Antenna tuning switch structure

Abstract

The invention discloses an antenna tuning switch structure. The antenna tuning switch structure comprises an epitaxial substrate, a gate structure, a source electrode and a drain electrode, the epitaxial substrate comprises a semiconductor substrate and a nitride heterostructure formed on the semiconductor substrate, two-dimensional electron gas is arranged in the nitride heterostructure, the gate structure is arranged on the nitride heterostructure, and the source electrode and the drain electrode are arranged on the opposite sides of the gate structure respectively. One of the source electrode and the drain electrode is connected with the antenna, the other of the source electrode and the drain electrode is connected with the tuning element, and the gate structure is used for controlling electric connection between the tuning element and the antenna. Therefore, the antenna tuning switch structure can improve the breakdown voltage, has low leakage current performance and high-power processing capability based on the two-dimensional electron gas, and is suitable for a high-power environment.

Description

TECHNICAL FIELD

[0001] The present application relates to a switch structure, and in particular to an antenna tuning switch structure. BACKGROUND

[0002] An antenna is an essential element in a mobile communication system with multiple operating frequency bands. An antenna tuner is disposed between an antenna and a radio frequency front end. The antenna tuner can provide adjustable impedance tuning through a tuning element, match the impedance between a transceiver and the antenna, and adjust the resonant frequency of the antenna, so as to improve the transmission efficiency and quality of signals.

[0003] The antenna tuner includes multiple switch circuits connected in parallel and a tuning element connected in series corresponding to each switch circuit. The existing switch circuit usually adopts at least twenty-five silicon-on-insulator (SOI) transistors connected in series to achieve a breakdown voltage of 100 volts (V), so as to be applicable to the antenna tuner in a high-power environment (for example, 34 dBm radio frequency power). However, since at least twenty-five SOI transistors are used to form the switch circuit in series, the non-linear change caused by the compensation of voltage change exists, and the linear control is poor.

[0004] Therefore, how to provide a solution to the above technical problems is a problem that needs to be solved by those skilled in the art at present. SUMMARY

[0005] The embodiment of the present application provides an antenna tuning switch structure, which can solve the problems of large size and poor linear control of the existing antenna tuner due to the need to connect at least twenty-five SOI transistors in series to achieve the requirement of high breakdown voltage, and the need to compensate for the non-linear change caused by the change in voltage.

[0006] In order to solve the above technical problems, the present application is implemented as follows:

[0007] The present application provides an antenna tuning switch structure, which includes a heteroepitaxial substrate, a gate structure, a source electrode, and a drain electrode. The heteroepitaxial substrate includes a semiconductor substrate and a nitride heterostructure formed on the semiconductor substrate, the nitride heterostructure having a two-dimensional electron gas therein, the gate structure being disposed on the nitride heterostructure, and the source electrode and the drain electrode being respectively disposed on opposite sides of the gate structure. When the source electrode is connected to an antenna, the drain electrode is connected to a tuning element; when the drain electrode is connected to the antenna, the source electrode is connected to the tuning element; and the gate structure is used to control the electrical connection between the tuning element and the antenna.

[0008] In this embodiment, the antenna tuning switch structure improves the breakdown voltage through the wide bandgap characteristics of the nitride heterostructure. This allows the antenna tuner's switching circuit to meet the requirements of high-power antenna switches used in modern communication systems with only a single antenna tuning switch structure or a small number of antenna tuning switch structures connected in series. Furthermore, because a small number of antenna tuning switch structures are connected in series, there is no need to compensate for nonlinear changes caused by voltage variations. Therefore, the switching circuit of the antenna tuner using this antenna tuning switch structure has a miniaturized size and better linear control, and is suitable for high-output-power operating systems. In addition, the antenna tuning switch structure can leverage the low leakage current performance and high power handling capability of the two-dimensional electron gas within the nitride heterostructure. Attached Figure Description

[0009] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0010] Figure 1 A schematic diagram of an embodiment of an RF circuit including an antenna tuner employing the antenna tuning switch structure of this application;

[0011] Figure 2 for Figure 1 A schematic diagram of the first embodiment of the antenna tuner connecting to the antenna;

[0012] Figure 3 for Figure 1 A schematic diagram of a second embodiment of the antenna tuner connecting to the antenna; and

[0013] Figure 4 for Figure 1 A schematic diagram of the third embodiment of the antenna tuner connecting to the antenna. Detailed Implementation

[0014] The embodiments of the present invention will be described below with reference to the accompanying drawings. Directional terms used in the following embodiments, such as up, down, left, right, front, and back, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the invention. In these drawings, the same reference numerals denote the same or similar elements or method flows.

