Terahertz radiation source device and system

Abstract

The invention discloses a terahertz radiation source device and system. The terahertz radiation source device comprises a substrate; the barrier layer is stacked on the substrate; the channel layer is stacked on the barrier layer, and two-dimensional electron gas is generated in the channel layer above the interface of the barrier layer and the channel layer; the source electrode, the drain electrode and the grid electrode are arranged on the channel layer, the source electrode and the drain electrode are distributed on the two sides of the grid electrode, and the source electrode and the drain electrode are electrically connected with two-dimensional electron gas. Two-dimensional electron gas is electrically connected with the source electrode and the drain electrode through the channel layer, ohmic contact resistance can be reduced, saturation current can be increased, energy conversion efficiency can be improved, and output power can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a terahertz radiation source device and system. Background Art

[0002] Terahertz waves refer to electromagnetic waves with frequencies between 0.1 and 10 THz (between millimeter waves and infrared light), representing a virtually untapped frequency band. In recent years, advances in photonics and nanotechnology have enabled the application of terahertz research in a wider range of fields. Today, the application range of terahertz technology is increasingly broad, encompassing areas such as information and communications technology, biology and medicine, nondestructive evaluation, homeland security, food and agricultural product quality control, global environmental monitoring, and ultra-high-speed computing. Furthermore, techniques such as terahertz time-domain spectroscopy, terahertz imaging, and the generation of high-power terahertz waves through nonlinear effects are far superior to traditional tools for analyzing various materials.

[0003] Currently, terahertz radiation sources primarily include electronic and photonic sources. Electronic terahertz source devices include Gunn diodes, resonant tunneling diodes, avalanche transition diodes, vacuum tubes, and solid-state frequency-doubling chain sources. Photonic terahertz source devices include gas lasers based on the rotational energy levels of gas molecules, free electron lasers, and terahertz radiation sources based on ultrafast laser pulses and nonlinear optical crystals. While these solutions hold great promise for application, their bulk, high power consumption, high cost, and ultracold operation make their miniaturization and commercialization difficult.

[0004] Towards the development of miniaturized, low-cost, and cooling-free terahertz radiation sources, research on generating terahertz radiation based on plasma wave instability has gradually attracted the attention of many scientific researchers. The existing technology proposes to use the collective oscillation of the two-dimensional electron gas in the field effect transistor (FET) to generate plasma waves, and the speed of plasma waves can reach 10 6 The speed is on the order of m / s, which is one order of magnitude higher than the speed of a single electron. Therefore, by setting specific boundary conditions, it is possible to produce plasma waves that become unstable and oscillate at frequencies that just cover the terahertz band.

[0005] Prior research on GaN-based high electron mobility transistor (HEMT) terahertz radiation source devices has been based on GaN HEMTs with a Ga-polar surface. For example, Chinese patent publication number CN102239609A proposes a structural design that periodizes the metal in the ohmic contact region of a GaN HEMT with a Ga-polar surface.

[0006] However, even with the existing technology of generating terahertz radiation using plasma waves at room temperature, problems such as low energy conversion efficiency and weak radiation power still exist, which are still insufficient for existing terahertz applications. Therefore, in order to realize commercial terahertz radiation source devices, it is necessary to further improve energy conversion efficiency and increase output power.

[0007] Therefore, in order to solve the above technical problems, it is necessary to provide a terahertz radiation source device and system. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide a terahertz radiation source device and system to reduce ohmic contact resistance, increase saturation current, improve energy conversion efficiency, and increase output power.

[0009] In order to achieve the above object, a specific embodiment of the present invention provides the following technical solutions:

[0010] A terahertz radiation source device, comprising:

[0011] substrate;

[0012] a barrier layer stacked on the substrate;

[0013] a channel layer stacked on the barrier layer, wherein a two-dimensional electron gas is generated in the channel layer above the interface between the barrier layer and the channel layer; and

[0014] A source electrode, a drain electrode and a gate electrode are arranged on the channel layer, the source electrode and the drain electrode are distributed on both sides of the gate electrode, and the source electrode and the drain electrode are electrically connected to the two-dimensional electron gas.

