Semiconductor device and method of manufacturing the same

Abstract

A semiconductor device and a preparation method thereof, relating to the technical field of semiconductor. The device comprises a depletion mode HEMT device body and an ESD protection structure, the ESD protection structure comprises a diode group connected between the gate of the depletion mode HEMT device body and the source of the depletion mode HEMT device body, the diode group comprises a Schottky diode conducting from the source of the depletion mode HEMT device body to the gate of the depletion mode HEMT device body; the ESD protection structure is located below the gate pad of the depletion mode HEMT device body; and / or, the ESD protection structure is located below the thickened metal of the source of the depletion mode HEMT device body, and the orthographic projection of the ESD protection structure on the substrate of the depletion mode HEMT device body does not overlap with the orthographic projection of the active region of the depletion mode HEMT device body on the substrate. The device can improve the ESD protection level without occupying the effective chip area of the device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a semiconductor device and its fabrication method. Background Technology

[0002] GaN-based HEMT (High Electron Mobility Transistor) devices, as third-generation semiconductor devices, have higher frequencies, higher operating temperatures, higher breakdown voltages, and higher power, and have broad application prospects in military and civilian fields of high-frequency, high-voltage, high-temperature, and high-power devices.

[0003] GaN-based HEMT power electronic devices are primarily enhancement-mode devices (threshold voltage Vth > 0V). This means that P-type GaN is retained under the gate to deplete the two-dimensional electron gas in the channel, resulting in the source and drain being off when the gate is unbiased or zero-biased. The device only turns on when a positive voltage (above the threshold voltage) is applied to the gate. Due to this characteristic of enhancement-mode GaN HEMT devices, the gate and drain can often be shorted to form a diode with rectification function.

[0004] However, GaN-based HEMT RF devices are typically depletion-mode devices (threshold voltage Vth < 0V), meaning that when no voltage is applied to the gate, the source and drain are in a conducting state; when a negative voltage (below the threshold voltage) is applied to the gate, the two-dimensional electron gas in the channel is depleted, putting the device in a turn-off state. Based on this characteristic of depletion-mode GaN HEMT devices, it is impossible to transplant the ESD protection structure of GaN-based HEMT power electronic devices into depletion-mode GaN-based HEMT RF devices. Therefore, how to achieve ESD protection in depletion-mode GaN-based HEMT RF devices has become a pressing technical challenge. Summary of the Invention

[0005] The purpose of this invention is to provide a semiconductor device and its fabrication method, which can set an ESD protection structure on the front side of a depletion-type GaN-based HEMT radio frequency device, thereby improving the device's ESD protection capability.

[0006] The embodiments of the present invention are implemented as follows:

[0007] In one aspect, the present invention provides a semiconductor device comprising a depletion-mode HEMT device body and an ESD protection structure. The ESD protection structure includes a diode group connected between a gate pad and a source of the depletion-mode HEMT device body, the diode group comprising Schottky diodes; the Schottky diodes are conductive from the source of the depletion-mode HEMT device body toward the gate pad; and the ESD protection structure is located below the gate pad of the depletion-mode HEMT device body; and / or, the ESD protection structure is located below the source thickened metal of the depletion-mode HEMT device body, and the orthographic projection of the ESD protection structure on the substrate of the depletion-mode HEMT device body does not overlap with the orthographic projection of the active region of the depletion-mode HEMT device body on the substrate. This semiconductor device enables the ESD protection structure to be disposed on the front side of a depletion-mode GaN-based HEMT RF device, thereby improving the device's ESD protection capability.

[0008] Optionally, the gate voltage operating range of the depletion-mode HEMT device body is in the range of -V. min To V max The ESD protection structure consists of N diode groups connected in series, with each diode group having a turn-on voltage of V. f Then N×V f >V min .

[0009] Optionally, when the ESD protection structure is located below the gate pad of the depletion-type HEMT device body, the electrostatic discharge protection level of the ESD protection structure is V. ESD V ESD The corresponding current value is I max The diode group consists of M Schottky diodes connected in parallel, and the current density per unit gate width of the Schottky diodes is J. SBD The gate width of a Schottky diode is W. g Then M×J SBD ×W g >I max .

[0010] Optionally, the ratio of the gate length of the depletion-type HEMT device body to the anode length of the Schottky diode is between 1:2 and 1:10, and the anode length of the Schottky diode is the length of the anode of the Schottky diode along the anode and cathode arrangement direction of the Schottky diode.

[0011] Optionally, the Schottky diodes in the diode group are connected in parallel along a first direction, and the diode group is connected in series along a second direction. The length of the gate pad of the depletion-type HEMT device body along the first direction is L, and the length of the Schottky diode along the first direction is L1, and L / L1>M. The first direction is the arrangement direction of the gate pad and the drain pad of the depletion-type HEMT device body, and the second direction is the arrangement direction of the source and the drain of the depletion-type HEMT device body.

[0012] Optionally, the length of the gate pad of the depletion-type HEMT device body along the second direction is l, the length of the Schottky diode along the second direction is l1, and l / l1 > N.

[0013] Optionally, the diode group is connected in parallel along the third direction, and the Schottky diodes are connected in series along the third direction; the length of the gate pad of the depletion-type HEMT device body along the third direction is R, the length of the Schottky diode along the third direction is R1, and R / R1 > M×N; the third direction is the arrangement direction of the source and drain of the depletion-type HEMT device body.

