A terahertz resonant tunneling diode radiation source integrated with a back cavity patch antenna

Abstract

The application discloses a terahertz resonant tunneling diode radiation source integrated with a back cavity patch antenna, and belongs to the technical field of terahertz wireless transceiving, comprising a substrate, an RTD, a back cavity patch antenna, a GSG direct current bias line and two stable resistors which are located above the substrate; the back cavity patch antenna comprises a back cavity bottom reference ground, a back cavity metal sidewall, a back cavity passivation layer, a patch feed line, a radiation patch and a back cavity top reference ground; the RTD and the GSG direct current bias line are located above the back cavity patch antenna, the radiation patch is connected to the radio frequency side of the RTD through the patch feed line, and the GSG direct current bias line is connected to the direct current side of the RTD. The application utilizes the resonance of the RTD and the back cavity patch antenna to excite a terahertz oscillation signal, the terahertz oscillation signal is enhanced through the integrated back cavity resonance, high-gain radiation on the air side is realized through the radiation patch, and the loss of the terahertz wave on the substrate side can be effectively reduced; compared with the traditional mode of loading a Si lens on the substrate side, the integrated back cavity structure has the advantages of miniaturization and low profile, and can meet the application requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of terahertz wireless transceiver, and in particular relates to a terahertz resonant tunneling diode radiation source integrated with a cavity-backed patch antenna. Background Art

[0002] Terahertz waves, located between microwaves and infrared, possess narrow beams, wide bandwidth, strong penetration, and low energy, making them ideally suited for monolithic integration of wireless communications and wireless sensing. By organically combining sensing and communication functions, terahertz technology promotes and enhances each other, further advancing the realization of the "Internet of Everything." As a cutting-edge technology, terahertz technology has far-reaching implications for basic scientific research, national economic development, and national defense, playing an indispensable role in future 6G communications. Terahertz wave sources are the cornerstone of terahertz technology research and a core component of terahertz application systems. The development of high-power, high-efficiency, room-temperature-operating, bandwidth-adjustable terahertz radiation sources has always been a key focus and research hotspot for scientists.

[0003] In recent years, terahertz radiation sources based on resonant tunneling diodes (RTDs) as nonlinear devices have attracted widespread attention from researchers due to their small size, light weight, easy integration, room temperature operation, and low power consumption, opening up new technical avenues for the application of terahertz technology.

[0004] At present, the RTD-based oscillators (RTD Oscillator, RTO) reported at home and abroad are mainly based on the InP material system, and the integrated antenna forms used mainly include slot antennas (such as Chinese patent No. 202110707842.0: A resonant tunneling diode terahertz oscillator and its circuit structure, Chinese patent No. 202410614915.5: A resonant tunneling diode oscillator and terahertz radiation source device, and Chinese patent No. 201610877332.7: Detuned fed slot antenna RTO terahertz wave source and manufacturing process), bow tie antennas (such as Chinese patent No. 20210707698.0: A resonant tunneling diode terahertz oscillator source, and the journal article with index number DOI:10.11972 / j.issn.1001-9014.2022.02.010 "Design and realization of InP-based resonant tunneling diode THz oscillator”), and patch antennas (such as Chinese patent No. 202310087308.3: resonant tunneling diode, oscillator and detection system).

[0005] Although the above-mentioned form of antenna can be integrated with the RTD monolithically to realize on-chip RTO, there are still the following problems: (1) the antenna gain is low, it is not easy to realize higher radiation power, which is not conducive to the application of RTO in actual 6G communication system; (2) the antenna radiation direction is easy to be directed to the substrate side, which will increase the terahertz wave loss in the substrate, which is not conducive to realizing high DC-to-RF conversion efficiency; (3) generally, the way of loading Si lens on the substrate side is adopted to enhance the radiation gain, but the size of the Si lens is generally much larger than the size of the RTO itself, and is mostly a half-elliptical lens or a half-spherical lens, which occupies a larger transverse and longitudinal area, which is not conducive to realizing low profile and miniaturization. SUMMARY

[0006] In view of the problems existing in the existing integrated antenna form, the present application provides a terahertz resonant tunneling diode radiation source integrated with a back cavity patch antenna, which realizes resonant enhancement of terahertz oscillation signals by integrating a back cavity structure with the patch antenna, and realizes high-gain radiation towards the air side, with the characteristics of high-gain radiation, low substrate loss, low profile and miniaturization.

