Disclosure of Invention
The technical problem to be solved by the invention is as follows: the terahertz oscillation source of the resonant tunneling diode is provided, and the output power of the oscillator is greatly improved by increasing the area of a device of the resonant tunneling diode.
In order to solve the above technical problem, the present invention provides a resonant tunneling diode terahertz oscillation source, including: the resonant tunneling diode, the resonant cavity, the MIM capacitor and the butterfly antenna;
the MIM capacitor comprises a dielectric layer, an upper metal layer and a lower metal layer, wherein the upper metal layer comprises a left supporting column, a middle supporting column, a right supporting column and an upper metal plane layer, the middle supporting column is positioned in the middle of the upper metal plane layer, and the dielectric layer is used for separating the left supporting column and the right supporting column from the lower metal layer;
the resonant cavity is divided into a first resonant cavity and a second resonant cavity, the first resonant cavity is formed by the upper metal plane layer, the left side supporting column, the middle supporting column and the lower metal layer, the second resonant cavity is formed by the upper metal plane layer, the right side supporting column, the middle supporting column and the lower metal layer, and the first resonant cavity and the second resonant cavity are symmetrical to each other;
the resonant tunneling diode is arranged at the symmetrical position of the first resonant cavity and the second resonant cavity, the first end of the resonant tunneling diode is connected with the middle support column, and the second end of the resonant tunneling diode is connected with the lower metal layer;
the left supporting column is connected with a first pole of the butterfly antenna, and the right supporting column is connected with a second pole of the butterfly antenna;
the first pole of the butterfly antenna and the second pole of the butterfly antenna are coupled through a MIM capacitor.
Further, the device also comprises a stable resistor;
the first end of the stabilizing resistor is connected with the upper metal layer of the resonant cavity, and the second end of the stabilizing resistor is connected with the lower metal layer of the resonant cavity.
Further, the bowtie antenna is used for guiding and radiating the terahertz waves in the resonant cavity.
Further, the size of the bowtie antenna is determined by its radiation wavelength.
Further, the first pole of the butterfly antenna and the second pole of the butterfly antenna are coupled through a MIM capacitor.
Furthermore, the resonant cavity has three variables of length, width and height;
the length of the resonant cavity is determined by calculating a resonant frequency calculation formula of a main mode of the resonant cavity and corresponding design frequency, the width of the resonant cavity is determined by the area of the selected resonant tunneling diode, and the height of the resonant cavity is determined by the thickness of photoresist.
Further, the area of the resonant tunneling diode is determined by the oscillator output power and the output power of the resonant tunneling diode per unit area.
Further, the resonant tunneling diode is fed through an upper metal layer of the MIM capacitor and a lower metal layer of the MIM capacitor.
Further, the MIM capacitor is configured to dc isolate the upper metal layer from the lower metal layer.
Compared with the prior art, the terahertz oscillation source of the resonant tunneling diode provided by the embodiment of the invention has the following beneficial effects:
the invention provides a resonance tunneling diode terahertz oscillation source, which comprises: the resonant tunneling diode, the resonant cavity and the MIM capacitor;
the MIM capacitor comprises an upper metal layer and a lower metal layer, wherein the upper metal layer comprises a left side supporting column, a middle supporting column, a right side supporting column and an upper metal plane layer, and the middle supporting column is positioned in the middle of the upper metal plane layer; the resonant cavity is divided into a first resonant cavity and a second resonant cavity, the first resonant cavity is formed by the upper metal plane layer, the left side supporting column, the middle supporting column and the lower metal layer, the second resonant cavity is formed by the upper metal plane layer, the right side supporting column, the middle supporting column and the lower metal layer, and the first resonant cavity and the second resonant cavity are symmetrical to each other; the resonant tunneling diode is arranged at the symmetrical position of the first resonant cavity and the second resonant cavity, the first end of the resonant tunneling diode is connected with the middle support column, the second end of the resonant tunneling diode is connected with the lower metal layer, and the area of the resonant tunneling diode is increased by arranging the resonant tunneling diode device in the resonant cavity, so that the output power of the oscillator is improved.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Referring to fig. 1a and 1b, fig. 1a and 1b are schematic structural diagrams of an embodiment of a resonant tunneling diode terahertz oscillation source provided by the present invention, as shown in fig. 1a and 1b, the structure includes a resonant tunneling diode 1, a resonant cavity, and an MIM capacitor 3, specifically as follows:
the MIM capacitor 3 comprises an upper metal layer 31 and a lower metal layer 32, the upper metal layer comprising a left side support pillar 33, a middle support pillar 34, a right side support pillar 35 and an upper metal plane layer 37, the middle support pillar 34 being located in the middle of the upper metal plane layer 37.