[0014] Optionally, the length of the gate pad of the depletion-type HEMT device body along the fourth direction is r, and the length of the Schottky diode along the fourth direction is r1; then r / r1>1, and the fourth direction is the arrangement direction of the gate pad and the drain pad of the depletion-type HEMT device body.

[0015] Optionally, when the ESD protection structure is located below the source thickened metal of the depletion-type HEMT device body, and the orthographic projection of the ESD protection structure on the substrate of the depletion-type HEMT device body does not overlap with the orthographic projection of the active region of the depletion-type HEMT device body on the substrate; the electrostatic discharge protection level of the ESD protection structure is V. ESD V ESD The corresponding current value is I max The diode group consists of M Schottky diodes connected in parallel. The depletion-mode HEMT device body includes Q source-thickened metal elements. The current density per unit gate width of the Schottky diode is J. SBD The gate width of a Schottky diode is W. g Then M×Q×J SBD ×W g >I max .

[0016] In another aspect, the present invention provides a method for fabricating a semiconductor device, the method comprising: forming an epitaxial structure on a substrate, the epitaxial structure including an active region and a passive region located outside the active region; depositing a metal material on the epitaxial structure to form a source and a drain of a depletion-type HEMT device body spaced apart in the active region, and forming a first electrode of a diode group in the passive region to obtain a first device; forming a first passivation layer covering the passive region and the active region on the first device; forming a first window exposing the passive region of the epitaxial structure and a first etching window of the epitaxial structure located between the source and drain of the depletion-type HEMT device body and exposing the active region on the first passivation layer, and depositing metal material in the first window and the first etching window to form a second electrode of the diode group and a gate of the depletion-type HEMT device body, respectively, to obtain a second device, wherein the depletion-type HEMT device... The source of the T device body is interconnected with the second electrode of the diode group; a second passivation layer covering the passive region and the active region is formed on the second device; a second window exposing the first electrode of the diode group, a second etching window exposing the source of the depletion-type HEMT device body, and a third etching window exposing the drain of the depletion-type HEMT device body are formed on the second passivation layer; a source thickening metal and a drain thickening metal are formed on the source and drain of the depletion-type HEMT device body, respectively; and drain pads interconnected with the drain thickening metal of the depletion-type HEMT device body and gate pads interconnected with the gate of the depletion-type HEMT device body are formed in the passive region, respectively. The gate pads are interconnected with the first electrode of the diode group through the second window. The diode group is connected between the source of the depletion-type HEMT device body and the gate pad of the depletion-type HEMT device body to form an ESD protection structure, and the diode group includes Schottky diodes.

[0017] The beneficial effects of this invention include:

[0018] The semiconductor device provided in this application includes a depletion-mode HEMT device body and an ESD protection structure. The ESD protection structure includes a diode group connected between the gate pad and the source of the depletion-mode HEMT device body. The diode group includes Schottky diodes. The Schottky diodes are conductive from the source of the depletion-mode HEMT device body towards the gate pad. The ESD protection structure is located below the gate pad of the depletion-mode HEMT device body. And / or, the ESD protection structure is located below the source thickened metal of the depletion-mode HEMT device body, and the orthographic projection of the ESD protection structure on the substrate of the depletion-mode HEMT device body does not overlap with the orthographic projection of the active region of the depletion-mode HEMT device body on the substrate. This application connects a certain number of diode groups between the gate pad and the source of the depletion-mode HEMT device body, with each diode group including a certain number of Schottky diodes. This forms an ESD protection structure between the gate and source of the depletion-mode HEMT device body, thereby improving the ESD capability of the depletion-mode GaN RF device. Furthermore, this application positions the ESD protection structure below the gate pad and / or source thickened metal of the depletion-mode HEMT device body. This allows for maximizing the area of ​​the Schottky diodes without occupying the effective chip area of ​​the semiconductor device, thus improving the ESD protection level. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is one of the schematic diagrams of the structure of a semiconductor device provided in an embodiment of the present invention;

[0021] Figure 2 This is a second schematic diagram of the structure of a semiconductor device provided in an embodiment of the present invention;

[0022] Figure 3 for Figure 2 Equivalent circuit diagram of the ESD protection structure in China;

[0023] Figure 4 This is the third schematic diagram of the structure of a semiconductor device provided in an embodiment of the present invention;

[0024] Figure 5 for Figure 4Equivalent circuit diagram of the ESD protection structure in China;

[0025] Figure 6 This is the fourth schematic diagram of the structure of a semiconductor device provided in an embodiment of the present invention;

[0026] Figure 7 This is a schematic flowchart of a method for fabricating a semiconductor device according to an embodiment of the present invention;

[0027] Figure 8 One of the schematic diagrams illustrating the fabrication process of a semiconductor device provided in an embodiment of the present invention;

[0028] Figure 9 This is a second schematic diagram illustrating the fabrication process of a semiconductor device provided in an embodiment of the present invention.