[0007] The technical scheme adopted by the present application is as follows:

[0008] A terahertz resonant tunneling diode radiation source integrated with a back cavity patch antenna, comprising a substrate, and a resonant tunneling diode (RTD), a back cavity patch antenna, a GSG DC bias line and two stabilizing resistors located above the substrate;

[0009] The back cavity patch antenna comprises a back cavity bottom reference ground, a back cavity metal sidewall, a back cavity passivation layer, a patch feed line, a radiation patch and a back cavity top reference ground;

[0010] Among them, the RTD and the back cavity bottom reference ground are located on the upper surface of the substrate; the back cavity passivation layer is located on the upper surface of the back cavity bottom reference ground; the back cavity metal sidewall is located inside the back cavity passivation layer and has an open ring structure; the patch feed line, the radiation patch, the back cavity top reference ground and the GSG DC bias line are all located on the upper surface of the back cavity passivation layer; the radiation patch is connected to the patch feed line, and the radiation patch is specifically located in the inner region of the ring structure of the back cavity metal sidewall, and the patch feed line is specifically located in the open side region of the back cavity metal sidewall; the patch feed line is connected to the radio frequency side of the RTD, and the GSG DC bias line is connected to the DC side of the RTD; the back cavity top reference ground is arranged around the patch feed line, the radiation patch and the RTD, and has a gap between the patch feed line and the radiation patch, and forms an ohmic contact with the RTD; the two ground wires (G wires) of the GSG DC bias line are connected to the back cavity top reference ground; the two stabilizing resistors are respectively located in the gap between the ground wire and the signal wire of the GSG DC bias line, and are close to the connection end of the GSG DC bias line and the RTD; the bottom end of the back cavity metal sidewall is connected to the back cavity bottom reference ground, and the top end is connected to the back cavity top reference ground.

[0011] Furthermore, the RTD includes, from bottom to top, an emitter, an emitter isolation layer, an emitter potential barrier, a potential well layer, a collector potential barrier, a collector isolation layer, a collector and a collector top metal layer.

[0012] Furthermore, the patch feed line is connected to the top metal layer of the collector.

[0013] Furthermore, the signal line (S line) of the GSG DC bias line is connected to the collector top metal layer.

[0014] Furthermore, the reference ground portion at the top of the back cavity is located on the upper surface of the extension layer of the emitter, and forms an ohmic contact with the extension layer of the emitter.

[0015] Furthermore, the material of the stabilizing resistor is nickel-chromium alloy (Ni-Cr) or tantalum nitride (Ta-N).

[0016] Furthermore, an RTD passivation layer is provided between the collector and the collector top metal layer. The RTD passivation layer extends around the RTD to protect and isolate the RTD. A through hole is provided inside the RTD passivation layer to achieve connection between the collector and the collector top metal layer.

[0017] Furthermore, the material of the RTD passivation layer and the back cavity passivation layer is SiO2, SiN (Si3N4), SiON or BCB (benzocyclobuten).

[0018] Furthermore, the RTD is an InP-based RTD or a GaN-based RTD.

[0019] Furthermore, when the RTD is an InP-based RTD, the substrate is InP and the RTD epitaxial is In x Ga 1-x As / AlAs material system, 0 <x<1。

[0020] Furthermore, when the RTD is a GaN-based RTD, the substrate is GaN, and the RTD epitaxy is an AlGaN / GaN material system.

[0021] Furthermore, the radiation patch is a rectangular patch antenna or a bow tie patch antenna.

[0022] Furthermore, when the radiation patch is a bowtie patch antenna, a hollow dual antenna structure is specifically adopted, and the patch feed line is connected to the feed line end of the hollow dual antenna structure.

[0023] Furthermore, the metal sidewall of the back cavity adopts a metal wall structure or a metal column structure.

[0024] The beneficial effects of the present invention are:

[0025] 1. This invention proposes a terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna. The terahertz oscillation signal is excited by the resonance of the RTD and the cavity-backed patch antenna. After the integrated cavity resonance is enhanced, high-gain radiation on the air side is achieved through the radiating patch.

