CN113410110A

CN113410110A - Semiconductor vacuum diode

Info

Publication number: CN113410110A
Application number: CN202110513830.4A
Authority: CN
Inventors: 沈志华; 李巧宁; 葛滨; 董新奕; 姜林林
Original assignee: Nantong Vocational College
Current assignee: Nantong Vocational College
Priority date: 2021-05-07
Filing date: 2021-05-07
Publication date: 2021-09-17
Anticipated expiration: 2041-05-07
Also published as: CN113410110B

Abstract

The invention discloses a semiconductor vacuum diode, which is formed by sequentially overlapping an electrode A, a dielectric body and a semiconductor electrode B, wherein the electrode A is made of metal with lower work function, a through vacuum channel is arranged in the middle of the dielectric body, and the electrode B is made of heavily doped semiconductor; when the electrode is used, the electrode A and the electrode B are respectively connected with one electrode of a direct current power supply. The diode has the advantages of stable working performance in a high-temperature and high-radiation environment, more excited electrons and larger current, high tolerance on the process deviation of the dielectric layer film thickness in the preparation process and the like.

Description

Semiconductor vacuum diode

Technical Field

The invention relates to a vacuum diode used in the electronic industry.

Background

The structure of a common vacuum diode is that two electrodes which are separated by a certain distance are arranged in a vacuum glass tube, and an electric heating element is arranged near one electrode (negative electrode) to excite electrons.

With the development of semiconductor technology, solid-state electronic devices, such as MOSFETs, have gradually replaced vacuum electronic devices such as vacuum diodes and triodes in many fields, and compared to vacuum electronic devices, solid-state electronic devices have many advantages such as simple manufacturing process, low cost, small volume, and easy integration on integrated circuits. However, the vacuum electronic device has the advantages of large working current, stability in high-radiation and high-temperature environments and the like, so that the vacuum electronic device can not be replaced in some special fields.

Metal work function is the minimum energy (usually in electron volts) that must be provided to allow a particle of electrons to escape from the solid surface immediately. Work function is an important attribute of metal, the size of which is usually about half of the ionization energy of free atoms of metal, and by utilizing the work functions of different metals, a new technical product can be constructed.

Application No.: 2014106918549 discloses a method for processing a vacuum diode, which comprises the following steps: a. welding one ends of the two first nickel sheets to the anode and bending the first nickel sheets to form an anode support assembly; b. welding one end of a second nickel sheet with a metal lead of the first core column with the lamp filament, and welding the other end of the second nickel sheet with a metal lead at the top of the second core column to form an insulating support; c. welding two first tantalum sheets at the bottom of the cathode in a staggered manner, and respectively welding the first tantalum sheets and the third nickel sheet to form a cathode support assembly; d. welding a third nickel sheet on the metal lead wire at the top of the first core column and welding a cathode with the metal lead wire of the first core column through the bottom of the second tantalum sheet; e. mounting the diode base structure in a glass tube to form a vacuum diode; the upper surface of the cathode is parallel to the lower surface of the anode. The vacuum diode glass tube is easy to break, and additional energy is consumed by electric auxiliary heating.

Disclosure of Invention

The purpose of the invention is as follows:

the invention provides a novel semiconductor vacuum diode, which realizes the preparation of a vacuum electronic device by adopting a special structural shape through a traditional processing technology, combines the advantages of the traditional solid electronic device and the vacuum electronic device, and has more advantages of stable and high working performance under a high-temperature and high-radiation environment, high tolerance to the thickness deviation of a dielectric layer and the like.

The technical scheme is as follows:

the semiconductor vacuum diode is formed by sequentially overlapping three material layers of an electrode A, a dielectric body and an electrode B (a three-layer film structure or a three-layer plate structure which is tightly connected is manufactured by adopting magnetron sputtering, chemical vapor deposition, electron beam evaporation or gluing process), wherein the electrode A is made of metal, and a vacuum channel which penetrates through the upper material layer and the lower material layer is arranged in the middle of the dielectric body (a connecting channel which can be locally sunken is arranged in the electrode A or the motor B, and the diameter of the connecting channel of the electrode A and the electrode B is smaller than that of the vacuum channel of the dielectric body, so that electrons can be emitted or collected in a. The electrode B is made of a heavily doped semiconductor material (an N-type or P-type silicon wafer can respectively provide more free electrons or holes); in use, the electrode a and the electrode B are each connected to one electrode of a dc power supply.

