Bidirectional conduction longitudinal structure diode and manufacturing method thereof

Abstract

The invention belongs to the technical field of semiconductor devices, and discloses a bidirectional conduction longitudinal structure diode and a preparation method thereof. The diode provided by the invention is provided with an anode, a cathode and an organic-inorganic heterojunction; the area covered by the anode is a heterojunction P-type semiconductor layer, and the heterojunction P-type semiconductor layer is composed of a DPPT-TT film formed by coating an undoped intrinsic DPPT-TT solution; an area covered by the cathode is a heterojunction N-type semiconductor layer, and the heterojunction N-type semiconductor layer is a silicon wafer doped with 1019 (cm <-3 >) phosphorus atoms; the anode adopts copper as a contact material; and the cathode is an indium sheet. By introducing a new tunnel composite current mode, the charge transport capability is enhanced. The novel heterojunction structure effectively improves the injection and transmission process of carriers at the electrode, and the contact resistance is remarkably reduced. The electrode modification scheme not only can improve the conductivity of the device, but also can improve the overall energy transmission efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor devices and relates to a bidirectionally conductive vertical structure diode and a manufacturing method thereof. Background Art

[0002] A bidirectional diode is a diode with bidirectional conductivity, which can conduct current under forward and reverse voltage. This diode combines the unidirectional conduction characteristics of an ordinary diode and the bidirectional protection characteristics of a bidirectional constant current diode such as a Zener diode.

[0003] The structure of a bidirectional diode is similar to that of an ordinary diode, but its internal design allows it to conduct current under both forward and reverse voltage conditions. It is usually made of silicon material and uses a PN structure to achieve bidirectional conductivity. When a forward voltage is applied, the bidirectional diode behaves like a normal diode, and current can flow from the positive electrode to the negative electrode, playing a forward conduction role; in the case of a reverse voltage, the bidirectional diode behaves like a bidirectional protection diode. When the reverse voltage reaches a certain value, the device will begin to conduct, protecting the circuit from overvoltage damage.

[0004] Bidirectional diodes play an important role in electronic circuits due to their unique bidirectional conductivity, especially in situations where bidirectional conductivity and protection are required. For example, bidirectional diodes are used in power management circuits for functions such as voltage stabilization, current limiting and overvoltage protection to improve the stability and safety of the circuit; in communication equipment, bidirectional diodes are often used to protect lines, interfaces and other electronic components to prevent damage caused by voltage surges, electrostatic discharge, etc.; in automotive electronic systems, bidirectional diodes can be used to protect on-board electronic equipment to prevent equipment failures caused by electromagnetic interference, overvoltage and other factors. In industrial automation and control systems, bidirectional diodes are widely used to protect key equipment such as PLCs, sensors, actuators, etc. to ensure system stability and reliability.

[0005] In recent years, organic semiconductors have developed rapidly due to their wide range of applications, mainly due to the lightness and flexibility of organic materials, which make them show unparalleled advantages in various applications. For example, in the fields of wearable devices, flexible electronic products and large-area displays, organic semiconductor materials have broad application prospects. However, despite the outstanding performance of organic semiconductors in these aspects, their electron and hole mobility is generally lower than that of inorganic semiconductors, which limits the switching speed and response time of the device. Specifically, the low mobility leads to the limited performance of organic semiconductor devices in high-frequency applications, which cannot meet the needs of fast switching and efficient signal processing. In addition, most organic semiconductor devices lack matching ohmic contact electrodes during design, resulting in excessive contact resistance. This large contact resistance not only affects the conductive properties of the device, but also limits the effective injection of carriers between the electrode and the organic material, thereby reducing the overall efficiency of the device. The high bulk resistance of organic materials is also an important issue, which further limits the transmission efficiency of carriers, resulting in large energy losses. This energy loss not only affects the working efficiency of the device, but also may cause the performance of the device to decay after long-term use. Therefore, improving the electrical properties of organic semiconductor devices, especially reducing contact resistance and improving energy transfer efficiency, is an important direction of current organic electronics research.