[0015] In one embodiment, the channel layer is an N-polarity GaN channel layer, and the barrier layer is an AlGaN barrier layer.

[0016] In one embodiment, the channel layer includes an active region and an inactive region, the inactive region is a high-resistance region, the source, drain and gate are located above the active region, and two-dimensional electron gas is formed in the active region.

[0017] In an embodiment, the source and the drain form ohmic contacts with the N-polar GaN channel layer respectively, and the gate forms a Schottky contact with the N-polar GaN channel layer.

[0018] In an embodiment, the terahertz radiation source device further comprises a source pad electrically connected with the source, a drain pad electrically connected with the drain, and a gate pad electrically connected with the gate.

[0019] In an embodiment, the terahertz radiation source device satisfies:

[0020] f=(2n-1)s / (4L g ),

[0021] wherein s is the speed of the plasma wave, f is the frequency of the radiation field, n is a natural number, L g is the length of the gate.

[0022] In an embodiment, the speed s of the plasma wave is:

[0023] s=(eU0 / m) 0.5 ,

[0024] wherein e is the electronic charge, U0 is the gate voltage, and m is the effective mass of the electron.

[0025] In an embodiment, the substrate is any one of a high-resistance silicon substrate, a sapphire substrate, or a silicon carbide substrate; and / or,

[0026] a GaN buffer layer is stacked between the substrate and the barrier layer; and / or,

[0027] a passivation layer is stacked between the channel layer and the gate.

[0028] The technical scheme provided by an embodiment of the present application is as follows:

[0029] A terahertz radiation source system comprises a plurality of array-distributed terahertz radiation source devices, and the terahertz radiation source device is the terahertz radiation source device according to any one of claims 1-8.

[0030] In an embodiment, the terahertz radiation source devices in the terahertz radiation source system are spaced apart from each other along a first direction by a distance of

[0031] The terahertz radiation source devices in the terahertz radiation source system are spaced apart from each other along a second direction by a distance of

[0032] wherein λ is the wavelength of the terahertz wave, z is a natural number, z≥2, and k is a natural number, k≥2.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] The present invention electrically connects the two-dimensional electron gas generated in the channel layer above the interface between the barrier layer and the channel layer to the source and the drain through the channel layer, thereby reducing the ohmic contact resistance, increasing the saturation current, improving the energy conversion efficiency, and increasing the output power. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 Schematic diagram of the cross-sectional structure of the terahertz radiation source device in Comparative Example 1 of the present invention;

[0037] Figure 2 Schematic diagram of the planar structure of the terahertz radiation source device in Comparative Example 2 of the present invention;

[0038] Figure 3 Schematic diagram of the planar structure of the terahertz radiation source device in Example 1 of the present invention;

[0039] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at II in the middle;

[0040] Figure 5 Schematic diagram of the planar structure of the terahertz radiation source system in Example 2 of the present invention.

[0041] Description of reference numerals:

[0042] 11-channel layer, 12-barrier layer, 131-source, 132-drain, 133-gate, 14-two-dimensional electron gas, 211-source, 212-drain, 213-gate, 221-source pad, 222-drain pad, 223-gate pad, 23-channel layer, 30-terahertz radiation source device, 301-terahertz radiation source device, 302-terahertz radiation source device, 303-terahertz radiation source device, 304-terahertz radiation source device, 31-substrate, 32-buffer layer, 33-barrier layer, 34-channel layer, 351-source, 352-drain, 353-gate, 361-source pad, 362-drain pad, 363-gate pad, 37-two-dimensional electron gas. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0044] The present invention discloses a terahertz radiation source device, comprising:

[0045] substrate;

[0046] a barrier layer stacked on the substrate;

[0047] a channel layer stacked on the barrier layer, wherein a two-dimensional electron gas is generated in the channel layer above the interface between the barrier layer and the channel layer; and

[0048] The source, drain and gate are arranged on the channel layer, the source and drain are distributed on both sides of the gate, and the source and drain are electrically connected to the two-dimensional electron gas.

