GaN HEMT devices with adjustable voltage field plates

Abstract

The application discloses a GaN HEMT device with a field plate with adjustable voltage. The GaN HEMT device comprises: a heterojunction, a dielectric layer and an insulating structure layer which are arranged in a stack, a two-dimensional electron gas is formed in the heterojunction, a source electrode, a drain electrode and a gate electrode which are arranged on the dielectric layer and are in contact with the heterojunction, the source electrode and the drain electrode can be connected through the two-dimensional electron gas, the source electrode and the drain electrode are respectively connected with a first electric connection structure and a second electric connection structure and are led out to the outside of the device through the first electric connection structure and the second electric connection structure, and a field plate which is at least partially arranged between the gate electrode and the drain electrode and is connected with a third electric connection structure and led out to the outside of the device through the third electric connection structure. The GaN HEMT device provided by the application can weaken the charge trap injection problem caused by uneven electric field distribution by adjusting the electric field, and further improves the device performance.

Description

Technical Field

[0001] This invention relates to a GaN HEMT device, and more particularly to a GaN HEMT device with an adjustable voltage field plate, belonging to the field of semiconductor technology. Background Technology

[0002] GaN HEMTs are heterojunction field-effect transistors designed for radio frequency power amplifiers. They feature a lateral channel structure, with the drain, source, and gate all located on the chip surface (which can be understood as a heterojunction field-effect transistor device). The source is typically connected to the bottom of the substrate and grounded via a metal via. GaN HEMTs utilize a two-dimensional electron gas generated between the AlGaN and GaN layers to create a conductive channel between the drain and source. The gate then controls the switching of this two-dimensional electron gas via voltage, amplifying the control signal.

[0003] Figure 1 The inventor of this invention provides a conventional GaN HEMT device structure, including a substrate 1 and a gallium nitride buffer layer 2, a gallium nitride intrinsic layer 3, and an aluminum gallium nitride layer 4 sequentially stacked on the substrate 1. A two-dimensional electron gas is formed between the aluminum gallium nitride layer 3 and the gallium nitride intrinsic layer 4. A silicon nitride layer 5 is also grown on the aluminum gallium nitride layer 4. A gate 11, a source 12, and a drain 13 are disposed on the silicon nitride layer 5. Etching windows are opened in the regions of the silicon nitride layer 5 corresponding to the gate 11, the source 12, and the drain 13. Parts of the gate 11, the source 12, and the drain 13 are disposed in the etching windows and form contact with the aluminum gallium nitride layer through the etching windows. The gate 11 and the drain 13 are also interconnected to the top layer through a metal layer 14. The source 12 is also connected to the back side of the substrate 1 through a conductive channel 16. A field plate 15 is located between the drain 13 and the gate 11 and is connected to the source 12 through a metal interconnect.

[0004] Traditional GaN HEMTs for radio frequency power amplifiers mainly employ source field plate technology, connecting the field plate to the source end and fixing it at zero potential. The surface potential is affected by setting different silicon nitride thicknesses. However, this brings several problems: 1) The surface potential is affected by changing the oxide layer thickness, and cannot be changed after manufacturing, requiring verification through fabrication experiments; 2) Fixing the field plate potential requires balancing the high-voltage reverse bias state and the conduction state, resulting in a sacrifice between high reliability and high performance. Summary of the Invention

[0005] The main objective of this invention is to provide a GaN HEMT device with an adjustable voltage field plate to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0007] This invention provides a GaN HEMT device with an adjustable voltage field plate, comprising:

[0008] A heterojunction, a dielectric layer, and an insulating structure layer are stacked sequentially, and a two-dimensional electron gas is formed within the heterojunction.

[0009] The device includes a source, a drain, and a gate, which are disposed on the dielectric layer and in contact with the heterojunction. The source and drain are connected via the two-dimensional electron gas. The source and drain are also connected to a first electrical connection structure and a second electrical connection structure, respectively, and are led out to the outside of the device via the first electrical connection structure and the second electrical connection structure, respectively.

[0010] A field plate, at least a portion of which is disposed between the gate and the drain, and the field plate is also connected to a third electrical connection structure and led out to the outside of the device via the third electrical connection structure.

[0011] Compared with the prior art, the advantages of the present invention include:

[0012] 1) The GaN HEMT device with an adjustable voltage field plate provided in this embodiment of the invention leads the field plate to the outside of the device through a circuit and forms an external port, thereby realizing the potential modulation of the field plate; and when the drain of the device is subjected to a large voltage, the potential of the field plate can be adjusted through the external port and the electric field on the surface of the device can be flattened, thereby reducing the gate electric field and enhancing the reliability and service life of the device without changing the device structure.

