Bidirectional conduction longitudinal structure diode and manufacturing method thereof

Abstract

The application 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 application has an anode, a cathode and an organic-inorganic heterojunction. 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. The area covered by the cathode is an N-type semiconductor layer of the heterojunction, which is a silicon wafer doped with 10 19 (cm ‑3 ) phosphorus atoms. The anode uses copper as a contact material, and the cathode is an indium wafer. By introducing a new tunnel recombination current mode, the charge transport capacity is enhanced. This new heterojunction structure effectively improves the injection and transmission process of carriers at the electrode, significantly reducing the contact resistance. This electrode modification scheme not only improves the conductivity of the device, but also improves the overall energy transmission efficiency.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device technology and relates to a bidirectional vertical structure diode and its fabrication method. Background Technology

[0002] A bidirectional diode is a diode that conducts current in both directions, allowing it to conduct current under both forward and reverse voltages. This type of diode combines the unidirectional conduction characteristics of a regular diode with the bidirectional protection characteristics of a bidirectional constant current diode such as a Zener diode.

[0003] A bidirectional diode has a structure similar to a regular diode, but its internal design allows it to conduct current under both forward and reverse voltage conditions. It is typically made of silicon and uses a PN junction to achieve bidirectional conductivity. When a forward voltage is applied, the bidirectional diode behaves like a regular diode, allowing current to flow from the positive to the negative terminal, thus providing forward conduction. Under reverse voltage conditions, the bidirectional diode exhibits the characteristics of 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 a crucial role in electronic circuits due to their unique bidirectional conductivity, especially in applications requiring both bidirectional conduction and protection. For example, bidirectional diodes are used in power management circuits for voltage regulation, current limiting, and overvoltage protection, improving circuit stability and safety. In communication equipment, bidirectional diodes are commonly used to protect lines, interfaces, and other electronic components from damage caused by voltage surges, electrostatic discharge, etc. In automotive electronic systems, bidirectional diodes can protect onboard electronic devices from equipment failures caused by electromagnetic interference, overvoltage, and other factors. In industrial automation and control systems, bidirectional diodes are widely used to protect critical equipment such as PLCs, sensors, and actuators, ensuring system stability and reliability.

[0005] In recent years, organic semiconductors have developed rapidly due to their wide range of applications, mainly thanks to the lightweight and flexibility of organic materials, which give them unparalleled advantages in various applications. For example, organic semiconductor materials have broad application prospects in wearable devices, flexible electronics, and large-area displays. However, despite their outstanding performance in these areas, organic semiconductors generally have lower electron and hole mobilities compared to inorganic semiconductors, which limits the switching speed and response time of devices. Specifically, low mobility limits the performance of organic semiconductor devices in high-frequency applications, failing to meet the requirements of fast switching and efficient signal processing. In addition, most organic semiconductor devices lack matched ohmic contact electrodes in their design, resulting in excessively high contact resistance. This high contact resistance not only affects the conductivity of the device but also limits the effective injection of charge 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 a significant problem, further limiting the efficiency of charge carrier transport and leading to significant energy loss. This energy loss not only affects the operating efficiency of the device but may also lead to performance degradation after prolonged use. Therefore, improving the electrical performance of organic semiconductor devices, especially reducing contact resistance and increasing energy transfer efficiency, is an important direction in current organic electronics research.

[0006] In summary, the low carrier density and mobility of organic materials are among the main factors limiting the performance of organic devices. These organic materials typically exhibit relatively low electrical conductivity, which directly leads to a decrease in energy transfer efficiency within the device. In traditional organic devices, the carrier concentration in the electrode region is low. This low carrier concentration not only increases the contact resistance between the electrode and the organic material but also limits the overall conductivity of the device. Summary of the Invention

[0007] To address the aforementioned technical problems, this application combines organic semiconductors and highly doped silicon to construct a novel organic-inorganic heterojunction for diode fabrication. A bidirectional, vertically oriented diode based on an organic-inorganic heterojunction constructed from silicon and DPPT-TT is proposed, enhancing charge transport capability by introducing a novel tunnel recombination current mode. This novel heterojunction structure effectively improves carrier injection and transport at the electrodes, significantly reducing contact resistance. This electrode modification scheme not only improves device conductivity but also enhances overall energy transfer efficiency.

[0008] In a first aspect, the present invention provides a bidirectional, vertically oriented diode comprising:

[0009] Anode, cathode, and organic-inorganic heterojunction;

[0010] The anode-covered region is a heterojunction P-type semiconductor layer, which is composed of a DPPT-TT film formed by coating with an undoped intrinsic DPPT-TT solution; preferably, 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.

[0011] The cathode-covered region is an N-type semiconductor layer of a heterojunction, which is doped with 10... -19 (cm -3 Silicon wafers containing phosphorus atoms.