[0006] In general, the low carrier density and mobility of organic materials are one of the main factors that restrict the performance of organic devices. These organic materials usually exhibit relatively low electrical conductivity, which will directly lead to a decrease in the energy transfer efficiency in the device. In traditional organic devices, the carrier concentration in the electrode area is low. This low concentration of carriers not only leads to an increase in the contact resistance between the electrode and the organic material, but also limits the overall conduction performance of the device. Summary of the invention

[0007] In response to the above technical problems, this application combines organic semiconductors and highly doped silicon to construct a new type of organic-inorganic heterojunction for making diodes, and proposes a bidirectionally conductive longitudinal structure diode based on an organic-inorganic heterojunction composed of silicon and DPPT-TT. By introducing a new tunnel recombination current mode, the charge transport capacity is enhanced. This new heterojunction structure effectively improves the injection and transport process of carriers at the electrode and significantly reduces the contact resistance. This electrode modification scheme can not only improve the conductivity of the device, but also improve the overall energy transfer efficiency.

[0008] In a first aspect, the present invention provides a bidirectionally conductive vertical structure diode, comprising:

[0009] Anodes, cathodes, and organic-inorganic heterojunctions;

[0010] The area covered by the anode is a P-type semiconductor layer of the heterojunction, which is composed of a DPPT-TT film formed by coating an undoped intrinsic DPPT-TT solution; preferably, the solute of the DPPT-TT solution is DCB and the concentration range of DPPT-TT in the DPPT-TT / DCB solution is 1 to 15 mg / ml;

[0011] The area covered by the cathode is an N-type semiconductor layer of the heterojunction, which is doped with 10 -19 (cm -3 )Silicon wafer with phosphorus atoms.

[0012] The anode uses copper as the contact material;

[0013] The cathode is an indium sheet.

[0014] In a second aspect, the present invention provides a method for manufacturing the above-mentioned bidirectionally conductive vertical structure diode, the manufacturing method comprising the steps of:

[0015] After ultrasonic cleaning of the highly doped silicon wafer, a tape for spin coating mask is pasted, and a DPPT-TT / DCB solution is spin coated on the surface to prepare an organic semiconductor layer, which is then heated at 80° C. for 5 minutes and then annealed at 150° C. for 1 hour; after tearing off the tape to remove the DPPT-TT material in the middle area, an indium sheet is adhered to the middle area, that is, the indium sheet is directly adhered to the highly doped silicon wafer in the middle area; and an anode is made on the organic semiconductor layer.

[0016] Preferably, the concentration of DPPT-TT in the DPPT-TT / DCB solution is 5 mg / ml. Accordingly, the spin coating parameters of the DPPT-TT / DCB solution are set as follows: the initial speed of spin coating is 0 rpm, and it is accelerated to 500 rpm at an acceleration of 200 rpm / s, and the acceleration and uniform speed time of this stage last for a total of 10 s; then it is accelerated to 1500 rpm at an acceleration of 500 rpm / s, and the acceleration and uniform speed time of this stage last for a total of 60 s; then it is decelerated to 0 rpm at an acceleration of 500 rpm / s, and the deceleration and stop time of this stage last for a total of 5 s.

[0017] Preferably, the anode is made by evaporation or magnetron sputtering. It should be noted that the anode is made in a corresponding shape after a metal mask is designed according to different circuit structures by layout design software. Further preferably, the anode is made by evaporation, and the manufacturing steps include: first 5nm of metal Cu was evaporated at a speed of 70nm of Cu metal was deposited at a speed of 5 nm of metal Cu was evaporated at a rate of , and finally a metal Cu anode with a thickness of 80 nm was formed by evaporation.

