Monolithic microwave integrated circuit front-end module

Abstract

A monolithic microwave integrated circuit (MMIC) front-end module (100), comprising: a gallium nitride structure (110) supported by a silicon substrate (120); a silicon-based transmit / receive switch (130) having a transmit mode and a receive mode; a transmit amplifier (112) configured to amplify an outgoing signal transmitted by the MMIC front-end module, the transmit amplifier being electrically connected (132) to the transmit / receive switch, the transmit amplifier comprising a gallium nitride high electron mobility transistor (HEMT) (114) formed within the gallium nitride structure; a receive amplifier (113) configured to amplify an incoming signal received by the MMIC front-end module, the receive amplifier being electrically connected (133) to the transmit / receive switch, the receive amplifier comprising a gallium nitride HEMT (115) formed within the gallium nitride structure; 1. An MMIC front-end module comprising:

Description

[Technical Field]

[0001] The present invention relates to a radio frequency (RF) transceiver front-end module, and more particularly to a monolithic microwave integrated circuit (MMIC) front-end module. [Background technology]

[0002] In many applications, such as RF amplifiers, conventional silicon complementary metal-oxide semiconductor (CMOS) transistors have reached their performance limits. Gallium nitride-based transistors and high-electron-mobility transistors (HEMTs) offer improved performance compared to conventional silicon counterparts. However, due to the overall technological maturity of silicon CMOS technology, silicon remains desirable for various applications, such as digital logic and switching. Therefore, it would be desirable to have integrated RF circuits that include both silicon and gallium nitride devices, such as transistors, switches, converters, and amplifiers. However, such integration is not straightforward, in part due to differences in material properties. This difference makes integrating high-quality gallium nitride onto conventional silicon substrates particularly complicated. This is problematic because, for example, high-performance HEMTs require high-quality gallium nitride material. Conventional solutions to this problem can include thick and complex buffer layers or structures. However, these are not consistently sufficient beyond mitigating the degradation due to integration. The added thickness of the buffer layers or structures also disadvantageously increases material usage. Thus, there is a need for improvements in the art. Summary of the Invention

[0003] One of the aims of the present invention is to alleviate at least some of the problems of the prior art.

[0004] According to a first aspect of the present invention, there is provided a monolithic microwave integrated circuit (MMIC) front-end module, comprising: a gallium nitride structure supported by a silicon substrate; a silicon-based transmit / receive switch having a transmit mode and a receive mode; a transmit amplifier configured to amplify an outgoing signal transmitted by the MMIC front-end module, the transmit amplifier electrically connected to the transmit / receive switch, the transmit amplifier comprising a gallium nitride high electron mobility transistor (HEMT) formed in a gallium nitride structure; a receive amplifier configured to amplify an incoming signal received by the MMIC front-end module, the receive amplifier electrically connected to the transmit / receive switch, the receive amplifier comprising a gallium nitride HEMT formed in a gallium nitride structure; Equipped with.

[0005] The term "gallium nitride structure" should be understood to refer to a laterally confined structure, i.e., a layer that does not cover the entire silicon substrate area. Gallium nitride structure should further be understood as a structure comprising any degree of gallium nitride material.

[0006] The term "supported" refers to the gallium nitride structure being located on or above the silicon substrate in a vertical direction perpendicular to and orthogonal to the top surface of the silicon substrate.

[0007] The terms "transmit mode" and "receive mode" refer to having a transmit / receive switch adapted to transmit or receive wireless signals. In effect, in the transmit mode, the switch is adapted to provide a more direct electrical path between the transmit amplifier and the antenna for outgoing signals, and in the receive mode, the switch is adapted to provide a more direct electrical path between the antenna and the receive amplifier for incoming signals. The transmit mode may be understood as a mode in which the MMIC front-end module can transmit outgoing wireless signals. The receive mode may be understood as a mode in which the MMIC front-end module can receive incoming wireless signals. The MMIC front-end module may also be understood as a transceiver because it has both a transmit mode and a receive mode.