In this embodiment, the MIM capacitor 3 further includes a dielectric layer 36, the MIM capacitor 3 has a structure including an upper metal layer 31, a dielectric layer 36, and a lower metal layer 32 from top to bottom, the dielectric layer 36 is used to separate the left support pillar 33 and the right support pillar 35 from the lower metal layer 32, the dielectric layer 36 is made of silicon dioxide, and the MIM capacitor 3 is mainly used for dc isolation to separate dc from radio frequency.
The resonant cavity is divided into a first resonant cavity 21 and a second resonant cavity 22, the first resonant cavity 21 is formed by an upper metal plane layer 37, a left side supporting column 33, a middle supporting column 34 and a lower metal layer 32, the second resonant cavity 22 is formed by an upper metal plane layer 37, a right side supporting column 35, a middle supporting column 34 and a lower metal layer 32, and the first resonant cavity 21 and the second resonant cavity 22 are symmetrical to each other.
In the embodiment, the resonant cavity is used for generating high-frequency resonant waves and has three variables of length, width and height; the length a of the resonant cavity is determined by calculating a resonant frequency calculation formula of a main mode of the resonant cavity and corresponding design frequency;
the resonant frequency calculation formula of the resonant cavity main mode is as follows:
wherein f is frequency, v is voltage, a is resonant cavity length, b is resonant cavity width, and c is resonant cavity height;
the length a of the resonant cavity is the sum of the length of the first resonant cavity, the length of the second resonant cavity and the length of the middle supporting column, wherein the length of the middle supporting column is set to be 2um;
the width b of the resonant cavity is determined by the area of the selected resonant tunneling diode, and after the area s of the resonant tunneling diode is obtained, the width b is determined by the formula: b = s/2, calculating the width b of the resonant cavity;
the height c of the cavity is designed according to the process level used and is limited by the photoresist thickness of the MIM capacitor support posts.
The resonant tunneling diode 1 is disposed at a symmetrical position of the first resonant cavity 21 and the second resonant cavity 22, a first end of the resonant tunneling diode 1 is connected to the middle support pillar 34, and a second end of the resonant tunneling diode 1 is connected to the lower metal layer 32.
In this embodiment, the resonant tunneling diode 1 is embedded in the symmetric center of the resonant cavity, and is fed through the upper metal layer 31 and the lower metal layer 32 of the MIM capacitor 3, and based on the existing resonant tunneling diode device, the negative resistance I-V curve thereof can be obtained by a semiconductor parameter analyzer, as shown in fig. 2, where the peak current density is 4.8mA/um 2 The peak-to-valley current value difference delta I is 3.6mA, the negative resistance voltage interval delta V is 0.2V, and the junction capacitance C of the obtained diode is 5fF/um 2 The resistance R of the junction is 5 omega um 2 ;
The area of the resonant tunneling diode 1 is determined according to the required obtained oscillator output power and the output power of the resonant tunneling diode 1 per unit area, wherein the output power of the resonant tunneling diode 1 per unit area is Δ V × Δ I.