[0049] The present invention also discloses a terahertz radiation source system, comprising a plurality of terahertz radiation source devices distributed in an array.

[0050] Preferably, the channel layer in the present invention is an N-polarity GaN channel layer. The two-dimensional electron gas in the N-polarity GaN channel layer can be electrically connected to the source and drain through the channel layer, which can reduce the ohmic contact resistance, increase the saturation current, improve the energy conversion efficiency, and increase the output power.

[0051] The present invention is further described below with reference to specific examples.

[0052] Comparative Example 1:

[0053] Ginseng Figure 1 The figure shows a schematic diagram of the cross-sectional structure of the terahertz radiation source device in this comparative example. The terahertz radiation source device is composed of a substrate (not shown), a channel layer 11, a barrier layer 12, a source 131, a drain 132 and a gate 133, wherein the channel layer 11 is a Ga-polar surface GaN channel layer, the barrier layer 12 is an AlGaN barrier layer, and the two-dimensional electron gas 14 is generated in the channel layer below the interface between the AlGaN barrier layer and the Ga-polar surface GaN channel layer.

[0054] Comparative Example 2:

[0055] Ginseng Figure 2 The figure shows a schematic diagram of the planar structure of the terahertz radiation source device in this comparative example. The terahertz radiation source device in this comparative example is substantially the same as that in comparative example 1, except that the settings of the source, drain and gate are different.

[0056] Specifically, the source electrode 211, drain electrode 212, and gate electrode 213 are stacked on the channel layer 23. The channel layer 23 includes an active region and an inactive region, with the inactive region forming a high-resistance region through ion implantation. The gate electrode 213 is an arrayed electrode located between the source electrode 211 and the drain electrode 212, and above the active region. The two-dimensional electron gas is formed in the channel layer below the interface between the channel layer and the barrier layer, and is located within the active region. The terahertz radiation source device in this comparative example also includes a source pad 221, a drain pad 222, and a gate pad 223.

[0057] Example 1:

[0058] Ginseng Figure 3 、 Figure 4 As shown, the terahertz radiation source device 30 in this embodiment includes:

[0059] substrate 31;

[0060] a barrier layer 33 stacked on the substrate 31;

[0061] A channel layer 34 is stacked on the barrier layer 33, and a two-dimensional electron gas 37 is generated in the channel layer above the interface between the barrier layer and the channel layer; and

[0062] A source 351 , a drain 352 and a gate 353 are disposed on the channel layer. The source 351 and the drain 352 are distributed on both sides of the gate 353 . The source 351 and the drain 352 are electrically connected to the two-dimensional electron gas 37 .

[0063] For example, the substrate 31 in this embodiment is any one of a high-resistance silicon substrate, a sapphire substrate, or a silicon carbide substrate. Meanwhile, the substrate 31 can be thinned to reduce the absorption of the terahertz wave by the substrate 31 .

[0064] Furthermore, in this embodiment, a buffer layer 32 is stacked on the substrate 31 , wherein the buffer layer 32 is a GaN buffer layer.

[0065] Furthermore, in this embodiment, the barrier layer 33 is an AlGaN barrier layer, and the channel layer 34 is an N-polarity GaN channel layer. The two-dimensional electron gas 37 is generated in the N-polarity GaN channel layer above the interface between the AlGaN barrier layer and the N-polarity GaN channel layer.

[0066] Furthermore, the channel layer 34 includes an active region and an inactive region. The inactive region is made highly resistive by methods such as ion implantation. The source 351 , the drain 352 and the gate 353 are located above the active region, and the two-dimensional electron gas 37 is located in the active region.

[0067] Furthermore, in this embodiment, the source 351 and the drain 352 are made of Ti-Au metal, forming an ohmic contact with the N-polarity GaN channel layer, and the gate 353 is made of Ni-Au metal, forming a Schottky contact with the N-polarity GaN channel layer.