[0008] The term "transmit amplifier" may be generally understood as an RF power amplifier (PA), and the term "receive amplifier" may be generally understood as an RF low-noise amplifier (LNA).

[0009] Materials, ie, elements and compounds, may be referred to either by their full names, such as silicon or gallium nitride, or by their IUPAC symbols / names, such as Si or GaN.

[0010] The terms "outgoing signal" and "incoming signal" may be understood as an electrical signal on an electrical node, e.g., a voltage or current, or an electromagnetic signal in a free-space medium, e.g., air or vacuum, e.g., radio waves. The signal may be converted between purely electrical and electromagnetic by an antenna that is part of or connected to the MMIC front-end module. The signal may be processed through components of the MMIC front-end module, e.g., amplifiers and frequency converters.

[0011] An outgoing signal may still be an outgoing signal after being frequency upconverted by a frequency converter, amplified by a transmit amplifier, and / or transmitted into free space by an antenna. Similarly, an incoming signal may still be an incoming signal after being received by an antenna, amplified by a receive amplifier, and / or frequency downconverted by a frequency converter.

[0012] By providing gallium nitride structures on or above a silicon substrate, the inventors have realized that gallium nitride HEMT devices can be more closely integrated with silicon-based transmit / receive switches and other silicon-based devices and components as part of transmit and receive amplifiers. This has the advantage that gallium nitride can be used only where it is most needed, e.g., in the amplifiers, instead of only having silicon-based components / devices in the MMIC that are less critical or have different requirements.

[0013] Gallium nitride materials may feature larger bandgaps, higher electron mobility, improved thermal conductivity, and higher melting points compared to conventional silicon materials, which in turn may lead to devices such as transistors with higher switching frequencies, lower energy losses, higher voltage operation, and higher temperature operation.

[0014] HEMTs may offer advantages over conventional metal-oxide-semiconductor field-effect transistors (MOSFETs): HEMTs may offer ballistic charge carrier conduction with lower electrical resistance, which translates into improved efficiency, speed, and power capabilities of HEMTs.

[0015] As a result of employing HEMT and gallium nitride materials, the MMIC front-end module may offer lower power consumption and overall more efficient operation compared to conventional solutions and devices in the art.

[0016] The transmit amplifier may comprise multiple HEMTs formed in a gallium nitride structure.

[0017] The receiving amplifier may comprise multiple HEMTs formed in a gallium nitride structure.

[0018] The transmit amplifier, and indeed the receive amplifier, may each be fabricated with a single HEMT or multiple HEMTs, depending on the design chosen for the amplifier circuit. Less complex amplifiers feature fewer HEMTs or even just one HEMT, while more complex multiple HEMT amplifiers may offer improved amplifier performance metrics, such as higher frequency operation and lower power loss.

[0019] The gallium nitride structure supported by the silicon substrate comprises a first gallium nitride island and a second gallium nitride island, the first gallium nitride island and the second gallium nitride island being physically spaced apart and laterally co-located on the silicon substrate.

[0020] One advantage of providing a gallium nitride structure as multiple islands can be improved thermal properties. Instead of expanding and contracting as a single structure with temperature changes, the islands can do so individually and independently. In this way, the mechanical stress of expansion and contraction can be distributed throughout the islands. Therefore, the overall maximum mechanical stress can be reduced. This is particularly relevant because silicon and gallium nitride have different thermal expansion coefficients. Furthermore, controlling the temperature of gallium nitride islands, for example, by active or passive cooling, can be less complicated than controlling a larger structure. Gallium nitride islands can also be advantageous because heat buildup from multiple devices can be more evenly distributed.

[0021] The gallium nitride HEMT of the transmitting amplifier may be formed within the first gallium nitride island, and the gallium nitride HEMT of the receiving amplifier may be formed within the second gallium nitride island.

[0022] By locating different devices in different physical structures, or islands, the interference of a first device with the operation of a second device can be reduced, which may be understood as, for example, a noisier signal.

[0023] The first gallium nitride islands may have lateral dimensions ranging from 0.1 μm to 10 μm. The second gallium nitride islands may have lateral dimensions ranging from 0.1 μm to 10 μm.