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

[0013] The cathode is an indium sheet.

[0014] Secondly, the present invention provides a method for manufacturing the above-mentioned bidirectional longitudinal structure diode, the method comprising the steps of:

[0015] After ultrasonic cleaning of the highly doped silicon wafer, adhesive tape for spin-coating mask is applied, and DPPT-TT / DCB solution is spin-coated onto the surface to form an organic semiconductor layer. Then, it is heated at 80°C for 5 minutes and annealed at 150°C for 1 hour. After removing the DPPT-TT material in the middle area by peeling off the adhesive tape, an indium wafer is attached to this middle area, that is, the indium wafer is directly attached to the highly doped silicon wafer in the middle area. An anode is then fabricated 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 spin-coating speed is 0 rpm, accelerating to 500 rpm at an acceleration of 200 rpm / s, with the acceleration and constant speed period lasting for 10 s; then accelerating to 1500 rpm at an acceleration of 500 rpm / s, with the acceleration and constant speed period lasting for 60 s; and then decelerating to 0 rpm at an acceleration of 500 rpm / s, with the deceleration and stopping period lasting for 5 s.

[0017] Preferably, the anode is fabricated by vapor deposition or magnetron sputtering. It should be noted that the anode is fabricated using a metal mask designed with layout design software according to different circuit structures, resulting in a corresponding shape. More preferably, the anode is fabricated by vapor deposition, and the fabrication steps include: firstly... 5nm of metallic Cu was deposited at a speed of [speed not specified], followed by [processing / deposition]. 70nm of metallic Cu was deposited at a speed of [speed not specified], followed by [finally / continuously / A 5nm thick Cu metal anode is deposited at a speed of [speed not specified], and finally a Cu metal anode with a thickness of 80nm is formed by evaporation.

[0018] Technical Principle: Due to lattice mismatch, a large number of interface states exist between silicon and DPPT-TT. These interface states, like surface states, may contain both partial acceptors and partial donors. To achieve equilibrium, the materials on both sides of the interface release electrons to the acceptors. If the concentration of interface states is high enough, two positively charged depletion layers are generated. The sum of their charges is equal to and opposite in polarity to the charge of the interface state monolayer. They are spatially confined within an extremely thin layer, the "interface," and exist in an exceptionally narrow energy range. This characteristic keeps the Fermi levels on both sides unchanged under an applied voltage. Furthermore, their total trapping cross-section is so large that all electrons crossing the interface are trapped and re-emitted by these states. In the heterojunction diode fabricated in this invention, the influence of the interface states on both sides can be replaced by a metal sandwich layer, which forms a metal-semiconductor contact with both semiconductors. The interface can be equivalent to two anti-tandem Schottky diodes, where heavy doping on the silicon side induces tunneling in the corresponding depletion layer barrier.

[0019] For a single, ideal diode, the desired parameters can be easily extracted from its output characteristic curve. However, real-world experiments often involve the combined effects of various factors. For organic-inorganic heterojunction diodes based on silicon and DPPT-TT, not only are there reverse-series Schottky diodes, but the variable bulk resistance also adds many challenges to the experiment. Therefore, the differential method was used to analyze its current-voltage characteristics, which can provide more accurate information about this complex heterojunction structure. A single diode can be considered an ideal diode, with a shunt resistance R... sh It consists of a series resistor R, as shown in equation (1).

[0020]

[0021] Generally, R is taken. sh V is positive infinity j =VI j R, then we can obtain equation (2):

[0022]

[0023] This method can improve measurement sensitivity and directly obtain data from... The slope of the straight line is used to obtain the series resistance R, thereby eliminating the influence of changes in volume resistance.

[0024] The silicon layer region and the cathode have been verified to be in ohmic contact. The silicon layer region and the DPPT-TT region are heterojunction interfaces. New tunnel recombination currents are introduced through the silicon layer region with high doping concentration to achieve a larger forward conduction current under the same voltage.

[0025] Beneficial Effects: The bidirectional vertically structured diode provided by this invention combines organic semiconductor DPPT-TT and highly doped silicon to form an organic-inorganic heterojunction based on silicon and DPPT-TT. The resulting diode exhibits low electrode contact resistance, allowing for more efficient injection of charge carriers into the organic material. Consequently, the device displays a higher on-state current. This improvement not only enhances the device's operating efficiency but also lays the foundation for its use in high-performance applications. For example, in photoelectric conversion and energy storage systems, increased current carrying capacity can significantly improve overall efficiency, making the device more competitive. Furthermore, another potential advantage of silicon and DPPT-TT-based organic-inorganic heterojunction diodes is their flexibility within heterogeneous material systems. By precisely controlling the ratio and interface structure of the organic and inorganic components, device performance can be further optimized to achieve higher efficiency and stability.