[0068] Specifically, the source 351 and drain 352 are periodically arranged, with a single gate 353 interposed between them, and are formed in an opposing manner. Comparative Example 2 employs a gate array scheme, resulting in a large distance between the source 221 and drain 222. This results in very low current flow in the terahertz radiation source device of Comparative Example 2 at room temperature, often requiring operation at low temperatures. Furthermore, its energy conversion efficiency is low, making it difficult to increase output power. In contrast, the periodically arranged source 351 and drain 352 in this embodiment enable the terahertz radiation source device 30 of this embodiment to withstand higher currents and increase output power. Furthermore, the periodically arranged source 351 and drain 352 prevent significant attenuation of terahertz waves in the channel layer. Plasma waves are coupled through the periodically arranged source 351 and drain 352, radiating them to the outside world.

[0069] Preferably, the gate length in this embodiment ( Figure 3 and Figure 4 The lateral distance) is 200nm, the gate width ( Figure 3 The distance between the gate and the source and the distance between the gate and the drain are both 600 μm. The distance between two adjacent source or drain metals constituting the source or drain ( Figure 3 and Figure 4 The width of the multiple source or drain metals constituting the source or drain ( Figure 3 The longitudinal distance) is 600 μm.

[0070] For example, in this embodiment, a passivation layer may be stacked between the channel layer 34 and the gate 353 .

[0071] For example, the source and drain of the terahertz radiation source device 30 in this embodiment may be short-circuited to enable the terahertz radiation source device 30 in this embodiment to work efficiently.

[0072] Furthermore, this embodiment further includes a source pad 361 electrically connected to the source 351 , a drain pad 362 electrically connected to the drain 352 , and a gate pad 363 electrically connected to the gate 353 .

[0073] Preferably, the source pad 361 , the drain pad 362 and the gate pad 363 are prepared together when the source electrode 351 , the drain electrode 352 and the gate electrode 353 are deposited, which can simplify the preparation process.

[0074] Exemplarily, the source pad 361 , the drain pad 362 and the gate pad 363 are packaged and connected to the device by methods such as Au Wire Bonding.

[0075] The terahertz radiation source device 30 of the present invention satisfies f=(2n-1)s / (4L g ), where s is the velocity of the plasma wave, f is the frequency of the radiation field, n is a natural number, and L g is the gate length. Preferably, in this embodiment, the gate length L g is 200 nm, and the speed of the plasma wave s is about 1×10 6 m / s, when the natural number n=1, the frequency f of the radiation field in this embodiment is 1.25 THz.

[0076] Furthermore, the velocity s of the plasma wave satisfies s = (eU0 / m) 0.5 , where e is the electron charge, U0 is the gate voltage, and m is the effective mass of the electron. Since the electron charge e and the effective mass m of the electron are fixed at room temperature, the frequency of the radiation field can be adjusted by changing the gate voltage U0.

[0077] Example 2:

[0078] Ginseng Figure 5 As shown, the terahertz radiation source system in this embodiment includes multiple terahertz radiation source devices, such as four terahertz radiation source devices 301, 302, 303, and 304 arranged in parallel in this embodiment.

[0079] Specifically, the drain of the terahertz radiation source device 301 is electrically connected to the drain of the terahertz radiation source device 302; the source of the terahertz radiation source device 302 is electrically connected to the source of the terahertz radiation source device 304, the drain of the terahertz radiation source device 302 is electrically connected to the drain of the terahertz radiation source device 304, and the gate of the terahertz radiation source device 302 is electrically connected to the gate of the terahertz radiation source device 304; the source of the terahertz radiation source device 303 is electrically connected to the source of the terahertz radiation source device 304; the source of the terahertz radiation source device 301 is electrically connected to the source of the terahertz radiation source device 303, the drain of the terahertz radiation source device 301 is electrically connected to the drain of the terahertz radiation source device 303, and the gate of the terahertz radiation source device 301 is electrically connected to the gate of the terahertz radiation source device 303.