[0026] 2. The present invention achieves resonance enhancement and air-side radiation by designing a cavity-backed patch antenna, thereby effectively reducing the loss of terahertz waves on the substrate side. Specifically, a cavity-backed patch antenna is integrated around the patch antenna to form a resonant microcavity, thereby enhancing the terahertz waves radiated by the patch antenna. At the same time, due to the presence of the cavity-backed patch antenna, the direction of terahertz wave radiation from the patch antenna is directed toward the air side, thereby effectively reducing the substrate dielectric loss caused by the terahertz wave radiation toward the substrate side.

[0027] 3. Compared with the traditional method of loading Si lens on the substrate side to enhance radiation gain, the integrated back cavity structure of the present invention has the advantages of miniaturization and low profile, which can meet application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The tape-out layout of the terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna provided in Example 1 of the present invention;

[0029] Figure 2 A cross-sectional view of a terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna provided in Example 1 of the present invention;

[0030] Figure 3 A 3D view of the terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna provided in Example 1 of the present invention;

[0031] Figure 4 Schematic diagram of the structure of the RTD in Example 1 of the present invention;

[0032] Figure 5 This is an equivalent circuit diagram of a terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna provided in Example 1 of the present invention;

[0033] Figure 6 The resonance characteristic curve of the terahertz resonant tunneling diode radiation source of the integrated cavity-backed patch antenna provided in Example 1 of the present invention;

[0034] Figure 7 The radiation gain curve of the terahertz resonant tunneling diode radiation source of the integrated cavity-backed patch antenna provided in Example 1 of the present invention;

[0035] Figure 8The tape-out layout of the terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna provided in Example 2 of the present invention;

[0036] Figure 9 Schematic diagram of the structure of RTD in Example 3 of the present invention;

[0037] The descriptions of the symbols in the accompanying drawings are as follows:

[0038] 1: Substrate; 2: RTD; 3: Back cavity bottom reference ground; 4: Back cavity metal sidewall; 5: Back cavity passivation layer; 6: Patch feed line; 7: Radiating patch; 8: Back cavity top reference ground; 9: GSG DC bias line; 10: Stabilizing resistor; 11: RTD nonlinear large / small signal model; 12: First circuit structure; 13: Second circuit structure; 14: Coplanar waveguide inductor L CPW ; 15: DC-RF bias-tee structure; 16: spectrum analyzer. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna, the structure of which is as follows: Figure 1 、 Figure 2 and Figure 3 As shown, it includes a substrate 1, and an RTD 2, a cavity-backed patch antenna, a GSG DC bias line 9 and two stabilizing resistors 10 located above the substrate 1.

[0043] The cavity-backed patch antenna includes a cavity-backed bottom reference ground 3, a cavity-backed metal sidewall 4, a cavity-backed passivation layer 5, a patch feed line 6, a radiation patch 7 and a cavity-backed top reference ground 8.

[0044] The structure of RTD2 is as follows Figure 4As shown, it includes, from bottom to top, an emitter, an emitter isolation layer, an emitter potential barrier, a potential well layer, a collector potential barrier, a collector isolation layer, a collector and a collector top metal layer.

[0045] Among them, RTD2 and the back cavity bottom reference ground 3 are located on the upper surface of the substrate 1; the back cavity passivation layer 5 is located on the upper surface of the back cavity bottom reference ground 3; the back cavity metal side wall 4 is located inside the back cavity passivation layer 5, and is an open square ring structure; the patch feed line 6, the radiation patch 7, the back cavity top reference ground 8 and the GSG DC bias line 9 are all located on the upper surface of the back cavity passivation layer 5; the radiation patch 7 is connected to the patch feed line 6; the radiation patch 7 is specifically a rectangular patch antenna, which is located in the inner area of ​​the square ring structure of the back cavity metal side wall 4; the patch feed line 6 is specifically located in the open side area of ​​the back cavity metal side wall 4; the patch feed line 6 is connected to the collector top metal layer of RTD2, and the signal line (S line) of the GSG DC bias line 9 is connected to The top metal layer of the collector of RTD2; the back cavity top reference ground 8 is set around the patch feed line 6, the radiation patch 7 and RTD2, and a gap is left between the patch feed line 6 and the radiation patch 7. The back cavity top reference ground 8 is partially located on the upper surface of the extension layer of the emitter of RTD2, forming an ohmic contact with the extension layer of the emitter; the two ground lines (G lines) of the GSG DC bias line 9 are connected to the back cavity top reference ground 8; the two stabilizing resistors 10 are respectively located in the gap between the ground line and the signal line in the GSG DC bias line 9, and are close to the connection end of the GSG DC bias line 9 and RTD2; the bottom end of the back cavity metal side wall 4 is connected to the back cavity bottom reference ground 3, and the top end is connected to the back cavity top reference ground 8.