[0024] The gallium nitride structures may have lateral dimensions ranging from 0.1 μm to 10 μm.

[0025] The term "lateral dimension" may refer to a dimension parallel to the planar top surface of a silicon substrate. In terms of a gallium nitride structure or gallium nitride islands, the lateral dimension may be understood as, for example, the diameter or radius of a polygon or circle. Because gallium nitride is often composed of a wurtzite crystal structure, the shape of the gallium nitride structure or gallium nitride island may correspond to a hexagon. Alternatively, the lateral dimension may refer to other dimensions, such as the green length of the structure or island.

[0026] The MMIC front-end module is a silicon-based frequency up-converter electrically connected to a transmit amplifier, the frequency up-converter configured to up-convert a frequency of an outgoing signal transmitted by the MMIC front-end module; a silicon-based frequency downconverter electrically connected to the transmit amplifier, the frequency downconverter configured to downconvert the frequency of an incoming signal received by the MMIC front-end module; The device may further include:

[0027] The terms "frequency downconverter", and indeed "frequency upconverter", may be understood to correspond to an RF mixer. A frequency upconverter may be understood as converting a transmitted oscillator signal from an intermediate frequency (IF) signal to an RF signal. A frequency upconverter may consequently be understood as converting an incoming / received RF signal to an IF signal.

[0028] The integration of gallium nitride and silicon devices presented not only allows the transmit and receive switches to be silicon-based, but also allows the frequency converter to be a silicon-based device.

[0029] The MMIC front-end module may further include an antenna configured to transmit and receive radio signals, the transmit / receive switch being electrically connected to the antenna.

[0030] An antenna may be understood as any component / structure configured or suitable for transmitting and receiving wireless electromagnetic signals. Integrating the antenna close to the MMIC front-end, semiconductor devices, amplifiers, and switches is preferable because it reduces parasitic losses and can miniaturize the overall size of the MMIC front-end module.

[0031] The antenna may be supported by a silicon substrate, which may allow for closer antenna integration.

[0032] The antenna may be an array antenna, which may comprise a plurality of antenna array elements. Antenna arrays allow for beamforming and therefore also allow for leaner and more flexible wireless communications.

[0033] The gallium nitride structure may comprise a vertical nanowire structure arranged perpendicular to the silicon substrate.

[0034] The gallium nitride structure comprises a gallium nitride layer and an Al layer, where 0≦x≦0.95. x Ga 1-x It may have N layers.

[0035] The gallium nitride structure may comprise an aluminum nitride layer.

[0036] Advantages of such gallium nitride structures include improved semiconductor material with high crystalline quality and fewer defects, and gallium nitride structures can be made thinner and require less material for fabrication than structures that use buffer layers.

[0037] The silicon-based transmit / receive switch may be integrally formed in a silicon substrate, or the silicon-based transmit / receive switch may be supported by a silicon substrate.

[0038] As such, tighter integration of components can be achieved. By using an already existing silicon substrate to form silicon-based devices, several manufacturing steps may be removed from the manufacturing process, reducing overall complexity.

[0039] Further scope of applicability of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

[0040] It is therefore to be understood that the invention is not limited to the particular components of the device or acts of the method described, as such devices and methods may vary, and that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0041] It should be noted that, as used in this specification and the appended claims, the words "a," "an," "the," and "said" are intended to mean that there are one or more elements, unless the context clearly dictates otherwise. Thus, for example, reference to a "unit" or "said unit" may include a plurality of devices, etc. Furthermore, the words "comprise," "include," "includes," and similar words do not exclude other elements and steps. [Brief explanation of the drawings]

[0042] These and other aspects of the present invention will now be described in more detail with reference to the accompanying drawings, which should not be construed as limiting, but instead for purposes of illustration and understanding.

[0043] As shown in the drawings, the dimensions of layers and regions may be exaggerated for illustrative purposes and, therefore, are provided to show the general structure. Like reference numbers refer to like elements throughout.