[0015] It must be understood that the terms "comprising," "including," etc., used in this specification are intended to indicate the presence of specific technical features, values, method steps, work processes, and / or components, but do not preclude the addition of more technical features, values, method steps, work processes, components, or any combination thereof. The term "and / or" as used in this specification includes any one or more associated items and all combinations thereof.

[0016] It must be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0017] Referring to Figure 1 , which is a schematic diagram of an embodiment of a radio frequency circuit of an antenna tuner including the antenna tuning switch structure of the present application. As Figure 1 shown, the radio frequency circuit 100 includes a radio frequency front end 110, an antenna tuner 121, an antenna tuner 122, an antenna 131, and an antenna 132. The radio frequency front end 110 includes a first signal receiving end 11, a first signal output end 21, a first power amplifier 31, a first single pole double throw (SPDT) switch 41, a first filter 51, a first low noise amplifier (LNA) 61, a first double pole double throw (DPDT) switch 71, a first coupler 81, a second signal receiving end 12, a second signal output end 22, a second power amplifier 32, a second SPDT switch 42, a second filter 52, a second LNA 62, a second DPDT switch 72, and a second coupler 82.

[0018] The antennas 131 and 132 can be single stage antennas, inverted F-shaped antennas (IFAs), loop antennas, dipole antennas, or planar inverted-F antennas (PIFAs). The first power amplifier 31 is configured to amplify radio frequency signals having a first frequency band from the first signal output end 21, and the second power amplifier 32 is configured to amplify radio frequency signals having a second frequency band from the second signal output end 22.

[0019] The first filter 51 is a band pass filter configured to pass radio frequency (RF) signals in the first frequency band, and the second filter 52 is a band pass filter configured to pass radio frequency signals in the second frequency band. The band pass filters can be filters configured to pass radio frequency signals (e.g., with less than 3 dB attenuation) within a frequency band. The first filter 51 and the second filter 52 can include acoustic filters, inductor-capacitor (LC) filters, cavity filters, combinations thereof, and the like. The acoustic filters can include surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, and the like. The first frequency band can be an LTE frequency band, and the second frequency band can be a wireless local area network (WLAN) frequency band.

[0020] The first low noise amplifier 61 is configured to amplify the radio frequency signal with the first frequency band passing through the first filter 51, and output the amplified radio frequency signal with the first frequency band; the second low noise amplifier 62 is configured to amplify the radio frequency signal with the second frequency band passing through the second filter 52, and output the amplified radio frequency signal with the second frequency band. The first coupler 81 and the second coupler 82 can be, but are not limited to, directional couplers.

[0021] The antenna tuner 121 is connected to the antenna 131, and the antenna tuner 122 is connected to the antenna 132. The antennas 131 and 132 are used to transceive signals of different frequency bands. The antenna tuner 121 is used to match the impedance of the antenna 131 and the radio frequency front end 110 and adjust the resonant frequency of the antenna 131. The antenna tuner 122 is used to match the impedance of the antenna 132 and the radio frequency front end 110 and adjust the resonant frequency of the antenna 132.

[0022] After the first signal output end 21 receives the radio frequency signal with the first frequency band from the radio frequency transceiver (not drawn), the transmission path of the radio frequency signal with the first frequency band is: transmitted to the antenna 131 via the first power amplifier 31, the first single-pole double-throw switch 41, the first filter 51, the second double-pole double-throw switch 72, the first coupler 81, and the antenna tuner 121, so that the antenna 131 can convert the radio frequency signal with the first frequency band into electromagnetic waves with the first frequency band, and radiate the electromagnetic waves with the first frequency band out; the antenna 131 can receive electromagnetic waves with the first frequency band in space, and convert the electromagnetic waves with the first frequency band into a radio frequency signal with the first frequency band, and the transmission path of the radio frequency signal with the first frequency band is: transmitted to the radio frequency transceiver after passing through the antenna tuner 121, the first coupler 81, the second double-pole double-throw switch 72, the first filter 51, the first single-pole double-throw switch 41, the first low noise amplifier 61, the first double-pole double-throw switch 71, and the first signal receiving end 11.