[0018] Technical principle: Due to lattice mismatch, there are a large number of interface states between silicon and DPPT-TT. These interface states, like surface states, may be partial acceptors and partial donors. In order to achieve equilibrium, the materials on both sides of the interface release electrons to the acceptors. If the concentration of the interface state is high enough, two positively charged depletion layers will be generated. The sum of their charges is equal to the charge of the unipolar layer of the interface state and has opposite polarity. They are spatially confined in an extremely thin layer, the "interface", and are in an extremely narrow energy range. This feature makes the Fermi levels on both sides remain unchanged under an applied voltage. In addition, their total capture cross section is so large that all electrons passing through the interface will be captured and re-emitted by these states. In the heterojunction diode prepared by the present invention, the influence of the interface state on both sides can be replaced by a metal interlayer, which forms a metal-semiconductor contact with the semiconductors on both sides. The interface can be equivalent to two reverse series Schottky diodes, and the heavy doping on the silicon side triggers tunneling in the corresponding depletion layer barrier.

[0019] For an independent ideal diode, we can easily extract the various parameters we want through the output characteristic curve. However, the actual experiment is often the result of the combined effect of various factors. For organic-inorganic heterojunction diodes based on silicon and DPPT-TT, there are not only reverse series Schottky diodes, but also variable body resistance, which adds many difficulties to the experiment. Therefore, the derivative research method is used to analyze its volt-ampere characteristics, which can provide more accurate information for complex structures such as heterojunctions. A single tube can be regarded as an ideal diode, and the shunt resistance R sh And the series resistor R. As shown in formula (1).

[0020]

[0021] Generally take R sh is positive infinity, V j =VI j R, then we can get formula (2):

[0022]

[0023] In this way, the measurement sensitivity can be increased and the The slope of the straight line gives the series resistance R, which can eliminate the influence of the change in bulk resistance.

[0024] The silicon layer region is verified to be in ohmic contact with the cathode, and there is a heterojunction interface between the silicon layer region and the DPPT-TT region. A new tunnel recombination current is introduced through the silicon layer region with a high doping concentration to achieve a larger forward conduction current under the same voltage.

[0025] Beneficial effects: The bidirectionally conductive longitudinal structure diode provided by the present invention combines the two materials of organic semiconductor DPPT-TT and highly doped silicon to form an organic-inorganic heterojunction based on silicon and DPPT-TT. The constructed diode has a lower electrode contact resistance, which enables carriers to be more efficiently injected into the organic material. Therefore, the device exhibits a higher on-current. This improvement not only improves the operating efficiency of the device, but also lays the foundation for their use in high-performance applications. For example, in photoelectric conversion and energy storage systems, improving the current carrying capacity can significantly improve the overall efficiency and make the device more competitive; in addition, another potential advantage of the organic-inorganic heterojunction diode based on silicon and DPPT-TT is its flexibility in heterogeneous material systems. By precisely controlling the ratio and interface structure of the organic and inorganic components, the device performance can be further optimized to achieve higher efficiency and stability.

[0026] Overall, the organic-inorganic heterojunction diode based on silicon and DPPT-TT improves the charge transport capability by solving the contact resistance problem existing in traditional organic devices, marking an important progress in the field of organic electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural diagram of an organic-inorganic heterojunction diode based on silicon and DPPT-TT in the present invention;

[0028] Figure 2 It is a flow chart of an organic-inorganic heterojunction diode based on silicon and DPPT-TT in the present invention;

[0029] Figure 3 It is a physical picture of the organic-inorganic heterojunction diode based on silicon and DPPT-TT in the present invention;

[0030] Figure 4 is a flow chart of the preparation of the longitudinal SBD based on DPPT-TT in Comparative Example 1 of the present invention;

[0031] Figure 5 is an output characteristic curve diagram of an organic-inorganic heterojunction diode based on silicon and DPPT-TT at different temperatures in the present invention;

[0032] Figure 6 It is a curve showing the change of reverse saturation current of the organic-inorganic heterojunction diode based on silicon and DPPT-TT with temperature in the present invention.