[0044] [Figure 1] Schematic diagram of an MMIC front-end module. [Figure 2] Schematic of an MMIC front-end module with two gallium nitride islands. [Figure 3] Schematic diagram of an MMIC front-end module with frequency up-converters and frequency down-converters. [Figure 4] Schematic diagram of an MMIC front-end module with an antenna. [Figure 5] Schematic cross-section of a gallium nitride structure. [Figure 6] 1 is an exemplary transmit amplifier circuit. [Figure 7] 1 is an exemplary receive amplifier circuit. Detailed Description of the Invention

[0045] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which presently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the invention to those skilled in the art.

[0046] FIG. 1 shows a monolithic microwave integrated circuit (MMIC) front-end module 100.

[0047] The MMIC front-end module 100 comprises a gallium nitride structure 110. The gallium nitride structure 110 is supported by a silicon substrate 120.

[0048] The MMIC front-end module 100 further includes a silicon-based transmit / receive switch 130. The transmit / receive switch 130 has a transmit mode and a receive mode.

[0049] The gallium nitride structures 110 may have lateral dimensions ranging from 0.1 μm to 10 μm. The gallium nitride structures 110 may have a circular or polygonal shape when viewed from the top. The gallium nitride structures 110 may have a hexagonal shape.

[0050] The silicon-based transmit / receive switch 130 may be integrally formed in the silicon substrate 120. The silicon-based transmit / receive switch 130 may be supported by the silicon substrate 120. The silicon-based transmit / receive switch may be formed in an added silicon structure that is not initially part of the silicon substrate 120. Such an added silicon structure may be deposited, for example, by chemical vapor deposition (CVD) or a similar deposition technique.

[0051] The silicon substrate 120 is <111> The silicon substrate 120 may have a flat upper surface with Miller indices of 0.05 to 0.05. The silicon substrate 120 may be a substantially single-crystal silicon substrate. The silicon substrate 120 may be a silicon wafer.

[0052] The MMIC front-end module 100 further includes a transmit amplifier 112 electrically connected 132 to the transmit / receive switch 130. The transmit amplifier 112 may be configured to amplify an outgoing signal transmitted by the MMIC front-end module 100. The transmit amplifier 112 includes a gallium nitride high electron mobility transistor (HEMT) 114 formed within the gallium nitride structure 110. The HEMT 114 may include a source node, a drain node, and a gate node, and a voltage applied to the gate node may affect a current between the source node and the drain node.

[0053] The transmit amplifier 112 may be a PA. The transmit amplifier 112 may be a Class A, B, AB, C, D, E, F, G, or H PA. The transmit amplifier 112 may be a differential amplifier. FIG. 6 shows the circuit of an exemplary transmit amplifier 112, which is a Class E amplifier. The transmit amplifier 112 may be configured to amplify the outgoing signal, for example, by increasing its voltage or current. The transmit amplifier 112 may comprise multiple HEMTs formed in the gallium nitride structure 110.

[0054] The MMIC front-end module 100 further includes a receive amplifier 113 electrically connected (133) to the transmit / receive switch 130. The receive amplifier 113 may be configured to amplify an incoming signal received by the MMIC front-end module 100. The receive amplifier 113 includes a gallium nitride HEMT 115 formed within the gallium nitride structure 110. The HEMT 115 may include a source node, a drain node, and a gate node, and a voltage applied to the gate node may affect a current between the source node and the drain node.

[0055] The receiving amplifier 113 may be an LNA. The receiving amplifier 113 may be a differential amplifier. Figure 7 shows an example circuit of the receiving amplifier 113. The receiving amplifier 113 may be configured to amplify the incoming signal, for example, by increasing its voltage or current. The receiving amplifier 113 may comprise multiple HEMTs formed in the gallium nitride structure 110.

[0056] 1-4, amplifiers 112, 113 are shown as dashed triangles. These should be seen as schematic block representations of amplifiers, while FIGS. 6-7 show exemplary circuits for amplifiers 112, 113.

[0057] 6, the output node (VOUT) corresponds to electrical connection 132. In FIG.

