阅读说明：本技术 一种三栅SiC横向MOSFET功率器件 (Three-gate SiC transverse MOSFET power device ) 是由 施广彦 秋琪 李昀佶 于 2021-01-12 设计创作，主要内容包括：本发明提供了一种三栅SiC横向MOSFET功率器件,包括SiC衬底,设有一衬底凹槽；SiC外延层,设有一外延凹槽；所述SiC外延层设于所述衬底凹槽内；P型阱区,设有介质槽,所述介质槽内设有沟道区；所述所述P型阱区设于所述外延凹槽内；栅极,所述栅极包括两个第一侧栅以及一顶栅,所述顶栅两端部分别连接至所述栅极的一端部的侧面,形成倒U型结构,所述顶栅和第一侧栅除顶部以及连接处外均被高k介质包围,所述倒U型结构设于所述介质槽内,且突出于所述介质槽；漏极以及源极,所述源极以及源极设于所述介质槽内,且设于所述U型结构两侧；解决SiC功率MOSFET阈值电压高、饱和工作时驱动电平高,驱动功耗大的问题。(The invention provides a three-gate SiC transverse MOSFET power device, which comprises a SiC substrate, wherein a substrate groove is formed in the SiC substrate; the SiC epitaxial layer is provided with an epitaxial groove; the SiC epitaxial layer is arranged in the substrate groove; the P-type well region is provided with a medium groove, and a channel region is arranged in the medium groove; the P-type well region is arranged in the epitaxial groove; the grid comprises two first side grids and a top grid, two end parts of the top grid are respectively connected to the side surface of one end part of the grid to form an inverted U-shaped structure, the top grid and the first side grid except the top part and the connection part are all surrounded by a high-k medium, and the inverted U-shaped structure is arranged in the medium groove and protrudes out of the medium groove; the source electrode and the source electrode are arranged in the medium groove and are arranged on two sides of the U-shaped structure; the problems of high threshold voltage, high driving level during saturation work and high driving power consumption of the SiC power MOSFET are solved.)

1. A tri-gate SiC lateral MOSFET power device is characterized in that: comprises that

The SiC substrate is provided with a substrate groove;

the SiC epitaxial layer is internally provided with an epitaxial groove; the SiC epitaxial layer is arranged in the substrate groove;

the P-type well region is internally provided with a medium groove, and a channel region is arranged in the medium groove; the P-type well region is arranged in the epitaxial groove;

the grid electrode comprises two first side grid electrodes and a top grid electrode, two end parts of the top grid electrode are respectively connected to the side surface of one end part of the grid electrode to form an inverted U-shaped structure, the top grid electrode and the first side grid electrode except the top part and the connection part are all surrounded by a high-k medium, and the inverted U-shaped structure is arranged in the medium groove and protrudes out of the medium groove;

the source electrode is arranged in the medium groove and is arranged on one side of the U-shaped structure;

and the source electrode is arranged in the medium groove and is arranged on the other side of the U-shaped structure.

2. A tri-gate SiC lateral MOSFET power device according to claim 1 in which: the grid still includes at least one second side bars, the even interval of second side bars is located two in the side bars, just second side bars end is connected to the top gate, the second side gate is all wrapped up by the high K medium outside being located the top gate junction.

3. A tri-gate SiC lateral MOSFET power device according to claim 2 in which: the thickness and the width of the first side gate and the second side gate are equal.

4. A tri-gate SiC lateral MOSFET power device according to claim 1 in which: the longitudinal depth of the medium groove is smaller than that of the P-type well region.

5. A tri-gate SiC lateral MOSFET power device according to claim 1 in which: the longitudinal depth of the first side gate is greater than or equal to the depth of the dielectric groove.

Technical Field

The invention relates to a tri-gate SiC lateral MOSFET power device.

Background

Silicon carbide (SiC) materials in SiC devices have received much attention and research due to their excellent physical properties. The high-temperature high-power electronic device has the advantages of high input impedance, high switching speed, high working frequency, high temperature and high pressure resistance and the like, and is widely applied to the aspects of switching regulated power supplies, high-frequency heating, automobile electronics, power amplifiers and the like.

However, the development of SiC power devices is severely restricted due to technical and economic problems of high threshold voltage, high driving voltage at saturation current, more material defects, low channel mobility, high cost, and the like.

Disclosure of Invention

The invention aims to solve the technical problems of providing a three-gate SiC lateral MOSFET power device, and solving the problems of high threshold voltage, high driving level in saturation work and high driving power consumption of the SiC power MOSFET.