[0033] Figure 7 This is the output characteristic curve of the longitudinal SBD based on DPPT-TT in Comparative Example 1 at room temperature. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments, but the present invention is not limited to these embodiments. The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following embodiments of the present invention, and those skilled in the art can fully understand the present invention without the description of these details.

[0035] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "middle", "upper", "lower", "left", "right", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The sources of the reagent kit materials and equipment used in the following embodiments and test examples are as follows:

[0037] DPPT-TT: Nanjing Zhiyan Technology Co., Ltd.; dichlorobenzene (DCB) solution: Sigma-Aldrich; doped with phosphorus, concentration of 10 19 (cm -3 ) was purchased from Guangzhou Fangdao Semiconductor Co., Ltd.

[0038] Example 1

[0039] Example 1 takes the preparation of an organic-inorganic heterojunction diode based on silicon and DPPT-TT as an example to illustrate the preparation process of the present invention; Figure 1 As shown, the heterojunction diode involved in the following embodiments includes a substrate 1, a cathode 2, an anode 3, and an organic semiconductor layer 4. The substrate 1 is a doping concentration of 10 19 (cm -3 ) of an N-type silicon substrate; the anode 2 is a metal copper electrode, and the cathode uses indium; the organic semiconductor layer 4 is an intrinsic organic material DPPT-TT film.

[0040] Example 1 provides a process for manufacturing an organic-inorganic heterojunction diode based on silicon and DPPT-TT as follows:

[0041] Step S1, a 0.5 mm thick highly doped silicon substrate is ultrasonically treated in alcohol and deionized water for 5 minutes respectively, then placed on a heating platform for drying at 100° C. for 10 minutes, and after cooling, a tape for spin coating mask is pasted in the middle area.

[0042] Step S2, placing the highly doped silicon substrate treated in step S1 into a UV ozone machine for treatment for 30 minutes; then adsorbing the highly doped silicon substrate onto a spin coater, dripping an intrinsic DPPT-TT / DCB mixed solution onto the surface for spin coating to prepare an organic semiconductor layer 4, wherein the mixed solution here is a DPPT-TT / DCB solution with a concentration of 5 mg / ml; the initial speed of the spin coating is 0 rpm, and it is accelerated to 500 rpm at an acceleration of 200 rpm / s, and the acceleration and uniform speed time of this stage last for a total of 10 seconds; then it is accelerated to 1500 rpm at an acceleration of 500 rpm / s, and the acceleration and uniform speed time of this stage last for a total of 60 seconds; then it is decelerated to 0 rpm at an acceleration of 500 rpm / s, and the deceleration and stop time of this stage last for a total of 5 seconds; then it is heated at 80°C for 5 minutes, and then annealed at 150°C for 1 hour.

[0043] Step S3, tearing off the tape to remove the DPPT-TT in the middle area.

[0044] Step S4, ultrasonically treat the anode mask in alcohol and deionized water for 3 minutes, cycle for 3 times, then blow dry with nitrogen, and adsorb it on the spin-coated high-doped silicon substrate. The anode mask is made of a metal mask made of stainless steel with a thickness of 0.1 mm. Put it into the evaporator and evaporate 80 nm of metal Cu, wherein 5nm of metal Cu was deposited at a speed of 70nm of Cu metal was deposited at a speed of 5 nm of metal Cu is evaporated at a speed of 1000 to form an anode 3, and an indium sheet of appropriate size is adhered to the scraping area as a cathode 4.