[0058] VIN and VOUT are referred to at the level of an individual amplifier. Therefore, the VIN node in FIG. 6 does not correspond to the VIN node in FIG. 7. For the same reason, the VOUT node in FIG. 6 does not correspond to the VIOUT node in FIG. 7. The drive node (VDD) may be shared or separate for both amplifiers 112 and 113. The VDD node may have or be adapted to have a substantially fixed voltage level. The ground node (GND) may be shared or separate for both amplifiers 112 and 113. The GND node may be understood to be referred to as a relative ground node having a substantially fixed voltage level. The GND node may have a lower voltage level than the VDD node. The bias node (VBIAS) of the example LNA in FIG. 7 may have or be adapted to have a bias voltage level configured to affect the voltage level at the gate node of the HEMT 115. The example circuit is also shown to include resistors, inductors, and capacitors, which may be formed as separate components or as intrinsic parts based on the characteristics of the conductors within the amplifier circuit.

[0059] Setting the transmit / receive switch 130 to the transmit mode may include forming an electrical path from the transmit amplifier 112, via electrical connection 132, through the transmit / receive switch 130, to, for example, an antenna. Setting the transmit / receive switch 130 to the receive mode may include forming an electrical path from the receive amplifier 113, via electrical connection 133, through the transmit / receive switch 130, to, for example, an antenna.

[0060] 2 shows an MMIC front-end module 100 in which a gallium nitride structure 110 supported by a silicon substrate 120 comprises a first gallium nitride island 211 and a second gallium nitride island 212. The first gallium nitride island 211 and the second gallium nitride island 212 are physically spaced apart and laterally co-located on the silicon substrate.

[0061] The gallium nitride HEMT 114 of the transmission amplifier 112 may be formed in the first gallium nitride island 211. The gallium nitride HEMT 115 of the reception amplifier 113 may be formed in the second gallium nitride island 212.

[0062] The first gallium nitride islands 211 may have lateral dimensions ranging from 0.1 μm to 10 μm. The second gallium nitride islands 212 may have lateral dimensions ranging from 0.1 μm to 10 μm. The gallium nitride islands 211, 212 may have a circular or polygonal shape when viewed from the top. The gallium nitride islands 211, 212 may have a hexagonal shape.

[0063] 3 shows MMIC front-end module 100 further comprising a silicon-based frequency upconverter 342 electrically connected 332 to transmit amplifier 112. Frequency upconverter 342 may be configured to upconvert the frequency of an outgoing signal transmitted by MMIC front-end module 100.

[0064] MMIC front-end module 100 may further include a silicon-based frequency downconverter 343 electrically connected 333 to receive amplifier 113. Frequency downconverter 343 may be configured to downconvert the frequency of an incoming signal received by MMIC front-end module 100.

[0065] The frequency up- and down-converters 342, 343 may be mixers. The frequency up- and down-converters 342, 343 may be connected to a local oscillator that outputs a predictable oscillation signal. The frequency up-converter 342 may convert an outgoing signal, which is an IF signal, to a corresponding RF signal. The frequency down-converter 343 may convert an incoming signal, which is an RF signal, to a corresponding IF signal, where IF< <RFである。

[0066] The silicon-based frequency up- and down-converters 342, 343 may be integrally formed in the silicon substrate 120. The silicon-based frequency up- and down-converters 342, 343 may be formed in an additional silicon structure that is not initially part of the silicon substrate 120. Such an additional silicon structure may be deposited, for example, by CVD or a similar deposition technique.

[0067] 4 shows the MMIC front-end module 100 further comprising an antenna 451. The antenna 451 may be configured to transmit and receive radio signals. The transmit / receive switch 130 may be electrically connected (453) to the antenna 451.

[0068] The antenna 451 may be configured to transmit and receive electromagnetic radio signals. The antenna 451 may be configured and optimized to transmit and receive radio signals having frequencies in the range of 10 MHz to 100 GHz, preferably in the range of 24 GHz to 72 GHz.

[0069] The antenna 451 may be a dipole antenna, a monopole antenna, a patch antenna, etc. The antenna 451 may be a multiple input multiple output (MIMO) antenna. The antenna 451 may comprise a perfect electrical conductor (PEC). The antenna 451 may include a metal. The antenna 451 may include a degenerately doped semiconductor, such as silicon. The antenna 451 may include a dielectric material.

