A GaN HEMT structure with active clamped absorption circuit

Abstract

This invention relates to the field of semiconductor technology and discloses a GaN HEMT structure with an active clamping absorption circuit. The GaN HEMT structure includes a base substrate, a base buffer layer, a base GaN layer, and a base AlGaN layer. The GaN HEMT structure also includes a base source, a drain metal, a base gate, a base dielectric layer, and a connection dielectric layer. This invention efficiently integrates the active clamping absorption component with the core structure of the GaN HEMT, optimizes the potential conduction path, and can quickly respond to the instantaneous overvoltage spikes generated at the drain in high-frequency switching scenarios. It efficiently absorbs and dissipates overvoltage energy, avoids overvoltage breakdown of the gate or drain insulation structure, significantly improves the operating stability of the device, and solves the core problem of traditional devices being easily damaged by overvoltage.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a GaN HEMT structure with an active clamping absorption circuit. Background Technology

[0002] With the rapid development of new energy vehicles, 5G communications, smart grids, and other fields towards higher frequencies, smaller sizes, and higher efficiency, stringent requirements are being placed on the performance of power semiconductor devices. GaN HEMTs (Gallium Nitride High Electron Mobility Transistors), with their wide bandgap, high breakdown electric field, and high electron mobility, have become core devices for replacing traditional silicon-based devices and improving the performance of power electronic systems. However, in high-frequency switching mode, GaN HEMTs are prone to transient overvoltage spikes at the drain. These spikes originate from the resonance between the device's parasitic capacitance and the circuit's parasitic inductance, which not only reduces the device's operational stability but may also break down the gate or drain insulation structure, leading to permanent device damage.

[0003] Existing patents disclose related GaN HEMT clamping protection technologies, such as the Chinese invention patent CN118588739A, "A p-GaN HEMT Structure with Clamping Diode." This patent introduces a p-GaN HEMT diode structure with a gate-drain short circuit on one side of a traditional p-GaN HEMT, connecting the P-GaN layer in the main power transistor region to ground, eliminating the negative charge stored in the P-GaN layer, and mitigating the threshold voltage drift caused by drain stress. However, this technology focuses on improving threshold voltage stability and does not design a protection mechanism for transient overvoltage spikes generated at the drain in high-frequency switching scenarios. Furthermore, its clamping diode can only passively discharge local charges, failing to achieve efficient absorption and rapid discharge of overvoltage energy, resulting in weak overvoltage suppression and slow response speed, making it difficult to adapt to the high-frequency, high-voltage application requirements in fields such as new energy and 5G. In addition, traditional active clamping structures generally suffer from low component integration and unstable potential conduction, failing to fully leverage the performance advantages of GaN devices.

[0004] This invention addresses the shortcomings of existing technologies by proposing a GaN HEMT structure with an active clamping absorption circuit. By efficiently integrating the active clamping absorption component with the core structure of the GaN HEMT, the potential conduction path is optimized, the overvoltage suppression response speed and energy absorption efficiency are improved, and the stability of the device's switching characteristics is ensured. This solves the overvoltage damage problem of GaN HEMTs during high-frequency operation, thereby improving the reliability of power electronic systems and meeting the high-performance application requirements of new energy, 5G and other fields. Summary of the Invention

[0005] This invention provides a GaN HEMT structure with an active clamping absorption circuit to solve existing technical problems. It solves the core problem that GaN HEMTs are prone to instantaneous overvoltage spikes at the drain in high-frequency switching mode, which leads to reduced device stability or even permanent damage.

[0006] To solve the above-mentioned technical problems, according to one aspect of the present invention, more specifically, a GaN HEMT structure with an active clamping absorption circuit, comprising a GaN HEMT structure, characterized in that: the GaN HEMT structure comprises a base substrate, a base buffer layer, a base GaN layer, and a base AlGaN layer;

[0007] The GaN HEMT structure further includes: a base source, a drain metal, a base gate, a base dielectric layer, and a connection dielectric layer.

[0008] Furthermore, the base source and the drain metal are located on the left and right sides of the top of the base AlGaN layer, respectively, and the base gate is located between the base source and the drain metal.