[0013] 2) The GaN HEMT device with an adjustable voltage field plate provided in this embodiment of the invention can raise the potential through the field plate when the device is fully turned on, thereby reducing the electric field in the lower region of the field plate, avoiding the problem of reduced two-dimensional electron gas caused by the field plate potential, and increasing the maximum current of the device.

[0014] 3) The GaN HEMT device with adjustable voltage field plate provided in this embodiment of the invention also reduces the charge trap injection problem caused by uneven electric field distribution by adjusting the electric field. Since the current collapse caused by gate trap charge will lead to an increase in on-resistance, this invention reduces the current collapse phenomenon and can improve the working efficiency of the device. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a conventional GaN HEMT device provided by the inventor of this case;

[0016] Figure 2 This is a GaN HEMT device with an adjustable voltage field plate provided in a typical embodiment of the present invention. Detailed Implementation

[0017] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0018] This invention provides a GaN HEMT device with an adjustable voltage field plate, which allows for flexible adjustment of the surface potential during use. This optimizes the electric field distribution without altering the device structure, maximizing device performance and effectively reducing time and experimental costs. Furthermore, during operation, an AC voltage can be applied to the field plate, allowing it to function differently depending on the operating state. For example, when the GaN HEMT is in a high-voltage, no-current state, the field plate potential primarily adjusts the surface electric field, making it more uniform. When the GaN HEMT is in a conducting state, the field plate potential primarily reduces surface depletion and lowers on-resistance.

[0019] This invention provides a GaN HEMT device with an adjustable voltage field plate, comprising:

[0020] A heterojunction, a dielectric layer, and an insulating structure layer are stacked sequentially, and a two-dimensional electron gas is formed within the heterojunction.

[0021] The device includes a source, a drain, and a gate, which are disposed on the dielectric layer and in contact with the heterojunction. The source and drain are connected via the two-dimensional electron gas. The source and drain are also connected to a first electrical connection structure and a second electrical connection structure, respectively, and are led out to the outside of the device via the first electrical connection structure and the second electrical connection structure, respectively.

[0022] A field plate, at least a portion of which is disposed between the gate and the drain, and the field plate is also connected to a third electrical connection structure and led out to the outside of the device via the third electrical connection structure.

[0023] Furthermore, the first electrical connection structure, the second electrical connection structure, and the third electrical connection structure are independently configured.

[0024] Furthermore, the first electrical connection structure extends from the first surface of the device and forms a first connection port on the first surface of the device, and the second electrical connection structure and the third electrical connection structure extend from the second surface of the device and form a second connection port and a third connection port on the second surface of the device, respectively, wherein the first surface and the second surface are arranged back to back.

[0025] Furthermore, the second electrical connection structure and the third electrical connection structure penetrate the insulating structure layer and are exposed from the surface of the insulating structure layer to form the second connection port and the third connection port, respectively.

[0026] Furthermore, the second electrical connection structure and the third electrical connection structure respectively include a first connecting metal and a second connecting metal.

[0027] Furthermore, the field plate includes a first portion and a second portion that are interconnected. The first portion is disposed on the dielectric layer and located between the gate and the drain, and the second portion is disposed above the gate and extends laterally in the direction toward the source.

[0028] Furthermore, the field plate has a single-layer or multi-layer structure.

[0029] Furthermore, the heterojunction is disposed on a buffer layer, the buffer layer is disposed on a substrate, and the second electrical connection structure penetrates the heterojunction, the buffer layer, and the substrate along the thickness direction and is exposed from the surface of the substrate.

[0030] Furthermore, the second electrical connection structure includes a conductive channel or a second connecting metal.

[0031] In some more specific implementations, the GaN HEMT device includes:

[0032] A gallium nitride buffer layer, a gallium nitride intrinsic layer, an aluminum gallium nitride barrier layer, a silicon nitride dielectric layer, and an insulating structure layer are sequentially stacked on a substrate, and a two-dimensional electron gas is formed between the gallium nitride intrinsic layer and the aluminum gallium nitride barrier layer.

[0033] The system includes a source, a drain, and a gate, which are disposed on the silicon nitride dielectric layer. A portion of the source, drain, and gate penetrates the silicon nitride dielectric layer and contacts the aluminum gallium nitride (AGaN) barrier layer. The source and drain are also connected via the two-dimensional electron gas. Furthermore, the source and drain are respectively connected to a first electrical connection structure and a second electrical connection structure. The first electrical connection structure penetrates the AGaN barrier layer, the intrinsic gallium nitride layer, the buffer layer, and the substrate along the thickness direction and is exposed on the surface of the substrate to form a first connection port. The second electrical connection structure penetrates the insulating structure layer along the thickness direction and is exposed on the surface of the insulating structure to form a second connection port.