[0045] like Figure 1 FIG. 1 is a structural diagram of an organic-inorganic heterojunction diode based on silicon and DPPT-TT in the present invention, as shown in FIG. Figure 2 is with Figure 1 The corresponding construction process flow chart is as follows: Figure 3 Shown is a physical picture of a device prepared by the process technology of the present invention;

[0046] Comparative Example 1

[0047] Comparative Example 1 provides a longitudinal SBD of a common structure, such as Figure 4 As shown, the preparation process of Comparative Example 1 includes the following four steps:

[0048] Step S1, a glass substrate 8 with a thickness of 0.5 mm is ultrasonically treated in alcohol and deionized water for 5 min, and then placed on a heating table for drying at 100°C for 10 min, and then a mask is adsorbed on the glass substrate. The mask is made of a metal mask and the metal mask is made of stainless steel with a thickness of 0.1 mm. The glass substrate is placed in an evaporator to evaporate 5 nm of metal Ni and 40 nm of metal Among them, 5nm of metal Ni is evaporated at a speed of 100nm, and then 5nm of metal is evaporated at a speed of 100nm. Then, 30nm of metal is evaporated at a speed of Finally, 5nm of metal was evaporated at a speed of Thus, the metal cathode 5 is prepared.

[0049] Step S2, placing the glass substrate treated in step S1 into an ultraviolet ozone machine for 30 minutes; then adsorbing the glass substrate onto a spin coater, dripping an intrinsic DPPT-TT / DCB mixed solution onto the surface and spin coating to prepare an organic semiconductor layer 6, wherein the mixed solution here is a DPPT-TT / DCB solution with a concentration of 5 mg / ml; the initial speed of the spin coating is 0 rpm, and it is accelerated to 500 rpm at an acceleration of 200 rpm / s, and the acceleration and uniform speed time of this stage last for a total of 10 seconds; then it is accelerated to 1500 rpm at an acceleration of 500 rpm / s, and the acceleration and uniform speed time of this stage last for a total of 60 seconds; then it is decelerated to 0 rpm at an acceleration of 500 rpm / s, and the deceleration and stop time of this stage last for a total of 5 seconds; then it is heated at 80°C for 5 minutes, and then annealed at 150°C for 1 hour.

[0050] Step S3, ultrasonically treat the anode mask in alcohol and deionized water for 3 minutes, cycle for 3 times, then blow dry with nitrogen, and adsorb it on the glass substrate after spin coating. The anode mask is made of a metal mask and the metal mask is made of stainless steel with a thickness of 0.1 mm. Put it into the evaporator and evaporate 80 nm of metal Cu, where 5nm of metal Cu was deposited at a speed of 70nm of Cu metal was deposited at a speed of 5 nm of metal Cu was evaporated at a speed of , to form an anode 7.

[0051] Compared with ordinary DPPT-TT-based SBDs, organic-inorganic heterojunction diodes based on silicon and DPPT-TT introduce new current paths due to the interface effect of the heterojunction, and the additional tunneling current improves the forward conduction current of the device to a certain extent.

[0052] The organic-inorganic heterojunction diode based on silicon and DPPT-TT prepared in Example 1 was placed on a probe station for testing. The ambient temperature was increased by 10 degrees Celsius every 20 minutes and the test was repeated. Figure 5 The output characteristic curve is shown.

[0053] from Figure 5 It can be seen that the heterojunction prepared by the present invention has the characteristic of bidirectional conduction, in which the temperature dependence of the forward current and the reverse current is quite different. In order to further understand the principle, the reverse saturation current of each curve is extracted, such as formula (3):

[0054]

[0055] Where I0 represents the reverse saturation current, q is the electron charge, n is the ideal factor, k is the Boltzmann constant, and t is the temperature.

[0056] From this, we can get the relationship between the reverse saturation current and temperature in the two conduction directions, such as Figure 6 As shown. Where is- represents the reverse saturation current when the interface close to the cathode is turned on, and is+ represents the reverse saturation current when the interface close to the anode is turned on.

[0057] from Figure 5 and Figure 6 It can be observed that the heterojunction diode prepared by the present invention exhibits obvious bidirectional conduction characteristics. This means that the diode can not only effectively conduct when forward biased, but also maintain a certain degree of conductivity when reverse biased.