[0009] Furthermore, the base gate is located near the base source, and the distance between the base gate and the base source is 0.5-1µm;

[0010] A base dielectric layer is filled between the base source and the base gate, and between the drain metal and the base gate.

[0011] Furthermore, a connecting dielectric layer is provided on the right side of the base GaN layer and the base AlGaN layer, and the connecting dielectric layer is in contact with the left side of the drain metal.

[0012] Furthermore, a capacitor is provided on the right side of the upper surface of the drain metal, a grounding layer is fixedly connected to the upper surface of the capacitor, and a silver electrode is provided on the left side of the lower surface of the grounding layer.

[0013] Furthermore, a tantalum oxide layer is disposed on the lower surface of the silver electrode, and the lower surface of the tantalum oxide layer is in contact with the upper surface of the drain metal.

[0014] Furthermore, the GaN HEMT structure also includes an under-substrate P-GaN layer, which is located below the base gate.

[0015] The present invention provides a GaN HEMT structure with an active clamp absorption circuit. Compared with the prior art, the advantages achieved by this method are as follows:

[0016] 1. This invention efficiently integrates the active clamping absorption component with the core structure of GaN HEMT, optimizes the potential conduction path, and can quickly respond to the instantaneous overvoltage spike generated by the drain in high-frequency switching scenarios. It efficiently absorbs and dissipates overvoltage energy, avoids overvoltage breakdown of the gate or drain insulation structure, significantly improves the operating stability of the device, and solves the core problem that traditional devices are easily damaged by overvoltage.

[0017] 2. This invention constructs a collaborative discharge architecture through capacitors, grounding layer, silver electrode and tantalum oxide layer. Compared with existing clamping protection technology, it specifically strengthens the overvoltage spike protection mechanism, improves overvoltage suppression capability and response speed, effectively makes up for the defects of passive discharge and insufficient protection in existing technology, and is suitable for the needs of high frequency and high voltage application scenarios.

[0018] 3. This invention, through integrated design, abandons the discrete component combination mode of traditional active clamping structure, improves component integration and potential conduction stability, reduces signal transmission loss, and fully leverages the performance advantages of GaN devices' wide bandgap and high mobility, thus helping power electronic systems achieve high-frequency and miniaturized upgrades.

[0019] 4. This invention, through the synergistic effect of the P-GaN layer under the substrate and the active clamping absorption circuit, enhances the gate's control over the two-dimensional electron gas while ensuring overvoltage protection, improves the device's switching characteristics and threshold voltage stability, and balances device performance and reliability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0022] In the figure: 101, base substrate; 102, base buffer layer; 103, base GaN layer; 104, base AlGaN layer; 105, base source; 106, drain metal; 107, base gate; 108, base dielectric layer; 109, under-base P-GaN layer; 110, interconnect dielectric layer; 201, capacitor; 202, ground layer; 203, silver electrode; 204, tantalum oxide layer. Detailed Implementation

[0023] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] like Figure 1As shown, according to one aspect of the present invention, during the conduction and current-carrying operation phases of a GaN HEMT core device, each base layer component collaboratively constructs a stable current-carrying channel and ensures structural insulation and support. As the fundamental load-bearing component of the entire structure, the base substrate 101 provides stable physical support and structural reliance for all functional layers above it. The base buffer layer 102 above it isolates substrate defects and optimizes lattice matching, preventing defects in the substrate from diffusing to the upper functional layers and affecting device performance. The base GaN layer 103 above the base buffer layer 102 and the base AlGaN layer 104 form a heterojunction structure. A high-mobility two-dimensional electron gas is induced at their interface, which is the core current-carrying channel for achieving low on-resistance and high switching speed in GaN HEMT devices. When a forward driving voltage is applied to the base gate 107, since the base gate 107 is close to the base source 105 and the distance between the two is controlled within a reasonable range of 0.5-1µm, the gate electric field can efficiently regulate the two-dimensional electron gas distribution on the surface of the base AlGaN layer 104, thereby opening the current-carrying channel between the source and drain. At this time, the base source 105 acts as the carrier injection terminal, injecting electrons into the two-dimensional electron gas channel. The electrons migrate along the heterojunction interface channel formed by the base GaN layer 103 and the base AlGaN layer 104 to the drain metal 106. The drain metal 106 then completes the collection and output of carriers, realizing the conduction of the device. In this process, the base dielectric layer 108, which fills the space between the base source 105 and the base gate 107, and between the drain metal 106 and the base gate 107, plays a key insulating role, preventing short circuits between the source, drain, and gate, and ensuring the stability of the gate drive signal. The connecting dielectric layer 110, which is located on the right side of the base GaN layer 103 and the base AlGaN layer 104 and is in contact with the left side of the drain metal 106, further fixes the position of the drain metal 106 and isolates the drain metal 106 from the lower functional layer, preventing the drain potential from interfering with the lower heterojunction structure.