[0070] The antenna 451 may be supported by the silicon substrate 120. The antenna 451 may be integrally formed within the silicon substrate 120.

[0071] The antenna 451 may be an array antenna, which comprises a plurality of antenna array elements 455.

[0072] FIG. 5 shows a gallium nitride structure 110 comprising vertical nanowire structures 516 disposed vertically on a silicon substrate 120 .

[0073] The vertical nanowire structure 516 comprises or consists essentially of gallium nitride. The vertical nanowire structure 516 comprises or consists essentially of aluminum nitride. The gallium nitride structure 110 may comprise a plurality of vertical nanowire structures 516. The vertical nanowire structures 516 may be formed on a silicon substrate 120.

[0074] The gallium nitride structure 110 comprises a gallium nitride layer 517 and an AlN layer 518, where 0≦x≦0.95. x Ga 1-x The gallium nitride layer 517 may include an AlN layer 518. x Ga 1-x It may be located on the N layer 518. x Ga 1-x The N layer 518 may laterally and vertically surround the vertical nanowire structure 516 .

[0075] Al x Ga 1-x The N layer 518 can have continuous or discrete grading. Continuous grading means that the Al x Ga 1-x This may be understood as a substantially continuous change in the value of x at different locations in the N layer 518. Similarly, the discrete grading may be understood as a change in the Al x Ga 1-x At different locations in the N layer 518, the value x may be understood to vary by larger discrete steps, for example, −0.2 per step.

[0076] The gallium nitride structure 110 may include an aluminum nitride layer 519. The aluminum nitride layer 519 is formed by vertically extending Al x Ga 1-x It may be located below the N layer 518.

[0077] Gallium nitride structure 110 may further be understood as a "semiconductor layer structure" within the context of European Patent Application No. 19215267.6 as filed. See the text relating to "First Aspect" in the Overview. See also Figures 1-4 and corresponding portions of the specification. The identified subject matter is incorporated herein by reference.

[0078] HEMTs 114, 115 may further be understood as HEMTs in the context of European Patent Application No. 19215267.6, also filed as filed. See the text relating to "Second Aspect" in the Overview. See also Figures 5-6 and corresponding portions of the specification. The identified subject matter is incorporated herein by reference.

[0079] In general, electrical connections 132, 133, 333, 332, 453, and other connections not referenced by numerals, such as connections internal to amplifiers 112, 113, may be understood as any physical connection suitable for carrying electrical current. The connections may be formed as part of conventional back end of line (BEOL) processing for silicon integrated circuits.

[0080] The electrical connections 132, 133, 333, 332, 453 may include metallic materials such as aluminum, copper, palladium, silver, and / or gold, as well as alloys of the aforementioned materials. For example, alloys used for the electrical connections 132, 133, 333, 332, 453 may include aluminum and copper or palladium and gold. The electrical connections 132, 133, 333, 332, 453 may also be implemented as degenerately doped semiconductors, such as silicon.

[0081] A method for forming the MMIC front-end module 100 includes: providing a silicon substrate 120 covered with a gallium nitride layer structure; Etching a gallium nitride structure 110 or a plurality of gallium nitride islands 211, 212 from the gallium nitride layer structure; depositing a polycrystalline silicon structure on the silicon substrate 120, optionally by CVD; forming silicon-based devices 130, 342, 343 in a silicon substrate 120 or deposited polycrystalline silicon structure; forming gallium nitride HEMT devices 114, 115 within the gallium nitride structure 110 or the plurality of gallium nitride islands 211, 212; forming metal layers, vias, and interconnects to connect the silicon-based device 130, 342, 343 and the gallium nitride HEMT device; passivating the MMIC front-end module 100 described above, for example by deposition; may include:

[0082] The MMIC front-end module 100 is a 5G NR (5th Generation Radio) thThe MMIC front-end module 100 may be configured for Bluetooth communications. The MMIC front-end module 100 may be part of a network interconnection point, such as a wireless base station. The MMIC front-end module 100 may be part of a network device, such as a mobile device, a computer, or an Internet of Things (IoT) device. Those skilled in the art will appreciate that the present invention is not limited to only the above examples. The MMIC front-end module 100 may be configured for frequencies in the range of 10 MHz to 100 GHz, preferably in the range of 24 GHz to 72 GHz. Alternatively, when the MMIC front-end module 100 is configured for Bluetooth communications, the MMIC front-end module 100 may be configured for frequencies in the range of 1 GHz to 3 GHz, preferably in the range of 2.4 GHz to 2.5 GHz.