[0023] The second signal output end 22 receives the radio frequency signal with the second frequency band from the radio frequency transceiver, and the transmission path of the radio frequency signal with the second frequency band is: transmitted to the antenna 132 via the second power amplifier 32, the second single-pole double-throw switch 42, the second filter 52, the second double-pole double-throw switch 72, the second coupler 82, and the antenna tuner 122, so that the antenna 132 can convert the radio frequency signal with the second frequency band into an electromagnetic wave with the second frequency band, and radiate the electromagnetic wave with the second frequency band; the antenna 132 can receive the electromagnetic wave with the second frequency band in space, and convert the electromagnetic wave with the second frequency band into a radio frequency signal with the second frequency band, and the transmission path of the radio frequency signal with the second frequency band is: transmitted to the radio frequency transceiver via the antenna tuner 122, the second coupler 82, the second double-pole double-throw switch 72, the second filter 52, the second single-pole double-throw switch 42, the second low-noise amplifier 62, the first double-pole double-throw switch 71, and the second signal receiving end 12.

[0024] The antenna tuner 121, the antenna tuner 122, the first single-pole double-throw switch 41, the first double-pole double-throw switch 71, the second single-pole double-throw switch 42, and the second double-pole double-throw switch 72 can be controlled by the radio frequency transceiver. The circuit architecture of the antenna tuner 121 and the circuit architecture of the antenna tuner 122 can be the same or different, and can be adjusted and designed according to actual needs.

[0025] The radio frequency circuit 100 can be applied to electronic communication devices, mobile devices, clients, user equipment (UE), remote stations, access terminals, mobile terminals, user terminals, etc. The electronic communication devices can include laptop or desktop computers, cellular phones, smart phones, wireless modems, e-readers, tablet devices, game systems, etc. The antenna tuner 121 can be a high-power antenna tuner, such as a 4G antenna tuner or a 5G antenna tuner applied to a smart phone, a WiFi antenna tuner applied to a router, an Internet of Things (IoT) radio frequency front-end antenna tuner or a transfer switch applied to a wireless module, but the embodiment is not used to limit the application.

[0026] Please refer to Figure 1 and Figure 2 , Figure 2 is Figure 1Fig. 1 is a schematic diagram of a first embodiment of an antenna tuner connected with an antenna. The switch circuit 1211 of the antenna tuner 121 can employ a single antenna tuning switch structure 200 (i.e., the antenna tuning switch structure 200 is applied to the antenna tuner 121), but the present embodiment is not intended to limit the present application. For example, the switch circuit 1211 of the antenna tuner 121 can employ a plurality of antenna tuning switch structures 200 connected in series, and the number of the antenna tuning switch structures 200 connected in series can be adjusted according to actual needs.

[0027] The antenna tuning switch structure 200 includes an epitaxial substrate 210, a gate structure 220, a source electrode 230, and a drain electrode 240. The epitaxial substrate 210 includes a semiconductor substrate 211 and a nitride heterostructure 212 formed on the semiconductor substrate 211, and the nitride heterostructure 212 has a two-dimensional electron gas 90 therein. The two-dimensional electron gas 90 refers to a phenomenon that an electron gas can move freely in two dimensions and is limited in the third dimension, which can significantly improve the carrier / electron migration speed of the antenna tuning switch structure 200. The two-dimensional electron gas 90 is a conductive channel of the antenna tuning switch structure 200. The gate structure 220 is disposed on the nitride heterostructure 212, and the source electrode 230 and the drain electrode 240 are respectively disposed on opposite sides of the gate structure 220. When the source electrode 230 is connected to the antenna 131, the drain electrode 240 is connected to the tuning element 1212; when the drain electrode 240 is connected to the antenna 131, the source electrode 230 is connected to the tuning element 1212; and the gate structure 220 is used to control the electrical connection between the tuning element 1212 and the antenna 131. The tuning element 1212 connected to the source electrode 230 or the drain electrode 240 can be a capacitor or an inductor, and the number of the tuning elements 1212 connected to the source electrode 230 or the drain electrode 240 can be one or more. When the number of the tuning elements 1212 connected to the source electrode 230 or the drain electrode 240 is more than one, the tuning elements 1212 can be connected in series, in parallel, or partially in series and partially in parallel to generate different impedance values. The tuning elements 1212 with matching impedance values and their connection modes can be selected according to actual needs.

