage of the diode is improved.

[0032] Based on the above technical solutions, the hybrid conduction mechanism diode of the present application can improve the forward large current conduction capability and surge reliability compared with the existing devices. Moreover, when the device is subjected to single particle irradiation, the heavily doped second conductivity type germanium silicon region 7 can provide a hole channel, so that the holes generated by the single particle effect flow out of the device from this region under the action of the electric field, and the device is not prone to single particle gate penetration, which greatly improves the device's resistance to single particle irradiation.

[0033] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A hybrid conduction mechanism diode, characterized in that: include: a first conductive type substrate layer; A first conductive type drift region, which is disposed on one side of the first conductive type substrate layer; A second conductive type body region, which is arranged on a side of the first conductive type drift region away from the first conductive type substrate layer; a germanium silicon region, which is arranged on a side of the first conductive type drift region away from the first conductive type substrate layer, wherein the second conductive type body region and the germanium silicon region are separated by the first conductive type drift region; the germanium silicon region is a heavily doped second conductive type germanium silicon region; and the doping concentration of the second conductive type germanium silicon region is higher than the doping concentration of the first conductive type drift region; an anode structure, contacting the second conductive type body region, the first conductive type drift region and the germanium silicon region respectively; The anode structure comprises: a gate oxide layer, which is arranged on a side of the first conductive type drift region away from the first conductive type substrate layer, and the gate oxide layer contacts the first conductive type drift region and the second conductive type body region respectively; a first conductive type polysilicon layer, which is arranged on a side of the gate oxide layer away from the first conductive type drift region; a metal anode region, which is bridged on the gate oxide layer and the first conductive type polysilicon layer, and the metal anode region forms a Schottky contact with the second conductive type body region; wherein, when forward conducting, an electron conduction channel is formed at the contact between the gate oxide layer and the second conductive type body region; the germanium silicon region and the second conductive type body region are respectively located on different sides of the gate oxide layer; When the forward current is on, a hole conduction channel is formed at the contact between the silicon-germanium region and the anode structure.

2. The hybrid conduction mechanism diode according to claim 1, characterized in that: The doping concentration of the first conductive type substrate layer is higher than the doping concentration of the first conductive type drift region.

3. The hybrid conduction mechanism diode according to claim 1, characterized in that: The invention also includes a first conductive type buffer layer, which is arranged between the first conductive type substrate layer and the first conductive type drift region.

4. The hybrid conduction mechanism diode according to claim 3, characterized in that: The doping concentration of the first conductive type buffer layer is between the doping concentration of the first conductive type substrate layer and the doping concentration of the first conductive type drift region.

5. The hybrid conduction mechanism diode according to claim 1, characterized in that: The anode structure includes a plurality of anode structures, and each of the anode structures is arranged at intervals.

6. The hybrid conduction mechanism diode according to claim 1, characterized in that: A cathode structure is further disposed on a side of the first conductive type substrate layer away from the first conductive type drift region.

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