[0046] The materials used in each structure of this embodiment are as follows:

[0047] The substrate 1 is made of semi-insulating (SI) InP material.

[0048] The RTD2 is an InP-based RTD, and the epitaxial wafer of RTD2 is prepared by a molecular beam epitaxy (MBE) process, including the preparation of an emitter, an emitter isolation layer, an emitter barrier, a potential well layer, a collector barrier, a collector isolation layer and a collector from bottom to top. Then, a collector top metal layer is evaporated on the epitaxial wafer, and the collector top metal layer is used as a mask to expose the RTD2 structure by wet etching and photolithography. The etching is stopped when the emitter is etched, and a resist is coated on the upper surface of the emitter. The wet etching is continued until the upper surface of the substrate 1 to obtain an emitter extension layer. The resist is stripped by a wet stripping process, and the surface is cleaned to obtain RTD2; wherein, the emitter adopts a heavily doped layer (n++ / n+)In 0.53 Ga 0.47As; the emitter isolation layer uses unintentional doped (UID) In 0.53 Ga 0.47 As, thickness is 5nm; emitter barrier, potential well layer and collector barrier adopt UID's In 0.8 Ga 0.2 As / AlAs / In 0.8 Ga 0.2 As heterojunction, thickness 1.2 / 4.5 / 1.2nm; collector isolation layer uses UID's In 0.53 Ga 0.47 As, thickness 5nm; collector uses heavily doped layer (n+ / n++)In 0.53 Ga 0.47 As; the collector top metal layer adopts Ti / Pd / Au metal system; preferably, the emitter and collector surfaces are further heavily doped to obtain corresponding contact layers, and the doping concentration of the obtained emitter contact layer and collector contact layer is 3×10 19 cm -3 , the doping concentration of the emitter and collector is 3×10 18 cm -3 , the thickness of the emitter contact layer is 400nm, the thickness of the emitter is 25nm, the thickness of the collector is 25nm, and the thickness of the collector contact layer is 10nm.

[0049] The material of the back cavity passivation layer 5 is SiO 2 .

[0050] The material of the stabilizing resistor 10 is nickel-chromium alloy.

[0051] The materials of the back cavity bottom reference ground 3, back cavity metal side wall 4, patch feed line 6, radiation patch 7, back cavity top reference ground 8 and GSG DC bias line 9 are Au; among which, the back cavity metal side wall 4 adopts a metal wall structure.

[0052] The process flow of the terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna proposed in this embodiment is as follows:

[0053] Step 1: epitaxially prepare an emitter, an emitter isolation layer, an emitter barrier, a potential well layer, a collector barrier, a collector isolation layer and a collector on the surface of substrate 1 in sequence by molecular beam epitaxy to obtain an epitaxial wafer required for RTD2 etching;

[0054] Step 2: Using an electron beam evaporation process, the RTD2 region is precisely located on the upper surface of the epitaxial wafer, and the collector top metal layer is uniformly evaporated on the upper surface of the epitaxial wafer; using a wet etching process, using the collector top metal layer as a mask, the epitaxial material is etched until the upper surface of the emitter material of RTD2;

[0055] Step 3: Using a photolithography process, uniformly coating the exposed upper surface of the emitter material with photoresist, exposing and developing to obtain an extended layer region of the emitter, and using a wet etching process to etch the emitter material outside the photoresist, thereby forming an emitter with an extended layer; further etching the substrate 1 until the depth of the back cavity bottom reference ground 3 required on the upper surface of the substrate 1 is reached, and using an electron beam evaporation process to sputter a metal layer on the etched upper surface of the substrate 1 to obtain the back cavity bottom reference ground 3;

[0056] Step 4: Using a photolithography process, a photoresist is coated on the upper surface of the reference ground 3 at the bottom of the back cavity. The mask of the metal wall structure is accurately aligned with the surface of the photoresist coating. Then, an exposure process is used to project the mask pattern onto the photoresist surface to complete the mask lithography to form a photoetching groove. The metal is sputtered into the photoetching groove by an electron beam evaporation process to form the metal sidewall 4 of the back cavity. Finally, a wet removal process is used to strip the photoresist.