[0029] Figure 10 The third schematic diagram of the semiconductor device fabrication process provided in the embodiments of the present invention;

[0030] Figure 11 Fourth schematic diagram of the semiconductor device fabrication process provided in the embodiments of the present invention;

[0031] Figure 12 Fifth schematic diagram of the semiconductor device fabrication process provided in the embodiments of the present invention;

[0032] Figure 13 Fifth schematic diagram of the structure of a semiconductor device provided in the embodiments of the present invention;

[0033] Figure 14 for Figure 13 A magnified view of a section at point A in the middle;

[0034] Figure 15 for Figure 14 Equivalent circuit diagram of the ESD protection structure in China.

[0035] Icons: 11-Gate of depletion-type HEMT device body; 12-Source of depletion-type HEMT device body; 13-Drain of depletion-type HEMT device body; 14-Gate pad; 15-Drain pad; 16-Substrate; 17-Epitaxial structure; 20-ESD protection structure; 21-Diode group; 211-Schottky diode; a-First direction; b-Second direction; c-Third direction; d-Fourth direction; 31-First electrode; 32-First passivation layer; 33-Second electrode; 34-Second passivation layer; e-Sixth direction; f-Fifth direction. Detailed Implementation

[0036] The embodiments described below represent the information necessary for those skilled in the art to practice the embodiments and illustrate the best mode for practicing the embodiments. After reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of the invention and will recognize the applications of these concepts not specifically set forth herein. It should be understood that these concepts and applications fall within the scope of the invention and the appended claims. It should be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element without departing from the scope of the invention, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] It should be understood that when an element (such as a layer, region, or substrate) is referred to as "on another element" or "extending to another element," it may be directly on or directly extended to the other element, or there may be an intermediate element. Conversely, when an element is referred to as "directly on another element" or "directly extending to another element," there is no intermediate element. Similarly, it should be understood that when an element (such as a layer, region, or substrate) is referred to as "above another element" or "extending above another element," it may be directly on or directly extended to the other element, or there may be an intermediate element. Conversely, when an element is referred to as "directly on another element" or "extending directly to another element," there is no intermediate element. It should also be understood that when an element is referred to as "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be an intermediate element. Conversely, when an element is referred to as "directly connected" or "directly coupled" to another element, there is no intermediate element.

[0038] Related terms such as “below”, “above”, “upper”, “lower”, “horizontal”, or “vertical” are used herein to describe the relationship of one element, layer, or region to another, as illustrated in the figures. It should be understood that these terms, and those discussed above, are intended to cover different orientations of the device other than those depicted in the figures.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “described” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that, when used herein, the term “comprising” indicates the presence of said features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups of the foregoing. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that the terms used herein should be interpreted as having the meaning consistent with their meaning in the context of this specification and related fields, and should not be interpreted in an idealized or overly formal sense, unless explicitly defined herein.

[0040] Please refer to Figures 1 to 3 This embodiment provides a semiconductor device including a depletion-mode HEMT device body and an ESD protection structure 20. The ESD protection structure 20 includes a diode group 21 connected between the gate pad 14 and the source 12 of the depletion-mode HEMT device body. The diode group 21 includes a Schottky diode 211. The Schottky diode 211 is conductive from the source 12 of the depletion-mode HEMT device body towards the gate pad 14 of the depletion-mode HEMT device body. The ESD protection structure 20 is located below the gate pad 14 of the depletion-mode HEMT device body. And / or, the ESD protection structure 20 is located below the source thickened metal of the depletion-mode HEMT device body, and the orthographic projection of the ESD protection structure 20 on the substrate 16 of the depletion-mode HEMT device body does not overlap with the orthographic projection of the active region of the depletion-mode HEMT device body on the substrate 16.

[0041] Please refer to Figure 1 and Figure 2 The depletion-type HEMT device body includes a gate 11, a source 12, a drain 13, a gate pad 14, and a drain pad 15. This depletion-type HEMT device body is a typical depletion-type transistor, and its specific structure and function are well known to those skilled in the art, so they will not be described in detail here. The main purpose of this application is to integrate an ESD protection structure 20 on the depletion-type HEMT device body, thereby setting an ESD protection structure 20 on the front side of the depletion-type GaN-based HEMT RF device, improving the device's ESD protection capability, and thus compensating for the lack of an ESD protection structure 20 in existing depletion-type RF devices.

[0042] The aforementioned ESD protection structure 20 includes a diode group 21 connected between the gate pad 14 and the source 12 of the depletion-type HEMT device body. When the diode group 21 includes two or more diodes, each diode group 21 is connected in series between the gate pad 14 and the source 12 of the depletion-type HEMT device body. When the diode group 21 includes two or more Schottky diodes 211, each Schottky diode 211 is connected in parallel.

[0043] like Figure 1 As shown, Figure 1 This example illustrates that diode group 21 comprises two diodes, and each diode group 21 comprises two Schottky diodes 211. Of course, the inclusion of two diode groups 21 and two Schottky diodes 211 in each diode group 21 is merely an example and not a specific limitation on the number of diode groups 21 or the number of Schottky diodes 211 in each diode group 21. For example, as... Figure 6 As shown, diode group 21 may also include three, and each diode group 21 may also include three Schottky diodes 211.