[0028] It should be noted that, in order to facilitate the description and help understand the structure of the antenna tuning switch structure 200 of the present application, spatial reference directions such as a first direction F1, a second direction F2, and a third direction F3 are shown in the drawings of the present application. The first direction F1 and the second direction F2 are perpendicular to each other and parallel to the surface of the epitaxial substrate 210, and the third direction F3 is perpendicular to the surface of the epitaxial substrate 210.

[0029] In the embodiment, the source electrode 230 can be connected to the antenna 131, the drain electrode 240 can be connected to the tuning element 1212, the tuning element 1212 can be a capacitor, the source electrode 230 and the drain electrode 240 are respectively disposed on opposite sides of the gate structure 220 in the second direction F2; the antenna tuning switch structure 200 can be, but is not limited to, a high electron mobility transistor (HEMT), and the radio frequency transceiver can be used to control the gate structure 220, but the embodiment is not intended to limit the present application.

[0030] The wide energy gap characteristic of the nitride heterostructure 212 improves the breakdown voltage of the antenna tuning switch structure 200, so that when the antenna tuning switch structure 200 is applied to the antenna tuner 121, the antenna tuning switch structure 200 can achieve high breakdown voltage and meet the needs of high-power antenna switches. Compared with the existing antenna tuner which requires at least twenty-five silicon-on-insulator transistors in series, the antenna tuner 121 does not need to use compensation for the non-linear changes caused by voltage changes, so that the antenna tuner 121 using the antenna tuning switch structure 200 has a small size and better linear control, and is suitable for high-output power operating systems.

[0031] In an embodiment, when the switch circuit 1211 of the antenna tuner 121 includes M antenna tuning switch structures 200 connected in series and M is a positive integer greater than or equal to 2, the drain electrode 240 of the first antenna tuning switch structure 200 in the series-connected antenna tuning switch structures 200 can be connected to the tuning element 1212, the source electrode 230 of the Mth antenna tuning switch structure 200 in the series-connected antenna tuning switch structures 200 can be connected to the antenna 131, and if M is a positive integer greater than or equal to 3, the drain electrode 240 of the Kth antenna tuning switch structure 200 (1 < K < M) can be connected to the source electrode 230 of the antenna tuning switch structure 200 on one side, and the source electrode 230 of the Kth antenna tuning switch structure 200 can be connected to the drain electrode 240 of the antenna tuning switch structure 200 on the other side. In other words, the drain electrode 240 of each antenna tuning switch structure 200 in the series-connected antenna tuning switch structures 200 can be directly or indirectly connected to the tuning element 1212, and the source electrode 230 of each antenna tuning switch structure 200 in the series-connected antenna tuning switch structures 200 can be directly or indirectly connected to the antenna 131.

[0032] In another embodiment, when the switch circuit 1211 of the antenna tuner 121 includes M antenna tuning switch structures 200 connected in series and M is a positive integer greater than or equal to 2, the source electrode 230 of a first antenna tuning switch structure 200 of the series-connected antenna tuning switch structures 200 can be connected to the tuning element 1212, the drain electrode 240 of an Mth antenna tuning switch structure 200 of the series-connected antenna tuning switch structures 200 can be connected to the antenna 131, and if M is a positive integer greater than or equal to 3, the source electrode 230 of a Kth antenna tuning switch structure 200 (1 < K < M) can be connected to the drain electrode 240 of an adjacent antenna tuning switch structure 200, and the drain electrode 240 of the Kth antenna tuning switch structure 200 can be connected to the source electrode 230 of another adjacent antenna tuning switch structure 200. In other words, the source electrode 230 of each antenna tuning switch structure 200 of the series-connected antenna tuning switch structures 200 can be directly or indirectly connected to the tuning element 1212, and the drain electrode 240 of each antenna tuning switch structure 200 of the series-connected antenna tuning switch structures 200 can be directly or indirectly connected to the antenna 131.

[0033] In an embodiment, the semiconductor substrate 211 can be, but is not limited to, a substrate with a resistivity greater than 500 ohm-cm. Since the nitride heterostructure 212 is formed on the high-resistivity semiconductor substrate 211, the isolation degree can be improved to avoid radio frequency signal loss. The material of the semiconductor substrate 211 can include, but is not limited to, float zone silicon, gallium nitride, aluminum nitride, silicon carbide, sapphire, or diamond. The float zone silicon is a silicon substrate grown by a float zone growth method.