[0057] Step 5: Using plasma enhanced chemical vapor deposition technology, a passivation layer is deposited on the reference ground 3 at the bottom of the back cavity and the surface of the back cavity metal sidewall 4, with the deposition thickness reaching the bottom of the emitter of RTD2 to obtain a back cavity passivation layer 5;

[0058] Step 6: Using electron beam evaporation technology, a metal layer is uniformly sputtered on the upper surface of the back cavity passivation layer 5, and interconnected with the top metal layer of the collector of RTD2 to obtain a patch feeder 6;

[0059] Step 7: Using an electron beam evaporation process, a metal layer is uniformly sputtered on the upper surface of the back cavity passivation layer 5, and interconnected with the patch feeder 6 to obtain a radiation patch 7;

[0060] Step 8: Using electron beam evaporation technology, a metal layer is uniformly sputtered on the upper surface of the back cavity passivation layer 5 to form a semi-open ring metal layer surrounding the patch feed line 6 and the radiation patch 7. The metal layer at the open end is evaporated to the upper surface of the extension layer of the emitter of RTD2 to form an ohmic contact with it, thereby obtaining the reference ground 8 at the top of the back cavity;

[0061] Step 9: Using an electron beam evaporation process, a metal layer is uniformly sputtered on the upper surface of the back cavity passivation layer 5 to obtain a GSG DC bias line 9, wherein the signal line is interconnected with the top metal layer of the collector of RTD2, and the ground line is interconnected with the reference ground 8 at the top of the back cavity;

[0062] Step 10: Use a thin film sputtering or evaporation deposition process to deposit a thin film material at one end of the interconnection position between the GSG DC bias line 9 and the RTD2. The deposition area is inside the groove formed by the signal line and the ground line of the GSG DC bias line 9 to obtain a stable resistor 10, thereby completing the preparation of the terahertz resonant tunneling diode radiation source with an integrated back-cavity patch antenna.

[0063] The working principle of the terahertz resonant tunneling diode radiation source with an integrated back-cavity patch antenna proposed in this embodiment is: by applying a bias voltage to the GSG DC bias line 9, RTD2 is made to operate in the negative differential resistance region. The negative differential resistance can compensate for the loss of the back-cavity patch antenna, thereby forming energy transfer between the back-cavity patch antenna and the loop of RTD2, generating an oscillation signal, and realizing radiation through the back-cavity patch antenna.

[0064] The equivalent circuit of the terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna proposed in this embodiment is as follows: Figure 5 As shown, the RTD2 is represented as an RTD nonlinear large / small signal model 11; the patch feed line 6 and the radiation patch 7 are equivalent to a first circuit structure 12, including the equivalent capacitance C of the radiation patch 7 to the reference ground 8 at the top of the back cavity ant. , the equivalent inductance L of the radiating patch 7 ant. And the radiation conductance G of the radiation patch 7 to the air side ant. The back cavity bottom reference ground 3, the back cavity metal sidewall 4 and the back cavity passivation layer 5 are equivalent to the second circuit structure 13, including the equivalent capacitance C of the radiation patch 7 to the back cavity bottom reference ground 3 backcav. , the loss conductance G of the back cavity passivation layer 5 backcav. And the equivalent inductance L of the back cavity metal side wall 4 backcav. The GSG DC bias line 9 is equivalent to the coplanar waveguide inductor L CPW 14; DC-RF bias-tee structure 15 is used for feeding and RF testing, and the RF signal is analyzed by spectrum analyzer 16, where V bias represents the bias supply voltage, R bias Represents the bias supply resistor.

[0065] The input admittance Y of the cascade connection of the first circuit structure 12 and the second circuit structure 13 passive Expressed as:

[0066]

[0067] The above formula can be simplified as:

[0068] Y passive =Y ant. +Y backcav. #(2)

[0069] Where Y ant. represents the input admittance of radiating patch 7, Y backcav. represents the input admittance of the back cavity, which includes:

[0070]

[0071] Among them, G ant.represents the real part of the input admittance of the radiation patch 7, B ant. represents the imaginary part of the input admittance of the radiating patch 7, G backcav. represents the real part of the back cavity input admittance, B backcav. represents the imaginary part of the back cavity input admittance.