[0044] It should be noted that the specific number of diode groups 21 and the specific number of Schottky diodes 211 in each diode group 21 can be determined by those skilled in the art according to the ESD protection level requirements; this application does not impose specific limitations. For example, such as Figure 2 and Figure 3 As shown, diode group 21 may include two, and each diode group 21 may include two Schottky diodes 211 connected in parallel; for example, as Figure 4 , Figure 5 and Figure 6 As shown, diode group 21 may also include three, and each diode group 21 may include three Schottky diodes 211 connected in parallel.

[0045] Due to the limitations of the Schottky diode 211's own current-carrying capacity, the area of ​​the Schottky diode 211 needs to be made sufficiently large in order for the ESD protection structure 20 to achieve a certain ESD protection level. However, increasing the area of ​​the Schottky diode 211 will undoubtedly put significant pressure on the chip area and cost of semiconductor devices. To solve this problem, this application now provides the following three methods for the placement of the ESD protection structure 20:

[0046] In a first feasible embodiment, the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body.

[0047] In another feasible embodiment, the ESD protection structure 20 is located below the source thickened metal of the depletion-type HEMT device body, and the orthographic projection of the ESD protection structure 20 on the substrate 16 of the depletion-type HEMT device body does not overlap with the orthographic projection of the active region of the depletion-type HEMT device body on the substrate 16.

[0048] In another feasible embodiment, the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body and the source thickened metal of the depletion-type HEMT device body. That is, a portion of the Schottky diode 211 in the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body, and another portion of the Schottky diode 211 is located below the source thickened metal of the depletion-type HEMT device body. It should be understood that the portion of the ESD protection structure 20 located below the source thickened metal of the depletion-type HEMT device body should have non-overlapping active regions.

[0049] Since the gate pad 14 and source 12 of the depletion-type HEMT device body have large areas, the above configuration can maximize the area of ​​the Schottky diode 211 without the ESD protection structure occupying the effective chip area of ​​the semiconductor device, thereby improving the protection level.

[0050] In summary, the semiconductor device provided in this application includes a depletion-mode HEMT device body and an ESD protection structure 20. The ESD protection structure 20 includes a diode group 21 connected between the gate pad 14 and the source 12 of the depletion-mode HEMT device body. The diode group 21 includes a Schottky diode 211. The Schottky diode 211 is conductive from the source 12 of the depletion-mode HEMT device body towards the gate pad 14 of the depletion-mode HEMT device body. The ESD protection structure 20 is located below the gate pad 14 of the depletion-mode HEMT device body. And / or, the ESD protection structure 20 is located below the source thickened metal of the depletion-mode HEMT device body, and the orthographic projection of the ESD protection structure 20 on the substrate 16 of the depletion-mode HEMT device body does not overlap with the orthographic projection of the active region of the depletion-mode HEMT device body on the substrate 16. This application constructs a diode group 21 between the gate pad 14 and the source 12 of a depletion-mode HEMT device, with each diode group 21 including a Schottky diode 211. This forms an ESD protection structure 20 between the gate 11 and the source 12 of the depletion-mode HEMT device. When the gate 11 of the depletion-mode HEMT device experiences a significant electrostatic discharge (ESD) shock, the ESD protection structure 20 creates an ESD leakage path, preventing destructive damage to the gate 11 and thus improving the ESD capability of the depletion-mode GaN RF device. Furthermore, this application positions the ESD protection structure 20 below the gate pad 14 and / or the thickened source metal of the depletion-mode HEMT device. This allows for maximizing the area of ​​the Schottky diode 211 without encroaching on the effective chip area of ​​the semiconductor device, thereby enhancing the ESD protection level.

[0051] In the first embodiment, when the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body, the ESD protection structure 20 should meet the following requirements:

[0052] Optionally, in this embodiment, the gate voltage operating range of the depletion-mode HEMT device body is in the range of -V. min To V max Between them, the ESD protection structure 20 includes N diode groups 21 connected in series, and the turn-on voltage of each diode group 21 is V. f Then N×V f >V minThis ensures that the operating voltage of the ESD protection structure 20 is less than any point within the gate voltage operating range of the depletion-type HEMT device. Consequently, the ESD protection structure 20 remains inactive while the depletion-type HEMT device is operating, thus preventing it from affecting the normal operation of the device.

[0053] For example, the gate voltage operating range of depletion-type HEMT devices is between -10V and 2V, and the turn-on voltage V of each diode group 21 is... f If the voltage is 2V, then the ESD protection structure 20 needs to include at least five diode groups 21 connected in series (i.e., N needs to be greater than or equal to 5). In this way, the ESD protection structure 20 will only turn on below -10V, thus preventing the ESD protection structure 20 from affecting the normal operation of the depletion-type HEMT device. It should be understood that the turn-on voltage V of each diode group 21 is... f The use of 2V is merely an example given in this application and should not be regarded as a limitation of this application.

[0054] In this embodiment, the electrostatic voltage protection level of the ESD protection structure 20 is V. ESD V ESD The corresponding current value is I max The diode group 21 includes M Schottky diodes 211 connected in parallel, and the current density per unit gate width of the Schottky diodes 211 is J. SBD The gate width of the Schottky diode 211 is W. g Then M×J SBD ×W g >I max .

[0055] It should be noted that, for a given ESD electrostatic discharge protection level V... ESD When this occurs, there must exist a maximum current value that allows the corresponding ESD protection structure 20 to conduct safely. This maximum current value is V. ESD Corresponding current value I max .