[0034] In an embodiment, the nitride heterostructure 212 can include a buffer layer 2121 formed on the semiconductor substrate 211, a nitride channel layer 2122 formed on the buffer layer 2121, and a Schottky layer 2123 formed on the nitride channel layer 2122, a two-dimensional electron gas 90 is formed in the nitride channel layer 2122 near the interface between the nitride channel layer 2122 and the Schottky layer 2123. The linear control can be improved by the design of the buffer layer 2121 and the nitride channel layer 2122. The buffer layer 2121, the nitride channel layer 2122, and the Schottky layer 2123 can be formed by epitaxial growth processes, such as metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), combinations thereof, or other similar methods.

[0035] In an embodiment, the buffer layer 2121 can include an aluminum gallium nitride superlattice layer, a gallium aluminum nitride back barrier layer, an aluminum nitride back barrier layer, and / or a grading / abrupt gallium nitride buffer layer. The aluminum gallium nitride superlattice layer and the grading / abrupt gallium nitride buffer layer can be used as a stress buffer layer to improve the stress adjustment capability and reduce the radio frequency signal leakage through the semiconductor substrate 211. The grading / abrupt gallium nitride buffer layer provides a gradual lattice constant. The gallium aluminum nitride back barrier layer or the aluminum nitride back barrier layer can be used to prevent current collapse caused by surface polarization effect.

[0036] In an embodiment, the material of the nitride channel layer 2122 can include, but is not limited to, gallium nitride, gallium aluminum nitride, indium aluminum nitride, aluminum nitride, scandium gallium nitride, scandium aluminum nitride, boron nitride, aluminum indium gallium nitride, and / or indium gallium nitride. The material of the Schottky layer 2123 can include, but is not limited to, gallium nitride, gallium aluminum nitride, indium aluminum nitride, aluminum nitride, scandium gallium nitride, scandium aluminum nitride, boron nitride, aluminum indium gallium nitride, and / or indium gallium nitride. The material of the nitride channel layer 2122 is different from the material of the Schottky layer 2123. A potential drop is formed at the interface between the nitride channel layer 2122 and the Schottky layer 2123. The free carriers are affected by the polarization field distribution and are gathered in the potential drop, so the two-dimensional electron gas 90 is generated in the nitride channel layer 2122 near the Schottky layer 2123.

[0037] In one embodiment, the distance between the gate structure 220 and the source electrode 230 can be the same as or different from the distance between the gate structure 220 and the drain electrode 240.

[0038] In one embodiment, the number of gate structures 220 may be a single one (e.g., Figure 2 (As shown). In another embodiment, the number of gate structures 220 can be multiple, and the source electrode 230 and drain electrode 240 are respectively disposed on opposite sides of the multiple gate structures 220 (e.g., Figure 3 As shown, Figure 3 for Figure 1 (A schematic diagram of a second embodiment of the antenna tuner connected to the antenna) wherein the RF transceiver can simultaneously control multiple gate structures 220 through a single control terminal 60; the arrangement of multiple gate structures 220 can improve the breakdown voltage of the antenna tuning switch structure 200. Additionally, in Figure 3 In the middle, the source electrode 230 can be connected to the tuning element 1212, and the number of tuning elements 1212 can be two. The two tuning elements 1212 can be a capacitor and an inductor connected in series. The drain electrode 240 can be connected to the antenna 131.

[0039] In one embodiment, the distance between any two adjacent gate structures 220 may be the same or different.

[0040] In one embodiment, the gate structure 220 may be a metal-insulator-semiconductor (MIS) structure (e.g., Figure 2 As shown, the metal-insulating semiconductor structure includes a dielectric layer 91 in contact with the nitride heterostructure 212 and a gate electrode 92 disposed on the dielectric layer 91. The material of the gate electrode 92 may include titanium, aluminum, nickel, gold, platinum, chromium, copper, iridium, titanium nitride, its compounds, its composite layers, or alloys thereof. The material of the dielectric layer 91 may include silicon nitride, silicon oxide, hafnium oxide, or aluminum oxide, but this embodiment is not intended to limit this application. By designing the gate structure 220 as a metal-insulating semiconductor structure, the gate leakage current of the antenna tuning switch structure 200 can be reduced, and the breakdown capability of the antenna tuning switch structure 200 can be improved. The dielectric layer 91 can be formed by atomic layer deposition (ALD) process. ALD deposition technology is suitable for the deposition of dielectric layer 91 because it has good uniformity, thickness control, low deposition temperature (thermal treatment budget), and no plasma deposition (which can avoid plasma-induced damage to the underlying epitaxial layer).