[0072] and then, Figure 5 The input admittance Y shown in for:

[0073]

[0074] The RTO circuit oscillation conditions are:

[0075]

[0076] The RTO output power is:

[0077]

[0078] Where G passive Indicates Y passive The real part of , that is:

[0079] G passive =G ant. +G backcav. #(7)

[0080] In particular, the resonant tunneling diode radiation source of the integrated cavity-backed patch antenna provided in this embodiment can generate greater output power than the radiation source of the integrated resonant tunneling diode of the ordinary patch antenna. This is because the output power of the radiation source of the integrated resonant tunneling diode of the ordinary patch antenna can be expressed as:

[0081]

[0082] Combining equations (6) and (8), we can see that:

[0083]

[0084] Furthermore, the output power of the resonant tunneling diode radiation source of the integrated back cavity patch antenna provided in this embodiment is greater than that of the radiation source of the integrated resonant tunneling diode of the ordinary patch antenna, which is mainly due to the real part of the input admittance G of the back cavity integrated in the former. backcav. The enhancement of the RTO output power indicates that high-gain radiation can be achieved through the integrated back-cavity resonance enhancement.

[0085] The resonance characteristic curve of the terahertz resonant tunneling diode radiation source of the integrated cavity-backed patch antenna provided in this embodiment is as follows: Figure 6As shown in the figure, it can be seen that in the frequency band of 325~410GHz, the terahertz resonant tunneling diode radiation source of the integrated cavity-backed patch antenna oscillates at 365GHz. At this time, the imaginary part of the input admittance of the entire RTO circuit is im{Y 11}=0; the radiation gain curve is as follows Figure 7 As shown in the figure, the terahertz wave radiation direction of the terahertz resonant tunneling diode radiation source of the obtained integrated back-cavity patch antenna at 365GHz is the air side. The maximum radiation gain shown at the "★" position in the figure is 4.06dBi, which can effectively reduce the substrate dielectric loss caused by the radiation of the terahertz wave to the substrate side.

[0086] This embodiment integrates a back cavity structure into the patch antenna to achieve resonance enhancement of the terahertz oscillation signal and realizes high-gain radiation facing the air side. It has the characteristics of high-gain radiation, low substrate loss, low profile and miniaturization.

[0087] Example 2

[0088] This embodiment provides a resonant tunneling diode radiation source with an integrated cavity-backed patch antenna, the structure of which is as follows: Figure 8 As shown, compared with Example 1, the structural difference is only that the structure of the radiation patch 7 is adjusted to a bowtie patch antenna, specifically a hollow dual antenna structure is adopted, and at this time the patch feed line 6 is connected to the feeder end of the hollow dual antenna structure.

[0089] The process implementation method of the bowtie patch antenna is as follows: first, photoresist is coated on the upper surface of the back cavity passivation layer 5, and a bowtie patch antenna pattern is formed by exposure through a bowtie structure mask; then, an electron beam evaporation process is used to sputter a metal layer around the bowtie patch antenna photoresist pattern to form a back cavity top reference ground 8, and a semi-open ring metal layer is formed around the bowtie patch antenna photoresist pattern and the patch feed line 6, and the metal layer at the open end is evaporated to the upper surface of the collector of RTD2 to form an ohmic contact with it. After removing the photoresist, the bowtie patch antenna and the back cavity top reference ground 8 are obtained.

[0090] Other structures and working principles are the same as those in Example 1.

[0091] Example 3

[0092] This embodiment provides a resonant tunneling diode radiation source with an integrated cavity-backed patch antenna. The only difference from the first embodiment is that the material of the substrate 1 is adjusted to GaN, and the RTD2 is made of Figure 9 In the structure shown, the RTD epitaxy is an AlGaN / GaN material system; other structures and working principles are the same as those in Example 1.

[0093] Example 4

[0094] This embodiment provides a resonant tunneling diode radiation source with an integrated cavity-backed patch antenna. The only difference from the embodiment 2 is that the material of the substrate 1 is adjusted to GaN, and RTD2 is made of Figure 9 In the structure shown, the RTD epitaxy is an AlGaN / GaN material system; other structures and working principles are the same as those in Example 2.