[0056] For example, if the electrostatic discharge protection level of the ESD protection structure 20 is required to be above 1500V, then the required current carrying capacity I of the ESD protection structure 20 is... max Approximately 1A. At this point, if the unit gate width current density J of each Schottky diode 211... SBD To achieve 200mA / mm (gate length approximately 4µm), the total gate width of diode group 21 needs to be 5mm. Therefore, if the gate width of a single finger of Schottky diode 211 is 0.5mm (i.e., the gate width W of Schottky diode 211...), gIf the width is 0.5mm, then diode group 21 needs to include 10 Schottky diodes 211 connected in parallel. Of course, it should be understood that the current density J per unit gate width of each Schottky diode 211 is... SBD The gate width W of the Schottky diode 211 is 200mA / mm. g The 0.5mm diameter and the electrostatic discharge protection level of the ESD protection structure 20 of 1500V or higher are examples provided in this application to facilitate user understanding and explanation of the above formulas, and should not be considered as limitations on this application. In other embodiments, the unit gate width current density J of the Schottky diode 211... SBD The gate width W of the Schottky diode 211 g The electrostatic voltage protection level of the ESD protection structure 20 should be determined by those skilled in the art based on actual needs. Correspondingly, the value of M only needs to satisfy the above formula M×J. SBD ×W g >I max That's all.

[0057] Among them, the gate width W of the aforementioned Schottky diode 211 g Corresponding to Figure 2 The width of the second electrode 33 of the Schottky diode 211 along the second direction b is shown in the figure. For example, if the total gate width of the ESD protection structure 20 (i.e., the total width of the ESD protection structure 20 along the second direction b) is 5 mm, the gate width W of a single Schottky diode 211 is... g When the diameter is 0.5mm, then the ESD protection structure 20 can connect ten diode groups 21 in parallel.

[0058] Furthermore, in this embodiment, optionally, the ratio of the length of the gate 11 of the depletion-type HEMT device body to the length of the anode of the Schottky diode 211 is between 1:2 and 1:10, and the length of the anode of the Schottky diode 211 is the length of the anode of the Schottky diode 211 along the anode and cathode arrangement direction of the Schottky diode 211.

[0059] Wherein, the length of the gate 11 of the depletion-type HEMT device body is the length of the gate 11 of the depletion-type HEMT device body along the arrangement direction of the source 12 and the drain 13 of the depletion-type HEMT device body, corresponding to... Figure 2 In this context, the length of the gate 11 of the depletion-type HEMT device body is the length of the gate 11 of the depletion-type HEMT device body along the second direction b; corresponding to... Figure 4 In this case, the length of the gate 11 of the depletion-type HEMT device body is the length of the gate 11 of the depletion-type HEMT device body along the third direction c.

[0060] The anode of Schottky diode 211 is the second electrode 33 of Schottky diode 211 mentioned in the text, and the cathode of Schottky diode 211 is the first electrode 31 of Schottky diode 211 mentioned in the text. Corresponding to... Figure 2 In the diagram, the length of the anode of the Schottky diode 211 is the length of the second electrode 33 of the Schottky diode 211 along the first direction a; corresponding to... Figure 4 In the above, the length of the anode of the Schottky diode 211 is the length of the second electrode 33 of the Schottky diode 211 along the third direction c.

[0061] In this embodiment, the arrangement of the diode group 21 can include various methods. The following will illustrate the arrangement of the diode group 21 with examples:

[0062] Please refer to Figure 2 As shown, in one embodiment, the Schottky diodes 211 in the diode group 21 are connected in parallel along the first direction a, and the diode group 21 is connected in series along the second direction b. The length of the gate pad 14 of the depletion-type HEMT device body along the first direction a is L, the length of the Schottky diode 211 along the first direction a is L1, and L / L1>M. The first direction a is the arrangement direction of the gate pad 14 and the drain pad 13 of the depletion-type HEMT device body, and the second direction b is the arrangement direction of the source 12 and the drain 13 of the depletion-type HEMT device body.

[0063] For example, if the length L of the gate pad 14 of the depletion-type HEMT device body along the first direction a is 100 μm, and the length L1 of the Schottky diode 211 along the first direction a is 10 μm, then 10 Schottky diodes 211 connected in parallel can be disposed below the gate pad 14 of the depletion-type HEMT device body. Of course, similarly, the specific values ​​of L and L1 mentioned above are merely examples given in this application and should not be regarded as limitations on this application.

[0064] In this embodiment, the gate pad 14 of the depletion-type HEMT device body has a length of l along the second direction b, the Schottky diode 211 has a length of l1 along the second direction b, and l / l1 > N.

[0065] For example, if the length l of the gate pad 14 of the depletion-type HEMT device body along the second direction b is 3 mm, and the length l1 of the Schottky diode 211 along the second direction b is 500 μm, then six Schottky diodes 211 connected in series can be arranged below the gate pad 14 of the depletion-type HEMT device body. In this way, N can be selected from six, five, four, three, two, or one.