[0041] In another embodiment, the gate structure 220 may include a gallium nitride layer 93 in contact with the nitride heterostructure 212 and a gate electrode 94 disposed on the gallium nitride layer 93 (e.g., ...).Figure 3 As shown, the gate electrode 94 can form a Schottky contact with the gallium nitride layer 93. The gate electrode 94 can be made of titanium, aluminum, nickel, gold, platinum, chromium, copper, iridium, titanium nitride, or compounds thereof. The contact between the gate electrode 94 and the gallium nitride layer 93 creates a Schottky barrier at their contact surface (i.e., the heterojunction), which improves the breakdown capability and noise immunity of the antenna tuning switch structure 200.

[0042] In yet another embodiment, the gate structure 220 is a P-type gallium nitride gate (e.g., Figure 4 As shown, Figure 4 for Figure 1 (A schematic diagram of the third embodiment of the antenna tuner connecting to the antenna). The P-type gallium nitride gate includes carbon-doped gallium nitride or magnesium-doped gallium nitride. Furthermore, the P-type gallium nitride gate is used to deplete the charge carriers generated in the underlying nitride channel layer 2122, causing the antenna tuning switch structure 200 to transition to a normally-off state. Moreover, the P-type gallium nitride gate can be formed using epitaxial growth processes, such as metal-organic chemical vapor deposition, molecular beam epitaxy, or hydride vapor phase epitaxy, and the pattern of the P-type gallium nitride gate is defined using photolithography. Additionally, in... Figure 4 In the middle, the source electrode 230 can be connected to the tuning element 1212, and the number of tuning elements 1212 can be two. The two tuning elements 1212 can be a capacitor and an inductor connected in parallel. The drain electrode 240 can be connected to the antenna 131.

[0043] In one embodiment, the gate structure 220, source electrode 230, and drain electrode 240 are in direct contact with the nitride heterostructure 212. Specifically, when the epitaxial substrate 210 includes a semiconductor substrate 211, a buffer layer 2121, a nitride channel layer 2122, and a Schottky layer 2123 stacked in sequence, the gate structure 220, source electrode 230, and drain electrode 240 are in direct contact with the Schottky layer 2123 (e.g., ...). Figure 2 and Figure 3 (As shown).

[0044] In another embodiment, the gate structure 220, the source electrode 230 and the drain electrode 240 can extend into the nitride heterostructure 212 (i.e. in the opposite direction of the third direction F3) in addition to directly contacting the nitride heterostructure 212. For example, when the epitaxial substrate 210 includes a semiconductor substrate 211, a buffer layer 2121, a nitride channel layer 2122 and a Schottky layer 2123 stacked in sequence, the gate structure 220, the source electrode 230 and the drain electrode 240 can directly contact the Schottky layer 2123 in addition to extending into the Schottky layer 2123 and / or the nitride channel layer 2122, or even the source electrode 230 and the drain electrode 240 can directly contact the two-dimensional electron gas 90 (as shown in Figure 4 By extending the source electrode 230 and the drain electrode 240 into the nitride heterostructure 212, respectively, a larger contact area between the source electrode 230 and the drain electrode 240 and the nitride heterostructure 212 can be achieved, which can result in a lower contact resistance of the antenna tuning switch structure 200 and thus a superior performance of the antenna tuning switch structure 200 during operation.

[0045] In an embodiment, the source electrode 230 and the drain electrode 240 can form an ohmic contact with the nitride heterostructure 212, respectively. The source electrode 230 and the drain electrode 240 can include a conductive material, which can include titanium, aluminum, nickel, silver, gold, platinum, chromium, copper, iridium, titanium nitride and tungsten, a compound thereof, a composite layer thereof or an alloy thereof, but is not limited thereto. In addition, the source electrode 230 and the drain electrode 240 can also be a stacked layer that forms an ohmic contact with the epitaxial substrate 210, such as Ti / Al, Ti / Al / Ti / TiN, Ti / Al / Ti / Au or Ti / Al / Ni / Au, but is not limited thereto.