[0080] In this way, by connecting multiple terahertz radiation source devices in parallel, the driving current can be increased, the current can be uniformly distributed to each terahertz radiation source device, the radiation of multiple terahertz radiation source devices can be coupled in space, the oscillation of the plasma wave can be improved, and the output power can be improved.

[0081] Further, in the present embodiment, the spacing between two adjacent terahertz radiation source devices in the first direction (lateral direction) is The spacing between two adjacent terahertz radiation source devices in the second direction (longitudinal direction) is Wherein, λ is the wavelength of the terahertz wave, z is a natural number, z≥2, and k is a natural number, k≥2.

[0082] Exemplarily, when the frequency f of the target radiation field is 1THz, the wavelength λ of the corresponding terahertz wave is 300μm, z=k=2, and the spacing d in the two directions is x = d y = 75μm.

[0083] As can be seen from the above technical solutions, the present application has the following beneficial effects:

[0084] In the present application, the N-polarity channel layer is stacked on the barrier layer, the two-dimensional electron gas is generated in the channel layer above the interface between the barrier layer and the channel layer, the two-dimensional electron gas can be electrically connected to the source and the drain through the channel layer without passing through the barrier layer, the ohmic contact resistance can be reduced, the saturation current can be increased, the energy conversion efficiency can be improved, and the output power can be increased.

[0085] It will be apparent to those skilled in the art that the application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered as exemplary and non-limiting, and the scope of the application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the application. Any reference signs in the claims should not be considered as limiting the claims involved.

[0086] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A terahertz radiation source device, characterized in that: include: substrate; a barrier layer stacked on the substrate; A channel layer is stacked on the barrier layer, wherein a two-dimensional electron gas is generated in the channel layer above the interface between the barrier layer and the channel layer; and, A source electrode, a drain electrode and a gate electrode are arranged on the channel layer, the source electrode and the drain electrode are distributed on both sides of the gate electrode, and the source electrode and the drain electrode are electrically connected to the two-dimensional electron gas.

2. The terahertz radiation source device according to claim 1, characterized in that: The channel layer is an N-polarity GaN channel layer, and the barrier layer is an AlGaN barrier layer.

3. The terahertz radiation source device according to claim 1, characterized in that: The channel layer includes an active area and an inactive area, the inactive area is a high resistance area, the source, drain and gate are located above the active area, and two-dimensional electron gas is formed in the active area.

4. The terahertz radiation source device according to claim 2, characterized in that: The source and drain respectively form ohmic contacts with the N-polarity GaN channel layer, and the gate forms a Schottky contact with the N-polarity GaN channel layer.

5. The terahertz radiation source device according to claim 4, characterized in that: The terahertz radiation source device further includes a source pad electrically connected to the source, a drain pad electrically connected to the drain, and a gate pad electrically connected to the gate.

6. The terahertz radiation source device according to claim 1, characterized in that: The terahertz radiation source device satisfies: f=(2n-1)s / (4L g ), Where s is the speed of the plasma wave, f is the frequency of the radiation field, n is a natural number, L g is the gate length.

7. The terahertz radiation source device according to claim 6, characterized in that: The velocity s of the plasma wave is: s=(eU0 / m) 0.5 , Where e is the electron charge, U0 is the gate voltage, and m is the effective mass of the electron.

8. The terahertz radiation source device according to claim 1, characterized in that: The substrate is any one of a high-resistance silicon substrate, a sapphire substrate or a silicon carbide substrate; and / or, A GaN buffer layer is stacked between the substrate and the barrier layer; and / or, A passivation layer is stacked between the channel layer and the gate.

9. A terahertz radiation source system, comprising a plurality of terahertz radiation source devices distributed in an array, wherein the terahertz radiation source device is the terahertz radiation source device according to any one of claims 1 to 8.

10. The terahertz radiation source system according to claim 9, characterized in that: The spacing between the terahertz radiation source devices in the terahertz radiation source system along the first direction is The spacing between the terahertz radiation source devices in the terahertz radiation source system along the second direction is Wherein, λ is the wavelength of the terahertz wave, z is a natural number, z ≥ 2, and k is a natural number, k ≥ 2.

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