Preferably, the electrode A is made of a metal material with a lower work function, and the electrode B is made of a heavily doped P-type semiconductor material; when the electrode is used, the electrode A is connected with the negative electrode of a direct current power supply, and the electrode B is connected with the positive electrode of the direct current power supply. It is further preferable that the electrode a is a material (e.g., metallic lithium, metallic magnesium, etc.) which has a relatively low work function, is relatively inexpensive, is easily etched, and has relatively stable properties.

Or the electrode A is made of a metal material with a lower work function, and the electrode B is made of a heavily doped N-type semiconductor material; when the electrode is used, the electrode A is connected with the positive pole of a direct current power supply, and the electrode B is connected with the negative pole of the direct current power supply.

The dielectric is an organic film or an inorganic film, and preferably a high dielectric ceramic film or a ceramic sheet, which has good insulation properties and a high dielectric constant. The structure of the invention is similar to a capacitor, the dielectric constant is high, the capacitance value is large, the electric charge which is enriched between two polar plates of the capacitor or in a vacuum channel (preferably, a narrow channel with the width smaller than the height and the capacitance reduction is less) is large, and the current in the circuit is large.

The vacuum channels may be obtained by dry etching or wet etching or by machining processes. The dielectric layer thickness is typically controlled below 100nm to approximate the vacuum channel length to the mean free path of electrons in atmospheric conditions, in which case such devices can operate in atmospheric conditions with effects similar to those of vacuum.

The electrode A is provided with holes communicated with the holes of the dielectric body, and a metal cover plate layer is arranged above the electrode A and is made of a metal material with a higher function; when the electrode is used, the electrode A or the metal cover plate is connected with one pole of a power supply, and the electrode B is connected with the other pole of a direct current power supply.

The metal cover plate is made of a metal material with stable chemical properties, such as gold (or gold-plated), silver (or silver-plated), nickel or carbon (preferably graphene with high mechanical strength and good conductivity), and is used as an electron collecting and protecting layer.

When bias voltage is applied to the diode, charge aggregation is formed on one side of the interface of the electrode A and the dielectric layer, which is close to the electrode A, so that quasi-two-dimensional electron gas is formed, electrons close to the vacuum channel are subjected to the action of coulomb repulsion force of other electrons in the vacuum channel, and surface potential barriers are easily overcome, so that electron emission is formed. Depending on the magnitude of the applied bias, the electron emission follows different emission laws. In this patent, the diode is biased at 5V or less, and the electron emission law follows the space charge current limiting law in thermionic emission. Under the working state, the current in the diode is independent of the temperature, and the diode can stably work in a larger temperature range, and the maximum working temperature can reach 650 ℃ (the melting point temperature) by taking the electrode A (cathode) as metal magnesium as an example.

This patent focuses on space charge confinement in thermionic emission. The prior art does not aim at the characteristic research of devices under a space charge limiting region, the patent emphatically explains the temperature stability characteristic and the process stability of the devices under the space charge limiting region, and the devices can be used as diode devices which can stably work in a larger temperature range and are suitable for large-scale production of devices with uniform performance based on the working mechanism.

Has the advantages that:

compared with solid-state electronic devices such as PN junction diodes, the vacuum diode provided by the invention can stably work at higher temperature. In the traditional semiconductor diode, charge transport is carried out in a semiconductor material, and the semiconductor material has obvious intrinsic excitation at high temperature (generally not higher than 200 ℃), large leakage current and failure of the diode. The conducting channel of the vacuum diode provided by the patent is vacuum and is not influenced by temperature. Meanwhile, the current does not change obviously with the temperature rise under the influence of space charge limiting current.

Compared with a vacuum electronic device, such as a field emission vacuum diode, a field emission cathode is usually in a tip structure, the preparation is complex, the tip structure can be degraded due to factors such as arc discharge and the like in the using process, and the reliability is poor. The working voltage of the vacuum diode provided by the patent is lower. In order to ensure a significant field emission current, the operating voltage of the field emission vacuum diode is usually above 10V, while the operating voltage of the vacuum diode proposed in this patent is usually below 5V to achieve electron excitation.