[0095] The above embodiments only illustrate the principles and advantages of the present invention, and are not intended to limit the present invention. They are only for helping to understand the principles of the present invention. The scope of protection of the present invention is not limited to the above configurations and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the disclosed technology without departing from the essence of the present invention, but they are still within the scope of protection of the present invention.

Claims

1. A terahertz resonant tunneling diode radiation source with an integrated cavity-backed patch antenna, characterized in that: It includes a substrate, an RTD, a cavity-backed patch antenna, a GSG DC bias line, and two stabilizing resistors located above the substrate; The cavity-backed patch antenna comprises a cavity-backed bottom reference ground, a cavity-backed metal sidewall, a cavity-backed passivation layer, a patch feed line, a radiation patch, and a cavity-backed top reference ground; Among them, the RTD and the back cavity bottom reference ground are located on the upper surface of the substrate; the back cavity passivation layer is located on the upper surface of the back cavity bottom reference ground; the back cavity metal side wall is located inside the back cavity passivation layer and is an open ring structure; the patch feed line, radiation patch, back cavity top reference ground and GSG DC bias line are all located on the upper surface of the back cavity passivation layer; the radiation patch is connected to the patch feed line, the radiation patch is specifically located in the inner area of ​​the ring structure of the back cavity metal side wall, and the patch feed line is specifically located in the open side area of ​​the back cavity metal side wall; the patch feed line is connected to the RF side of the RTD, and the GSG DC bias line is connected to the RF side of the RTD. The DC bias line is connected to the DC side of the RTD; the reference ground at the top of the back cavity is set around the patch feed line, the radiating patch and the RTD, and a gap is left between the patch feed line and the radiating patch to form an ohmic contact with the RTD; the two ground lines of the GSG DC bias line are connected to the reference ground at the top of the back cavity; the two stabilizing resistors are respectively located in the gap between the ground line and the signal line in the GSG DC bias line, and close to the connection end of the GSG DC bias line and the RTD; the bottom end of the metal side wall of the back cavity is connected to the reference ground at the bottom of the back cavity, and the top end is connected to the reference ground at the top of the back cavity.

2. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to claim 1, characterized in that: The RTD includes, from bottom to top, an emitter, an emitter isolation layer, an emitter potential barrier, a potential well layer, a collector potential barrier, a collector isolation layer, a collector and a collector top metal layer.

3. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to claim 2, characterized in that: The patch feed line is connected to the collector top metal layer.

4. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to claim 2, characterized in that: The signal line of the GSG DC bias line is connected to the collector top metal layer.

5. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to claim 2, characterized in that: The reference ground portion at the top of the back cavity is located on the upper surface of the extension layer of the emitter and forms an ohmic contact with the extension layer of the emitter.

6. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to any one of claims 1 to 5, characterized in that: An RTD passivation layer is set between the collector and the collector top metal layer. The RTD passivation layer extends around the RTD to protect and isolate the RTD. A through hole is set inside the RTD passivation layer to achieve connection between the collector and the collector top metal layer.

7. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to claim 6, characterized in that: The material of the stabilizing resistor is nickel-chromium alloy or tantalum nitride, and the materials of the RTD passivation layer and the back cavity passivation layer are SiO2, Si3N4, SiON or BCB.

8. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to any one of claims 1 to 5, characterized in that: The RTD is an InP-based RTD or a GaN-based RTD; when the RTD is an InP-based RTD, the substrate is InP and the RTD epitaxial is In x Ga 1-x As / AlAs material system; when the RTD is a GaN-based RTD, the substrate is GaN, and the RTD epitaxy is an AlGaN / GaN material system.

9. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to any one of claims 1 to 5, characterized in that: The radiating patch is a rectangular patch antenna or a bow tie patch antenna. When the radiating patch is a bow tie patch antenna, a hollow dual antenna structure is specifically adopted. At this time, the patch feed line is connected to the feed line end of the hollow dual antenna structure.

10. The terahertz resonant tunneling diode radiation source with integrated cavity-backed patch antenna according to any one of claims 1 to 5, characterized in that: The metal sidewall of the back cavity adopts a metal wall structure or a metal column structure.

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