[0083] Additionally, variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

Claims

1. A monolithic microwave integrated circuit (MMIC) front-end module (100), comprising: a gallium nitride structure (110) supported by a silicon substrate (120), the gallium nitride structure comprising a first gallium nitride island (211) and a second gallium nitride island (212), the first gallium nitride island and the second gallium nitride island being physically spaced apart and laterally co-located on the silicon substrate; a silicon-based transmit / receive switch (130) having a transmit mode and a receive mode; a transmit amplifier (112) configured to amplify an outgoing signal transmitted by the MMIC front-end module, the transmit amplifier being electrically connected (132) to the transmit / receive switch, the transmit amplifier comprising a gallium nitride high electron mobility transistor (HEMT) (114) formed within the gallium nitride structure; a receive amplifier (113) configured to amplify an incoming signal received by the MMIC front-end module, the receive amplifier being electrically connected to the transmit / receive switch (133), the receive amplifier comprising a gallium nitride HEMT (115) formed within the gallium nitride structure; An MMIC front-end module comprising:

2. 2. The MMIC front-end module of claim 1, wherein the transmit amplifier comprises a plurality of HEMTs formed within the gallium nitride structure.

3. 3. The MMIC front-end module of claim 1, wherein the receiving amplifier comprises a plurality of HEMTs formed within the gallium nitride structure.

4. a silicon-based frequency upconverter (342) electrically connected (332) to the transmit amplifier (112), the frequency upconverter (342) being configured to upconvert the frequency of an outgoing signal transmitted by the MMIC front-end module; a silicon-based frequency downconverter (343) electrically connected (333) to the receiving amplifier (113), the frequency downconverter (343) being configured to downconvert the frequency of an incoming signal received by the MMIC front-end module; 4. The MMIC front-end module according to claim 1, comprising:

5. 2. The MMIC front-end module of claim 1, wherein the gallium nitride HEMT of the transmitting amplifier is formed on the first gallium nitride island, and the gallium nitride HEMT of the receiving amplifier is formed on the second gallium nitride island.

6. 6. The MMIC front-end module of claim 1, wherein the first gallium nitride island and the second gallium nitride island have lateral dimensions in the range of 0.1 [mu]m to 10 [mu]m.

7. The MMIC front-end module of any one of claims 1 to 6, wherein the gallium nitride structure has lateral dimensions in the range of 0.1 μm to 10 μm.

8. 8. The MMIC front-end module of claim 1, further comprising an antenna (451) configured to transmit and receive radio signals, the transmit / receive switch being electrically connected to the antenna (453).

9. 9. The MMIC front-end module of claim 8, wherein the antenna is supported by the silicon substrate.

10. 10. The MMIC front-end module of claim 8 or 9, wherein the antenna is an array antenna, the array antenna comprising a plurality of antenna array elements (455).

11. 11. The MMIC front-end module of claim 1, wherein the gallium nitride structure comprises a vertical nanowire structure arranged perpendicular to the silicon substrate.

12. The MMIC front-end module of any one of claims 1 to 11, wherein the gallium nitride structure comprises a gallium nitride layer (517) and an AlxGa1-xN layer (518), with 0≦x≦0.

95.

13. An MMIC front-end module according to any one of claims 1 to 12, wherein the gallium nitride structure comprises an aluminum nitride layer (519).

14. 14. The MMIC front-end module according to claim 1, wherein the silicon-based transmit / receive switch is integrally formed with or supported by the silicon substrate.

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