Under the diode structure and the electron emission rule, the relation between the current of the diode and the thickness of the dielectric layer is small, and the tolerance on the process deviation of the thickness of the dielectric layer is high.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention;

FIG. 2 is a schematic view of a connection configuration of the present invention in use;

fig. 3 is a schematic view of another connection configuration of the present invention in use.

FIG. 4 is a graph of data showing the variation of current at different temperatures in the diode of FIG. 2;

fig. 5 is a data plot of current as a function of dielectric layer thickness in the diode of fig. 2.

In the figure, 1-electrode B; 2-a dielectric body; 3-electrode A; 4-vacuum channel; 5-metal cover plate.

Detailed Description

The first embodiment is as follows:

the semiconductor vacuum diode shown in FIG. 1 has a three-layer film structure or a three-layer plate structure formed by sequentially stacking three materials, namely, an electrode A, a dielectric body and an electrode B; the electrode A is made of metal with lower work function, a vacuum channel penetrating the upper material layer and the lower material layer is arranged in the middle of the dielectric body, and the electrode B is made of heavily doped semiconductor material; in use, as shown in fig. 2 or fig. 3, the electrode a and the electrode B are used to connect to one electrode of a dc power supply, respectively.

For the vacuum diode device proposed in this patent, electromagnetic simulation software based on a finite integration technology is adopted to simulate the device characteristics, and the obtained results are as shown in fig. 4 and 5. In the simulation process, the structure of fig. 2 is used, and other key parameters include a dielectric layer thickness of 60nm and a vacuum channel radius of about 30 μm. As can be seen from fig. 4, at higher temperatures (the device operates in the space charge confinement region), as the temperature increases, the current in the diode remains constant, and stable operation at high temperatures can be achieved. And the lower the operating voltage, the wider the temperature range in which the diode stably operates. As can be seen from fig. 5, at a certain operating voltage, the current in the diode has little variation with the thickness of the dielectric layer, thereby achieving high tolerance to process variation of the thickness of the dielectric layer.

Example two:

in fig. 2, a diode electrode B is applied with a positive voltage (anode), an electrode a is applied with a negative voltage (cathode), a quasi-two-dimensional electron gas is formed at the electrode a side at the interface of the electrode a and the dielectric layer, and electrons are emitted from the electrode a near the interface and collected by the electrode B.

Example three:

FIG. 3 is a schematic view of the structure of FIG. 2 with a layer of electrode material added, covering the vacuum channel, the diode electrode A applying a positive voltage, the electrode B applying a negative voltage, the vacuum channel collecting electrons excited by the electrode B and transporting them to the electrode A or the metal cover plate.

Claims

1. A semiconductor vacuum diode, characterized by: a three-layer film structure or a three-layer plate structure formed by sequentially overlapping three materials of an electrode A, a dielectric body and an electrode B; the electrode A is made of metal with lower work function, a vacuum channel penetrating the upper material layer and the lower material layer is arranged in the middle of the dielectric body, and the electrode B is made of heavily doped semiconductor material; in use, the electrode a and the electrode B are each connected to one electrode of a dc power supply.

2. A semiconductor vacuum diode as claimed in claim 1, characterized in that: when the electrode B is made of a heavily doped semiconductor material, the electrode A is connected with the negative electrode of the direct-current power supply, and the electrode B is connected with the positive electrode of the direct-current power supply; when the electrode B is made of heavily doped N materials, the electrode A is connected with the anode of a direct current power supply, and the electrode B is connected with the cathode of the direct current power supply.

3. A semiconductor vacuum diode as claimed in claim 1 or 2, characterized in that: the electrode A is provided with a hole which is communicated with the hole of the dielectric body, a metal cover plate layer is arranged above the electrode A, and the metal cover plate is made of metal material with higher work function; when the electrode is used, the electrode A or the metal cover plate is connected with one pole of a power supply, and the electrode B is connected with the other pole of a direct current power supply.

4. A semiconductor vacuum diode as claimed in claim 1, characterized in that: the diameter of the connecting passage of the electrode A is smaller than that of the dielectric vacuum passage.

5. A semiconductor vacuum diode as claimed in claim 3, characterized in that: the electrode A is made of metal lithium or metal magnesium; the metal cover plate is made of gold, copper-plated gold, silver, copper-plated silver, nickel or copper-plated nickel, or is made of graphene.