[0066] Please refer to Figure 4As shown, in another embodiment, diode group 21 is connected in parallel along the third direction c, and Schottky diode 211 is connected in series along the third direction c; the length of gate pad 14 of the depletion-type HEMT device body along the third direction c is R, the length of Schottky diode 211 along the third direction c is R1, and R / R1 > M×N; the third direction c is the arrangement direction of the source 12 and the drain 13 of the depletion-type HEMT device body.

[0067] In this embodiment, the length of the gate pad 14 of the depletion-type HEMT device body along the fourth direction d is r, and the length of the Schottky diode 211 along the fourth direction d is r1; then r / r1>1, and the fourth direction d is the arrangement direction of the gate pad 14 and the drain pad 15 of the depletion-type HEMT device body.

[0068] In the second embodiment, when the ESD protection structure 20 is located below the source thickened metal of the depletion-type HEMT device body, and the orthographic projection of the ESD protection structure 20 on the substrate 16 of the depletion-type HEMT device body does not overlap with the orthographic projection of the active region of the depletion-type HEMT device body on the substrate 16 (e.g.) Figure 13 and Figure 14 (As shown); ESD protection structure 20 should meet the following requirements:

[0069] The voltage requirements are the same as when the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body, i.e., the gate voltage operating range of the depletion-type HEMT device body is -V. min To V max Between them, the ESD protection structure 20 includes N diode groups 21 connected in series, and the turn-on voltage of each diode group 21 is V. f Then N×V f >V min This ensures that the operating voltage of the ESD protection structure 20 is less than any point in the gate voltage operating range of the depletion-type HEMT device, so that the ESD protection structure 20 is not activated when the depletion-type HEMT device is operating, thus avoiding any impact on the normal operation of the depletion-type HEMT device.

[0070] Since this situation is the same as when the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body in the first embodiment described above, this application will not repeat the details here. Those skilled in the art can refer to the relevant description above.

[0071] Furthermore, in this embodiment, if the electrostatic voltage protection level of the ESD protection structure 20 is V ESD V ESDThe corresponding current value is I max The diode group 21 includes M Schottky diodes 211 connected in parallel. The depletion-type HEMT device body includes Q source thickened metal elements. The current density per unit gate width of the Schottky diodes 211 is J. SBD The gate width of the Schottky diode 211 is W. g Then M×Q×J SBD ×W g >I max .

[0072] Among them, V ESD The corresponding current value is I max The meaning of is the same as in the previous text, and will not be repeated here.

[0073] The difference between this embodiment and the first embodiment described above is that the ESD protection structure 20 is located below the thickened source metal, because... Figure 13 As shown, the source electrode thickening metal includes multiple (i.e., Q) elements. Therefore, the formula that this embodiment should satisfy is M×Q×J. SBD ×W g >I max In general, the principle of this embodiment is the same as the formula M×J in the first embodiment described above. SBD ×W g >I max Similarly, therefore, no further examples will be given here, and those skilled in the art can refer to the preceding text.

[0074] Diode group 21 is connected in parallel along the sixth direction e, and Schottky diode 211 is connected in series along the sixth direction e; the depletion-type HEMT device body includes multiple active regions arranged at intervals along the fifth direction f, the spacing between two adjacent active regions is h1, the length of Schottky diode 211 along the fifth direction f is s1, then h1 / s1>1; the fifth direction is the arrangement direction of the source 12 and the drain 13 of the depletion-type HEMT device body, and the sixth direction is the arrangement direction of the gate pad 14 and the drain pad 15 of the depletion-type HEMT device body.

[0075] Please refer to Figure 13 As shown, the depletion-type HEMT device body includes multiple active regions arranged at intervals along the fifth direction f, with a spacing of h1 between two adjacent active regions (corresponding to h1). Figure 13 In this context, the distance between two adjacent active regions is the distance between the source 12 of one depletion-type HEMT device body and the source 12 of another nearby depletion-type HEMT device body; corresponding to... Figure 14 The middle is Figure 14 The distance between the source 12 of the two depletion-type HEMT devices in the middle. Figure 15 This is the equivalent circuit diagram of the ESD protection structure 20 in this embodiment.

[0076] Furthermore, in this embodiment, the length of the source thickened metal of the depletion-type HEMT device body along the sixth direction e is h2, and the length of the Schottky diode 211 along the sixth direction e is s2, and h2 / (s2×M)>N. When the ESD protection structure 20 meets the above conditions, it can be ensured that the ESD protection structure 20 can be placed below the source thickened metal.

[0077] In the third embodiment, when a portion of the ESD protection structure 20 is located below the source thickened metal of the depletion-type HEMT device body, and the orthographic projection of the ESD protection structure 20 onto the substrate 16 of the depletion-type HEMT device body does not overlap with the orthographic projection of the active region of the depletion-type HEMT device body onto the substrate 16 (e.g.) Figure 13 and Figure 14 (As shown); another part of the ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body. In this case, the ESD protection structure 20 should also meet the corresponding conditions to ensure that it can be completely placed below the source thickening metal and the gate pad 14 of the depletion-type HEMT device body. The conditions that need to be met can be deduced by those skilled in the art through the first and second embodiments described above, so they will not be repeated here. In contrast, when the ESD protection structure 20 is divided into two parts, one part is placed below the gate pad 14 of the depletion-type HEMT device body and the other part is placed below the source thickening metal of the depletion-type HEMT device body, compared with placing it alone below the gate pad 14 of the depletion-type HEMT device body or placing it alone below the source thickening metal of the depletion-type HEMT device body, the area of ​​the Schottky diode 211 can be increased as much as possible, thereby improving the ESD protection level (because the area that can be placed is larger than that of the first and second embodiments described above).