The invention is realized by the following steps: a tri-gate SiC lateral MOSFET power device comprises

The SiC substrate is provided with a substrate groove;

the SiC epitaxial layer is internally provided with an epitaxial groove; the SiC epitaxial layer is arranged in the substrate groove;

the P-type well region is internally provided with a medium groove, and a channel region is arranged in the medium groove; the P-type well region is arranged in the epitaxial groove;

the grid electrode comprises two first side grid electrodes and a top grid electrode, two end parts of the top grid electrode are respectively connected to the side surface of one end part of the grid electrode to form an inverted U-shaped structure, the top grid electrode and the first side grid electrode except the top part and the connection part are all surrounded by a high-k medium, and the inverted U-shaped structure is arranged in the medium groove and protrudes out of the medium groove;

the source electrode is arranged in the medium groove and is arranged on one side of the U-shaped structure;

and the source electrode is arranged in the medium groove and is arranged on the other side of the U-shaped structure.

Furthermore, the grid still includes at least one second side bars, the even interval of second side bars is located two in the side bars, and a second side bars end is connected to the top gate, the second side gate is all wrapped up by the high K dielectric outside being located the top gate junction.

Further, the thickness and the width of the first side gate and the second side gate are equal.

Further, the longitudinal depth of the medium groove is smaller than the depth of the P-type well region.

Further, the longitudinal depth of the first side gate is greater than or equal to the depth of the dielectric groove.

The invention has the advantages that:

the SiC lateral device is provided with three connected gate structures, wherein each gate structure comprises a planar gate and two trench gates, a conductive channel is wrapped by the three gates from three directions, and a channel region is inverted from the three directions, so that the SiC lateral device can form enough inversion layer carrier concentration under the condition of lower gate voltage and has lower threshold voltage under the condition of the same current;

when the threshold voltage is exceeded and the gate voltage is gradually increased by the three connected gate structures, a circle of high-carrier-word-concentration channel surrounding the gate is formed, and the carrier concentration of an inversion layer is increased, so that the carrier concentration is increased and the current-carrying capacity is increased under the condition of the same gate voltage;

and the three connected gate structures can realize sufficiently low specific on-resistance when the gate voltage is low, so that the gate driving voltage is reduced during saturation work of the SiC transverse MOSFET power device, and the driving energy consumption of the power device is reduced.

Drawings

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

Fig. 1 is a top view of a tri-gate SiC lateral MOSFET power device of the present invention.

Fig. 2 is a top gate position elevation cut-away view of a tri-gate SiC lateral MOSFET power device of the present invention.

Fig. 3 is a side cut view of the gate location of a tri-gate SiC lateral MOSFET power device of the present invention.

FIG. 4 is a schematic diagram of the second embodiment.

Detailed Description

The invention provides a tri-gate SiC transverse MOSFET power device, which is used for solving the technical problems of high threshold voltage, high driving level in saturation work and high driving power consumption of a SiC power MOSFET; the beneficial effects of reducing the threshold voltage and the driving voltage are achieved.

Example one

Referring to fig. 1 to 3, the present embodiment provides a tri-gate SiC lateral MOSFET power device, which includes

The SiC substrate is provided with a substrate groove;

the SiC epitaxial layer is internally provided with an epitaxial groove; the SiC epitaxial layer is arranged in the substrate groove;

the P-type well region is internally provided with a medium groove, and a channel region is arranged in the medium groove; the P-type well region is arranged in the epitaxial groove;

the grid electrode comprises two first side grid electrodes and a top grid electrode, two end parts of the top grid electrode are respectively connected to the side surface of one end part of the grid electrode to form an inverted U-shaped structure, the top grid electrode and the first side grid electrode except the top part and the connection part are all surrounded by a high-k medium, and the inverted U-shaped structure is arranged in the medium groove and protrudes out of the medium groove;

the source electrode is arranged in the medium groove and is arranged on one side of the U-shaped structure;

and the source electrode is arranged in the medium groove and is arranged on the other side of the U-shaped structure.

The grid further comprises at least one second side grid, the second side grids are uniformly arranged in the two side grids at intervals, one end of each second side grid is connected to the top grid, the second side grids are located outside the top grid connection position and are wrapped by the high-K medium, the second side grids are sequentially and progressively increased according to integer arrangement, the carrier density of a conducting channel is increased, and the on-resistance is reduced.

The thickness and the width of the first side gate and the second side gate are equal.

The longitudinal depth of the medium groove is smaller than that of the P-type well region.

The longitudinal depth of the first side gate is greater than or equal to the depth of the dielectric groove.

The method is used for SiC power devices and SiC power integrated circuits.

The threshold voltage is low because of the tri-gate structure, which has sufficient carriers to generate current at low gate voltages.

Due to the adoption of the tri-gate structure, the carrier concentration is saturated under the condition of lower gate voltage, and the specific on-resistance of the tri-gate structure is not reduced any more, so that the device can realize large current under the condition of lower gate driving voltage, and the driving power consumption is reduced.

Example two

As shown in fig. 4, on the basis of the first embodiment, a multi-gate structure, i.e., two first side gates and at least one second side gate, is adopted to further reduce the threshold voltage and improve the current carrying capability.

Although specific embodiments of the invention have been described above, 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 appended claims.