[0046] In summary, the antenna tuning switch structure improves the breakdown voltage by the wide energy gap characteristic of the nitride heterostructure, so that the switch circuit of the antenna tuner only needs a single antenna tuning switch structure or a small number of antenna tuning switch structures connected in series to meet the requirements of the high-power antenna switch, and does not need to compensate for the nonlinear changes caused by voltage changes due to the connection of a small number of antenna tuning switch structures in series, so that the switch circuit of the antenna tuner using the antenna tuning switch structure has a small size and better linear control, and is suitable for high-output power operating systems. In addition, the antenna tuning switch structure can have low leakage current performance and high power handling capability based on the two-dimensional electron gas in the nitride heterostructure. Furthermore, the nitride heterostructure is formed on a semiconductor substrate with high resistivity (i.e., resistivity greater than 500 ohm-cm), which can improve the isolation degree and thus avoid radio frequency signal loss. In addition, by providing multiple gate structures, the breakdown voltage of the antenna tuning switch structure can be improved. Furthermore, by designing the gate structure as a metal-insulator-semiconductor structure, the gate leakage current can be reduced, and the breakdown capability of the antenna tuning switch structure can be improved.

[0047] Although the present application has been described with reference to the above embodiments, it is noted that these descriptions are not intended to limit the present application. On the contrary, the present application covers modifications and similar arrangements as would be apparent to one skilled in the art. Accordingly, the scope of the application should be interpreted in accordance with the fullest broadest interpretation so as to embrace all such modifications and similar structures.

Claims

1. An antenna tuning switch structure, characterized in that, include: An epitaxial substrate includes a semiconductor substrate and a nitride heterostructure formed on the semiconductor substrate, wherein the nitride heterostructure contains a two-dimensional electron gas; A gate structure is disposed on the nitride heterostructure; as well as The source electrode and drain electrode are respectively disposed on opposite sides of the gate structure. When the source electrode is connected to the antenna, the drain electrode is connected to the tuning element; when the drain electrode is connected to the antenna, the source electrode is connected to the tuning element. The gate structure is used to control the electrical connection between the tuning element and the antenna.

2. The antenna tuning switch structure as described in claim 1, characterized in that, The gate structure is a metal-insulator-semiconductor structure, which includes a dielectric layer in contact with the nitride heterostructure and a gate electrode disposed on the dielectric layer.

3. The antenna tuning switch structure as described in claim 1, characterized in that, The gate structure includes a gallium nitride layer in contact with the nitride heterostructure and a gate electrode disposed on the gallium nitride layer, wherein a Schottky contact is formed between the gate electrode and the gallium nitride layer.

4. The antenna tuning switch structure as described in claim 1, characterized in that, The gate structure is a P-type gallium nitride gate.

5. The antenna tuning switch structure as described in claim 1, characterized in that, The nitride heterostructure includes a buffer layer formed on the semiconductor substrate, a nitride channel layer formed on the buffer layer, and a Schottky layer formed on the nitride channel layer. The two-dimensional electron gas is formed in the nitride channel layer near the interface between the nitride channel layer and the Schottky layer.

6. The antenna tuning switch structure as described in claim 5, characterized in that, The buffer layer includes an aluminum nitride / galvanic aluminum nitride superlattice layer, an aluminum gallium nitride back barrier layer, an aluminum nitride back barrier layer, and / or a graded / abrupt gallium nitride buffer layer.

7. The antenna tuning switch structure as described in claim 5, characterized in that, The material of the nitride channel layer includes gallium nitride, aluminum gallium nitride, indium aluminum nitride, aluminum nitride, scandium gallium nitride, scandium aluminum nitride, boron nitride, aluminum indium gallium nitride, and / or indium gallium nitride.

8. The antenna tuning switch structure as described in claim 5, characterized in that, The material of the Schottky base layer includes gallium nitride, aluminum gallium nitride, indium aluminum nitride, aluminum nitride, scandium gallium nitride, scandium aluminum nitride, boron nitride, aluminum indium gallium nitride and / or indium gallium nitride.

9. The antenna tuning switch structure as described in claim 1, characterized in that, The semiconductor substrate is a substrate with a resistivity greater than 500 ohm-cm.

10. The antenna tuning switch structure as described in claim 1 or 9, characterized in that, The semiconductor substrate is made of materials including floating silicon, gallium nitride, aluminum nitride, silicon carbide, sapphire, or diamond.

11. The antenna tuning switch structure as described in claim 1, characterized in that, The source electrode and the drain electrode respectively form ohmic contacts with the nitride heterostructure.

12. The antenna tuning switch structure as described in claim 1, characterized in that, The number of gate structures is multiple, and the source electrode and the drain electrode are respectively disposed on opposite sides of the multiple gate structures.

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