[0078] It should be noted that, in this embodiment, the Schottky diodes 211 located below the gate pad 14 can be arranged horizontally (e.g., ...). Figure 4 As shown), it can also be arranged vertically (as shown). Figure 2 As shown in the figure, specifically, those skilled in the art can determine according to actual needs, and this application does not impose any restrictions.

[0079] Please refer to Figure 7 In another aspect, the present invention provides a method for fabricating a semiconductor device, the method comprising the following steps:

[0080] S100, an epitaxial structure 17 is formed on the substrate 16. The epitaxial structure 17 includes an active region and a passive region located outside the active region, such as... Figure 8 As shown.

[0081] The epitaxial structure 17 includes a buffer layer, a channel layer, and a barrier layer, etc. Since these are conventional layers of a depletion-type transistor and are well known to those skilled in the art, they will not be described in detail in this application.

[0082] S200, deposit metal material on the epitaxial structure 17 to form the source 12 and drain 13 of the depletion-type HEMT device body in the active region, and form the first electrode 31 of the diode group 21 in the passive region to obtain the first device, such as... Figure 8 As shown.

[0083] It should be noted that, as Figure 8 The illustration uses a diode group 21 comprising two parallel Schottky diodes 211 as an example, where the two spaced-apart first electrodes 31 are the cathodes of the two Schottky diodes 211. Those skilled in the art can determine the number of first electrodes 31 formed in step S200 based on the required number of parallel Schottky diodes 211 in the diode group 21. For example, if the diode group 21 requires three parallel Schottky diodes 211, then three spaced-apart first electrodes 31 need to be formed here, and so on.

[0084] S300, A first passivation layer 32 covering the passive and active regions is formed on the first device. Please refer to... Figure 9 As shown.

[0085] The thickness and material of the first passivation layer 32 can be conventionally selected by those skilled in the art based on the characteristics of the Schottky diode 211, and this application does not impose any restrictions.

[0086] S400: A first window exposing the passive region of the epitaxial structure 17 is formed on the first passivation layer 32, and a first etching window of the epitaxial structure 17 exposing the active region is formed between the source 12 and the drain 13 of the depletion-type HEMT device body. Metal material is deposited in the first window and the first etching window to form the second electrode 33 of the diode group 21 and the gate 11 of the depletion-type HEMT device body, respectively, to obtain the second device. The source 12 of the depletion-type HEMT device body is interconnected with the second electrode 33 of the diode group 21. Figure 10 As shown.

[0087] In this configuration, the source 12 of the depletion-type HEMT device is interconnected with the second electrode 33 of the diode group 21, thus, as... Figure 1As shown, this allows the anode of diode group 21 to be connected to the source 12 of the depletion-type HEMT device body. It should be noted that the number of first windows should be determined by the number of Schottky diodes 211. For example, if the number of Schottky diodes 211 is 2, then the corresponding number of first windows is also 2.

[0088] S500, a second passivation layer 34 covering the passive and active regions is formed on the second device, such as... Figure 11 As shown.

[0089] The material and thickness of the second passivation layer 34 can be selected by those skilled in the art, and this application does not impose any restrictions.

[0090] S600, a second window is formed on the second passivation layer 34 to expose the first electrode 31 of the diode group 21, a second etching window to expose the source 12 of the depletion-type HEMT device body, and a third etching window to expose the drain 13 of the depletion-type HEMT device body.

[0091] The second window is positioned to facilitate the connection of the gate pad 14 of the depletion-type HEMT device body to the first electrode 31 in subsequent steps. It should be understood that the number of second windows is the same as the number of Schottky diodes 211.

[0092] S700: Source thickening metal and drain thickening metal are formed on the source 12 and drain 13 of the depletion-type HEMT device body, respectively. Drain pad 15, interconnected with the drain thickening metal of the depletion-type HEMT device body, and gate pad 14, interconnected with the gate 11 of the depletion-type HEMT device body, are formed in the passive region. Gate pad 14 is interconnected with the first electrode 31 of diode group 21 through a second window. Diode group 21 is connected between the source 12 and gate pad 14 of the depletion-type HEMT device body to form an ESD protection structure 20. Diode group 21 includes Schottky diode 211, such as... Figure 12 As shown.

[0093] That is, when forming the gate 11 of the depletion-type HEMT device body, the gate pad 14 of the depletion-type HEMT device body is also formed, and the gate pad 14 is interconnected with the first electrode 31 of each Schottky diode 211. In this way, the anode (i.e., the second electrode 33) of the diode group 21 is connected to the source 12 of the depletion-type HEMT device body, and the cathode (i.e., the first electrode 31) of the diode group 21 is connected to the gate pad 14 of the depletion-type HEMT device body.

[0094] The diode group 21 forms an ESD protection structure 20, and the diode group 21 includes a Schottky diode 211. The ESD protection structure 20 is located below the gate pad 14 of the depletion-type HEMT device body. In this way, it can not only provide electrostatic protection, but also reduce the area occupied by the ESD protection structure 20 on the semiconductor device.