[0058] In terms of temperature dependence, the performance gap between the forward current and the reverse current is large, indicating that the device's conductive mechanism and performance are affected to varying degrees under different temperature environments. Figure 6 The trend of the reverse saturation current changing with temperature can be intuitively seen in the figure. This trend shows that the reverse saturation current in the forward and reverse directions exhibits completely different temperature dependences. As the temperature rises, the increase in the reverse saturation current may be related to the increase in carrier concentration and the change in the conductive mechanism of the material itself. The reverse saturation current with low temperature dependence provides an important basis for the tunnel recombination current in semiconductors.

[0059] The vertical SBD of the common structure provided in Comparative Example 1 is placed on a probe station for testing, and the output characteristic curve is as follows: Figure 7 shown.

[0060] Figure 5 and Figure 7 The comparison can also intuitively show the effect of the electrode modification scheme based on silicon and DPPT-TT organic-inorganic heterojunction proposed in the present invention.

[0061] In general, organic-inorganic heterojunction diodes based on silicon and DPPT-TT have greatly improved the conductivity of the device due to their unique structural properties. This makes it have a wider application prospect and research value in future electronic devices and related applications. With the in-depth research and optimization of these devices, we can expect them to emerge in the fields of communications, sensor technology and new energy. For example, in power management and communication equipment, diodes can be used to protect communication lines to prevent equipment damage caused by excessive current, and can also be used in modems to adjust the amplitude and direction of signals. Using bidirectional conducting diodes at the power input can protect sensitive electronic components from transient overvoltages, etc.

Claims

1. A bidirectionally conductive vertical structure diode, comprising: an anode, a cathode and an organic-inorganic heterojunction; the region covered by the anode is a P-type semiconductor layer of the heterojunction, which is composed of a DPPT-TT film formed by coating an undoped intrinsic DPPT-TT solution; the region covered by the cathode is an N-type semiconductor layer of the heterojunction, which is a 10 -19 (cm -3 ) silicon wafer with phosphorus atoms; the anode uses copper as the contact material; the cathode is an indium sheet.

2. The bidirectionally conductive vertical structure diode according to claim 1, characterized in that: The solute of the DPPT-TT solution is DCB and the concentration of DPPT-TT in the DPPT-TT / DCB solution is in the range of 1 to 15 mg / ml.

3. The method for manufacturing the bidirectionally conductive vertical structure diode according to claim 2, characterized in that: The preparation method comprises the following steps: ultrasonically cleaning the highly doped silicon wafer, pasting a tape for spin coating mask, spin coating a DPPT-TT / DCB solution onto the surface to prepare an organic semiconductor layer, then heating at 80°C for 5 minutes, and then annealing at 150°C for 1 hour; tearing off the tape to remove the DPPT-TT material in the middle area, and adhering an indium sheet to the middle area, that is, directly adhering the indium sheet to the highly doped silicon wafer in the middle area; and making an anode on the organic semiconductor layer.

4. The method according to claim 3, characterized in that: The concentration of DPPT-TT in the DPPT-TT / DCB solution is 5 mg / ml.

5. The method according to claim 4, characterized in that: The spin coating parameters of the DPPT-TT / DCB solution were set as follows: the initial speed of the spin coating was 0 rpm, and it was accelerated to 500 rpm at an acceleration of 200 rpm / s, and the acceleration and constant speed time of this stage lasted for a total of 10 s; then it was accelerated to 1500 rpm at an acceleration of 500 rpm / s, and the acceleration and constant speed time of this stage lasted for a total of 60 s; then it was decelerated to 0 rpm at an acceleration of 500 rpm / s, and the deceleration and stop time of this stage lasted for a total of 5 s.

6. The method according to claim 3, characterized in that: The anode is manufactured by evaporation or magnetron sputtering.

7. The method according to claim 6, characterized in that: The anode is made by evaporation, and the steps include: first 5nm of metal Cu was evaporated at a speed of 70nm of Cu metal was deposited at a speed of 5 nm of metal Cu was evaporated at a rate of , and finally a metal Cu anode with a thickness of 80 nm was formed by evaporation.

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