[0034] A field plate, a portion of which is disposed in the silicon nitride dielectric layer and located between the gate and the drain, and the remaining portion of which is disposed above the gate and extends laterally in the direction toward the source, the field plate is also connected to a third electrical connection structure, the third electrical connection structure penetrating the insulating structure layer in the thickness direction and exposed from the surface of the insulating structure layer to form a third connection port.

[0035] The following will further explain the technical solution, its implementation process and principle in conjunction with the accompanying drawings and specific embodiments. Unless otherwise specified, the fabrication process of the GaN HEMT device in the embodiments of the present invention can be known to those skilled in the art.

[0036] Example 1

[0037] Please see Figure 2 A GaN HEMT device with an adjustable voltage field plate, comprising:

[0038] A gallium nitride buffer layer 22, a gallium nitride intrinsic layer 23, an aluminum gallium nitride barrier layer 24, a silicon nitride dielectric layer 25, and an insulating structure layer 26 are sequentially stacked on a substrate 21, and a two-dimensional electron gas is formed between the gallium nitride intrinsic layer 23 and the aluminum gallium nitride barrier layer 24.

[0039] The system comprises a source electrode 32, a drain electrode 33, and a gate electrode 31, which are disposed on the silicon nitride dielectric layer 25. A portion of the source electrode 32, drain electrode 33, and gate electrode 31 penetrates the silicon nitride dielectric layer 25 and contacts the aluminum gallium nitride barrier layer 24. The source electrode 32 and drain electrode 33 are also connected via the two-dimensional electron gas. Furthermore, the source electrode 32 and drain electrode 33 are respectively connected to a first electrical connection structure 36 and a second electrical connection structure 34. The first electrical connection structure 36 penetrates the aluminum gallium nitride barrier layer 24, the gallium nitride intrinsic layer 23, the gallium nitride buffer layer 22, and the substrate 21 along the thickness direction and is exposed from the surface (which can be understood as the back side) of the substrate 21 to form a first connection port. The second electrical connection structure 34 penetrates the insulating structure layer 26 along the thickness direction and is exposed from the surface of the insulating structure layer 26 to form a second connection port.

[0040] A field plate 35 is partially disposed on the silicon nitride dielectric layer 25 and located between the gate 31 and the drain 33, and the remaining portion is disposed above the gate 31 and extends laterally in the direction toward the source 32. The field plate 35 is also connected to a third electrical connection structure 37, which penetrates the insulating structure layer 26 along the thickness direction and is exposed from the surface of the insulating structure layer 26 to form a third connection port.

[0041] Specifically, the first electrical connection structure 36, the second electrical connection structure 34, and the third electrical connection structure 37 are all independently configured, and the first connection port, the second connection port, and the third connection port are also independently configured. The first electrical connection structure can be a connecting metal or a conductive channel, and the second and third electrical connection structures can be connecting metals; of course, the third electrical connection structure can also be a connecting circuit, etc.

[0042] Specifically, the field plate 35 includes a first part and a second part that are interconnected. The first part is disposed on the silicon nitride dielectric layer 25 and located between the gate 31 and the drain 33. The second part is disposed above the gate 31 and extends laterally in the direction toward the source 32. The second part of the field plate 35 is connected to a third electrical connection structure and leads out through the third electrical connection structure to form an independent connection port. The output characteristics of the field plate are affected by the potential of the field plate. The potential of the field plate 35 can be modulated by the third connection port disposed outside the device. It should be noted that the field plate 35 can be a single-layer or multi-layer structure.

[0043] Specifically, the silicon nitride dielectric layer 25 has etching windows in the electrode regions corresponding to the source 32, drain 33 and gate 31. Parts of the source 32, drain 33 and gate 31 are disposed within the etching windows and pass through the etching windows to contact the aluminum gallium nitride barrier layer 24.

[0044] Specifically, the substrate 21 can be made of monocrystalline silicon, silicon carbide, or sapphire, etc.

[0045] Comparative Example 1

[0046] Please see Figure 1 A GaN HEMT device includes a substrate 1 and a gallium nitride buffer layer 2, a gallium nitride intrinsic layer 3, and an aluminum gallium nitride layer 4 sequentially stacked on the substrate 1. A two-dimensional electron gas is formed between the aluminum gallium nitride layer 3 and the gallium nitride intrinsic layer 4.

[0047] A silicon nitride layer 5 is also grown on the aluminum gallium nitride layer 4. A gate 11, a source 12, and a drain 13 are disposed on the silicon nitride layer 5. Etching windows are opened in the areas of the silicon nitride layer 5 corresponding to the gate 11, the source 12, and the drain 13. Parts of the gate 11, the source 12, and the drain 13 are disposed in the etching windows and form contact with the aluminum gallium nitride layer through the etching windows. The gate 11 and the drain 13 are also interconnected to the top layer through the metal layer 14. The source 12 is also connected to the back side of the substrate 1 through the conductive channel 16. The field plate 15 is located between the drain 13 and the gate 11 and is connected to the source 12 through the metal interconnect.