[0026] When an overvoltage surge occurs in the circuit, the components of the active clamping absorption circuit activate and work together to suppress overvoltage and absorb energy, ensuring the safety of the core GaN HEMT device. When the drain metal 106 experiences a sharp rise in potential due to an overvoltage surge, the capacitor 201 located on its upper right side responds first, utilizing the energy storage characteristics of the capacitor to quickly absorb the instantaneous energy generated by the overvoltage, initially suppressing the surge in drain potential. The ground layer 202, fixedly connected to the upper surface of the capacitor 201, serves as a critical path for energy dissipation, guiding the energy absorbed by the capacitor to the ground terminal through its own conductivity. Meanwhile, the silver electrode 203 located on the lower left side of the ground layer 202 plays a role in potential conduction and contact enhancement, stably transmitting the potential signal of the ground layer 202 to the tantalum oxide layer 204 below. The tantalum oxide layer 204 on the lower surface of the silver electrode 203 has both insulating and dielectric properties. On the one hand, it isolates the silver electrode 203 from the drain metal 106, preventing direct contact that could cause a short circuit. On the other hand, its dielectric properties optimize potential transfer efficiency, ensuring that the overvoltage signal from the drain metal 106 can accurately trigger the discharge action of the ground layer 202. During this process, the close contact between the tantalum oxide layer 204 and the upper surface of the drain metal 106 ensures the continuity of potential transfer, while the stable connection between the capacitor 201 and the drain metal 106 ensures the efficient capture of overvoltage energy. Finally, through the complete path of "capacitor energy storage - silver electrode conduction - ground layer discharge", the excess energy generated by the overvoltage is safely released, causing the potential of the drain metal 106 to quickly fall back to a safe range. This protects core components such as the base source 105, base gate 107, base GaN layer 103, and base AlGaN layer 104 from overvoltage damage, ensuring the stable and reliable operation of the entire GaN HEMT structure.

[0027] Example 2

[0028] like Figure 2As shown in this embodiment, during the conduction and current-carrying operation phases of the GaN HEMT core device, the various base components work together to construct a stable current-carrying channel and ensure structural insulation and support. As the fundamental supporting component of the entire structure, the base substrate 101 provides stable physical support and structural reliance for all functional layers above it. The base buffer layer 102 above it isolates substrate defects and optimizes lattice matching, preventing defects in the substrate from diffusing to the upper functional layers and affecting device performance. The base GaN layer 103 above the base buffer layer 102 and the base AlGaN layer 104 form a heterojunction structure. A high-mobility two-dimensional electron gas is induced at their interface, which is the core current-carrying channel for achieving low on-resistance and high switching speed in GaN HEMT devices. The base-below P-GaN layer 109, located below the base gate 107, can enhance the gate's control over the two-dimensional electron gas through hole injection and electric field modulation, improving the device's switching characteristics and threshold voltage stability. When a forward driving voltage is applied to the base gate 107, combined with the modulation effect of the P-GaN layer 109 under the base, and the fact that the base gate 107 is close to the base source 105 and the distance between the two is controlled within a reasonable range of 0.5-1µm, the gate electric field can efficiently regulate the two-dimensional electron gas distribution on the surface of the base AlGaN layer 104, thereby opening the current-carrying channel between the source and drain. At this time, the base source 105 acts as the carrier injection terminal, injecting electrons into the two-dimensional electron gas channel. The electrons migrate along the heterojunction interface channel formed by the base GaN layer 103 and the base AlGaN layer 104 to the drain metal 106. The drain metal 106 then completes the collection and output of carriers, realizing the conduction and current carrying of the device. In this process, the base dielectric layer 108, which fills the space between the base source 105 and the base gate 107, and between the drain metal 106 and the base gate 107, plays a key insulating role, preventing short circuits between the source, drain, and gate, and ensuring the stability of the gate drive signal. The connecting dielectric layer 110, which is located on the right side of the base GaN layer 103 and the base AlGaN layer 104 and is in contact with the left side of the drain metal 106, further fixes the position of the drain metal 106 and isolates the drain metal 106 from the lower functional layer, preventing the drain potential from interfering with the lower heterojunction structure.