[0095] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A semiconductor device, characterized by, The ESD protection structure is located below the gate pad of the depletion-mode HEMT device body, and the ESD protection structure is located below the thickened metal of the source of the depletion-mode HEMT device body, and the normal projection of the ESD protection structure on the substrate of the depletion-mode HEMT device body does not overlap with the normal projection of the active region of the depletion-mode HEMT device body on the substrate; The gate voltage working range of the depletion mode HEMT device body is between -V min and V max , the ESD protection structure comprises N series diode groups, and the opening voltage of each diode group is V f , then N×V f >V min ; When the ESD protection structure is located below the gate pad of the depletion-type HEMT device body, the electrostatic discharge protection level of the ESD protection structure is V. ESD The V ESD The corresponding current value is I max The diode group comprises M Schottky diodes connected in parallel, and the unit gate width current density of the Schottky diodes is J. SBD The gate width of the Schottky diode is W. g Then M×J SBD ×W g >I max ; When the ESD protection structure is located below the source thickened metal of the depletion-type HEMT device body, and the orthographic projection of the ESD protection structure on the substrate of the depletion-type HEMT device body does not overlap with the orthographic projection of the active region of the depletion-type HEMT device body on the substrate; the electrostatic discharge protection level of the ESD protection structure is V. ESD The V ESD The corresponding current value is I max The diode group includes M Schottky diodes connected in parallel, the depletion-mode HEMT device body includes Q source-thickened metal elements, and the current density per unit gate width of the Schottky diode is J. SBD The gate width of the Schottky diode is W. g Then M×Q×J SBD ×W g >I max .

2. The semiconductor device according to claim 1, wherein The ratio of the length of the gate of the depletion-mode HEMT device body to the length of the anode of the Schottky diode is between 1:2 and 1:10, and the length of the anode of the Schottky diode is the length of the anode of the Schottky diode along the arrangement direction of the anode of the Schottky diode and the cathode of the Schottky diode.

3. The semiconductor device according to claim 1 or 2, wherein The Schottky diodes in the diode group are connected in parallel along a first direction, the diode group is connected in series along a second direction, the length of the gate pad of the depletion-mode HEMT device body along the first direction is L, the length of the Schottky diode along the first direction is L1, and L / L1>M, the first direction is the arrangement direction of the gate pad of the depletion-mode HEMT device body and the drain pad of the depletion-mode HEMT device body, and the second direction is the arrangement direction of the source of the depletion-mode HEMT device body and the drain of the depletion-mode HEMT device body.

4. The semiconductor device according to claim 3, wherein The length of the gate pad of the depletion-mode HEMT device body along the second direction is l , the length of the Schottky diode along the second direction is l 1, and l / l 1 > N.

5. The semiconductor device according to claim 1 or 2, wherein The diode group is connected in parallel along a third direction, and the Schottky diodes are connected in series along the third direction; the length of the gate pad of the depletion-mode HEMT device body along the third direction is R, the length of the Schottky diode along the third direction is R1, and R / R1>M×N; the third direction is the arrangement direction of the source of the depletion-mode HEMT device body and the drain of the depletion-mode HEMT device body.

6. The semiconductor device according to claim 5, wherein The length of the gate pad of the depletion-mode HEMT device body along a fourth direction is r, and the length of the Schottky diode along the fourth direction is r1; then r / r1>1, and the fourth direction is the arrangement direction of the gate pad of the depletion-mode HEMT device body and the drain pad of the depletion-mode HEMT device body.

7. A method of manufacturing a semiconductor device, characterized by The method comprises: forming an epitaxial structure on a substrate, the epitaxial structure comprising an active region and a passive region outside the active region; depositing a metal material on the epitaxial structure to form a source of a depletion-mode HEMT device body and a drain of the depletion-mode HEMT device body in the active region, and to form a first electrode of a diode group in the passive region, to obtain a first device; forming a first passivation layer covering the passive region and the active region on the first device; a first window exposing the epitaxial structure of the passive region and a first etching window between the source of the depletion-mode HEMT device body and the drain of the depletion-mode HEMT device body and exposing the epitaxial structure of the active region are formed on the first passivation layer, and a metal material is deposited in the first window and the first etching window to form a second electrode of the diode group and a gate of the depletion-mode HEMT device body, respectively, to obtain a second device, wherein the source of the depletion-mode HEMT device body is interconnected with the second electrode of the diode group; a second passivation layer covering the passive region and the active region is formed on the second device; a second window exposing the first electrode of the diode group, a second etching window exposing the source of the depletion-mode HEMT device body, and a third etching window exposing the drain of the depletion-mode HEMT device body are formed on the second passivation layer; a source thickening metal and a drain thickening metal are formed on the source of the depletion-mode HEMT device body and the drain of the depletion-mode HEMT device body, respectively, and a drain pad interconnected with the drain thickening metal of the depletion-mode HEMT device body and a gate pad interconnected with the gate of the depletion-mode HEMT device body are formed on the passive region, respectively, the gate pad being interconnected with the first electrode of the diode group through the second window, wherein the diode group is connected between the source of the depletion-mode HEMT device body and the gate pad of the depletion-mode HEMT device body to form an ESD protection structure, and the diode group comprises a Schottky diode.

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