Referring to fig. 1a and fig. 1b, a schematic structural diagram of an embodiment of a resonant tunneling diode terahertz oscillation source provided by the present invention is shown in fig. 1a and fig. 1b, and the structure further includes a stabilizing resistor 4 and a butterfly antenna 5;
a first end of the stabilizing resistor 4 is connected with the upper metal layer 31 of the MIM capacitor 3, and a second end of the stabilizing resistor 4 is connected with the lower metal layer 32 of the MIM capacitor 3; the left support post 33 is connected to a first pole of the dish antenna 5 and the right support post 35 is connected to a second pole of the dish antenna 5.
In this embodiment, since the resonant cavity does not have a radiation characteristic, the high-frequency resonant wave generated in the resonant cavity cannot be radiated, so that a corresponding butterfly antenna needs to be designed on the periphery of the cavity according to a required frequency band to guide and radiate the terahertz wave in the resonant cavity, and the resonant cavity is coupled with the butterfly antenna 5 through the lower metal layer 32 of the MIM capacitor 3; the size of the dish-shaped antenna 5 is determined by the wavelength of the high-frequency resonant wave generated by the resonant cavity, the specific size is one quarter of the wavelength, and the opening angle degree of the dish-shaped antenna 5 can be set according to requirements, can be set to 45 degrees, and can also be set to 60 degrees. Meanwhile, the resonant tunneling diode 1 has a strong negative resistance characteristic, and a resonant circuit is formed by utilizing the capacitance effect of the resonant tunneling diode 1 and the inductance provided by the external matching circuit, but the butterfly antenna is designed to be an ultra-wideband antenna with real impedance, so that the butterfly antenna does not need to participate in the matching of the oscillator.
In this embodiment, the impedance is designed by optimizing the design mainly through full-wave electromagnetic simulation software HFSS, and in the optimization design process, through electromagnetic coupling analysis, the coupling parasitic effect generated by coupling between the resonant cavity and the butterfly antenna 5 through the lower metal layer 32 of the MIM capacitor 3 is considered at the same time, so that the performance is further optimized.
As another example of this embodiment, according to different device models and frequency band requirements of different users, the full-wave electromagnetic simulation software HFSS can be used to perform optimization and design a suitable antenna structure.
Referring to fig. 3, fig. 3 is a simulation result diagram of an embodiment of the resonant tunneling diode terahertz oscillation source provided by the invention, the simulation result diagram is based on the terahertz oscillation source with a design target of 800GHz-1THz, and the used area is 5-10 um 2 The peak current density of the resonant tunneling diode 1 is 4mA/um 2 The peak-to-valley current ratio is 4, the negative resistance voltage interval is 0.4V, the resonant cavity length a is 32um, the resonant cavity width b is 14um, the resonant cavity height c is 3um, the support pillar thickness is 2um, the stable resistance value is 4 ohms, the butterfly antenna 5 is 1000um wide and 272um long, and the opening angle is 60 degrees, an effect diagram obtained by simulation through full-wave electromagnetic simulation software HFSS is obtained, it can be seen from the simulation result diagram that the junction area of the resonant tunneling diode device is related to the output power and the frequency, in the terahertz frequency band, the power output can be effectively improved by improving the junction area of the resonant tunneling diode device, and the high-power output of 0.1mW can be obtained under the frequency of 1 THz.
In summary, the present embodiment provides a resonant tunneling diode terahertz oscillation source, including: the resonant tunneling diode, the resonant cavity and the MIM capacitor; the MIM capacitor comprises an upper metal layer and a lower metal layer, wherein the upper metal layer comprises a left side supporting column, a middle supporting column, a right side supporting column and an upper metal plane layer, and the middle supporting column is positioned in the middle of the upper metal plane layer; the resonant cavity is divided into a first resonant cavity and a second resonant cavity, the first resonant cavity is formed by the upper metal plane layer, the left side supporting column, the middle supporting column and the lower metal layer, the second resonant cavity is formed by the upper metal plane layer, the right side supporting column, the middle supporting column and the lower metal layer, and the first resonant cavity and the second resonant cavity are symmetrical to each other; compared with the prior art, the area of the resonant tunneling diode device is increased by arranging the resonant tunneling diode device in the resonant cavity, so that the output power of the oscillator is increased.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.