[0029] When the drain metal 106 experiences a sharp rise in potential due to an overvoltage surge, the capacitor 201 positioned on its upper right side responds first, rapidly absorbing the instantaneous energy generated by the overvoltage using the capacitor's energy storage characteristics, thus initially suppressing the surge in drain potential. The grounding layer 202, fixedly connected to the upper surface of the capacitor 201, serves as a critical path for energy dissipation, guiding the energy absorbed by the capacitor to the ground terminal through its own conductivity. Meanwhile, the silver electrode 203 positioned on the lower left side of the grounding layer 202 acts as a potential conduction and contact enhancement agent, stably transmitting the potential signal from the grounding layer 202 to the tantalum oxide layer 204 below. The tantalum oxide layer 204 on the lower surface of the silver electrode 203 possesses both insulating and dielectric properties. On one hand, it isolates the silver electrode 203 from the drain metal 106, preventing direct contact and short circuits. On the other hand, its dielectric properties optimize potential transmission efficiency, ensuring that the overvoltage signal from the drain metal 106 accurately triggers the discharge action of the grounding layer 202. During this process, the close contact between the tantalum oxide layer 204 and the upper surface of the drain metal 106 ensures the continuity of potential transfer, while the stable connection between the capacitor 201 and the drain metal 106 ensures the efficient capture of overvoltage energy. Finally, through the complete path of "capacitor energy storage - silver electrode conduction - ground layer discharge", the excess energy generated by overvoltage is safely released, causing the potential of the drain metal 106 to quickly fall back to a safe range. This protects core components such as the base source 105, base gate 107, under-base P-GaN layer 109, base GaN layer 103, and base AlGaN layer 104 from overvoltage damage, ensuring the stable and reliable operation of the entire GaN HEMT structure.

[0030] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A GaN HEMT structure with active clamped absorption circuit comprising a GaN HEMT structure, characterized by: The GaN HEMT structure includes a base substrate (101), a base buffer layer (102), a base GaN layer (103), and a base AlGaN layer (104). The GaN HEMT structure further includes: a base source (105), a drain metal (106), a base gate (107), a base dielectric layer (108), and a connection dielectric layer (110). A capacitor (201) is provided on the right side of the upper surface of the drain metal (106). A ground layer (202) is fixedly connected to the upper surface of the capacitor (201). A silver electrode (203) is provided on the left side of the lower surface of the ground layer (202). A tantalum oxide layer (204) is provided on the lower surface of the silver electrode (203). The lower surface of the tantalum oxide layer (204) is in contact with the upper surface of the drain metal (106).

2. The GaN HEMT structure with an active-clamp absorption circuit according to claim 1, characterized in that: The base source electrode (105) and the drain metal (106) are located on the left and right sides of the top of the base AlGaN layer (104), respectively, and the base gate electrode (107) is located between the base source electrode (105) and the drain metal (106).

3. The GaN HEMT structure with an active-clamp absorptive circuit according to claim 1, characterized in that: The base gate (107) is located near the base source (105), and the distance between the base gate (107) and the base source (105) is 0.5-1 μm; A base dielectric layer (108) is filled between the base source (105) and the base gate (107), and between the drain metal (106) and the base gate (107).

4. The GaN HEMT structure with an active-clamp absorptive circuit of claim 1, wherein: A connecting dielectric layer (110) is provided on the right side of the base GaN layer (103) and the base AlGaN layer (104), and the connecting dielectric layer (110) is in contact with the left side of the drain metal (106).

5. The GaN HEMT structure with an active-clamp snubber circuit of claim 1, wherein: The GaN HEMT structure further includes a P-GaN layer (109) under the substrate, which is located below the substrate gate (107).

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