[0048] This invention provides a GaN HEMT device with an adjustable voltage field plate. The field plate is led out to the outside of the device through a circuit to form an external port, thereby realizing the potential modulation of the field plate. When the drain of the device is subjected to a large voltage, the potential of the field plate can be adjusted through the external port and the electric field on the surface of the device can be flattened. This reduces the gate electric field without changing the device structure, thereby enhancing the reliability and service life of the device.

[0049] This invention provides a GaN HEMT device with an adjustable voltage field plate. When the device is fully turned on, the potential of the field plate can be raised, thereby reducing the electric field in the region below the field plate. This reduces the potential difference between the field plate and the two-dimensional electron gas below the field plate, thus avoiding the problem of reduced two-dimensional electron gas caused by the field plate potential and increasing the maximum current of the device. Furthermore, when the drain voltage is high, this GaN HEMT device with an adjustable voltage field plate can also reduce the potential of the field plate structure by adjusting the electric field, which can share part of the gate electric field. This weakens the charge trap injection problem caused by uneven electric field distribution and further improves device performance.

[0050] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A GaN HEMT device with an adjustable voltage field plate, characterized in that... include: A heterojunction, a dielectric layer, and an insulating structure layer are stacked sequentially, and a two-dimensional electron gas is formed within the heterojunction. The device includes a source, a drain, and a gate, which are disposed on the dielectric layer and contact the heterojunction through an etched window on the dielectric layer. The source and drain are connected by the two-dimensional electron gas. The source and drain are also connected to a first electrical connection structure and a second electrical connection structure, respectively, and are led out to the outside of the device through the first electrical connection structure and the second electrical connection structure, respectively. A field plate, at least a portion of which is disposed between the gate and the drain, and the field plate is also connected to a third electrical connection structure and led out to the outside of the device via the third electrical connection structure; The first electrical connection structure extends from the first surface of the device and forms a first connection port on the first surface. The second and third electrical connection structures extend from the second surface of the device and form a second connection port and a third connection port on the second surface, respectively. The first and second surfaces are arranged back-to-back. The first, second, and third electrical connection structures are independently arranged. The second and third electrical connection structures penetrate the insulating layer and are exposed on the surface of the insulating layer to form the second and third connection ports, respectively. The second and third electrical connection structures each include a first connection metal and a second connection metal. The field plate includes a first part and a second part that are interconnected. The first part is disposed on the dielectric layer and located between the gate and the drain. The second part is disposed above the gate and extends laterally in the direction toward the source. The third electrical connection structure is used to connect an AC voltage to adjust the potential of the field plate according to different operating states of the GaN HEMT device.

2. The GaN HEMT device according to claim 1, characterized in that: The field plate has a single-layer or multi-layer structure.

3. The GaN HEMT device according to claim 1, characterized in that: The heterojunction is disposed on the buffer layer, the buffer layer is disposed on the substrate, and the second electrical connection structure penetrates the heterojunction, the buffer layer, and the substrate along the thickness direction and is exposed from the surface of the substrate.

4. The GaN HEMT device according to claim 3, characterized in that: The second electrical connection structure includes a conductive channel.

5. The GaN HEMT device according to claim 1, characterized in that... include: A gallium nitride buffer layer, a gallium nitride intrinsic layer, an aluminum gallium nitride barrier layer, a silicon nitride dielectric layer, and an insulating structure layer are sequentially stacked on a substrate, and a two-dimensional electron gas is formed between the gallium nitride intrinsic layer and the aluminum gallium nitride barrier layer. The system includes a source, a drain, and a gate, which are disposed on the silicon nitride dielectric layer. A portion of the source, drain, and gate penetrates the silicon nitride dielectric layer and contacts the aluminum gallium nitride (AGaN) barrier layer. The source and drain are also connected via the two-dimensional electron gas. Furthermore, the source and drain are respectively connected to a first electrical connection structure and a second electrical connection structure. The first electrical connection structure penetrates the AGaN barrier layer, the intrinsic gallium nitride layer, the buffer layer, and the substrate along the thickness direction and is exposed on the surface of the substrate to form a first connection port. The second electrical connection structure penetrates the insulating structure layer along the thickness direction and is exposed on the surface of the insulating structure to form a second connection port. A field plate, a portion of which is disposed in the silicon nitride dielectric layer and located between the gate and the drain, and the remaining portion of which is disposed above the gate and extends laterally in the direction toward the source, the field plate is also connected to a third electrical connection structure, the third electrical connection structure penetrating the insulating structure layer in the thickness direction and exposed from the surface of the insulating structure layer to form a third connection port.

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