[0026] Overall, the organic-inorganic heterojunction diodes based on silicon and DPPT-TT improve charge transport capability by solving the contact resistance problem present in traditional organic devices, marking an important advancement in the field of organic electronic devices. Attached Figure Description

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

[0028] Figure 2 This is a flowchart of the organic-inorganic heterojunction diode based on silicon and DPPT-TT in this invention;

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

[0030] Figure 4 This is a flowchart of the preparation process of the longitudinal SBD based on DPPT-TT in Comparative Example 1 of this invention;

[0031] Figure 5 This is a graph showing the output characteristics of the organic-inorganic heterojunction diode based on silicon and DPPT-TT at different temperatures in this invention.

[0032] Figure 6 This is the curve showing the change of reverse saturation current with temperature for the organic-inorganic heterojunction diode based on silicon and DPPT-TT in this 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 Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but the invention is not limited to these embodiments. The invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention. To provide the public with a thorough understanding of the invention, specific details are described in detail in the following embodiments, but those skilled in the art will fully understand the invention even without these details.

[0035] In the description of this invention, it should be noted that the terms "middle," "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0036] The sources of the reagent kit materials and equipment used in the following examples and test cases are shown below:

[0037] DPPT-TT: Nanjing Zhiyan Technology Co., Ltd.; Dichlorobenzene (DCB) solution: SigmA-Aldrich; Phosphorus doping, concentration 10. 19 (cm -3 The N-type silicon wafers were purchased from Guangzhou Fangdao Semiconductor Co., Ltd.

[0038] Example 1

[0039] Example 1 illustrates the fabrication process of this invention using the fabrication of an organic-inorganic heterojunction diode based on silicon and DPPT-TT as an example; 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 has a doping concentration of 10-10. 19 (cm -3 The substrate is an N-type silicon substrate; the anode 2 is a copper electrode and the cathode is indium; the organic semiconductor layer 4 is an intrinsic organic material DPPT-TT thin film.

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

[0041] Step S1: Sonicate a 0.5mm thick highly silicon-doped substrate in alcohol and deionized water for 5 minutes each, then place it on a heating table and dry it at 100°C for 10 minutes. After cooling, apply tape for spin coating mask to the middle area.

[0042] Step S2: The highly silicon-doped substrate treated in Step S1 is placed in an ultraviolet ozone generator for 30 minutes. Then, the highly silicon-doped substrate is adsorbed onto a spin coater, and an intrinsic DPPT-TT / DCB mixed solution is dropped onto the surface for spin coating to prepare an organic semiconductor layer 4. The mixed solution here is a DPPT-TT / DCB solution with a concentration of 5 mg / ml. The initial spin coating speed is 0 rpm, which is accelerated to 500 rpm at an acceleration of 200 rpm / s. The acceleration and constant speed time in this stage lasts for 10 seconds. Then, the acceleration is accelerated to 1500 rpm at an acceleration of 500 rpm / s. The acceleration and constant speed time in this stage lasts for 60 seconds. Then, the acceleration is decelerated to 0 rpm at an acceleration of 500 rpm / s. The deceleration and stopping time in this stage lasts for 5 seconds. Then, the substrate is heated at 80°C for 5 minutes, and then annealed at 150°C for 1 hour.

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

[0044] Step S4: The anode mask is ultrasonically treated with alcohol and deionized water for 3 minutes each, repeated 3 times. After drying with nitrogen, it is adsorbed onto the spin-coated highly doped silicon substrate. The anode mask is made of stainless steel and has a thickness of 0.1 mm. It is then placed in a vapor deposition apparatus to deposit 80 nm of Cu metal. 5nm of metallic Cu was deposited at a speed of [speed not specified], followed by [processing / deposition]. 70nm of metallic Cu was deposited at a speed of [speed not specified], followed by [finally / continuously / A 5nm layer of metallic Cu is deposited at a speed of evaporation to form the anode 3, and an indium sheet of appropriate size is attached to the coated area as the cathode 4.

[0045] like Figure 1 The diagram shown is a structural diagram of an organic-inorganic heterojunction diode based on silicon and DPPT-TT according to the present invention. Figure 2 Is with Figure 1 The corresponding manufacturing process flow chart, such as Figure 3 The image shown is a physical diagram of the device fabricated using the process described in this invention.

[0046] Comparative Example 1

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

[0048] Step S1: The 0.5mm thick glass substrate 8 is ultrasonically treated with alcohol and deionized water for 5 minutes each, then dried at 100°C for 10 minutes on a heating stage. A metal mask (stainless steel) with a thickness of 0.1mm is then deposited onto the glass substrate in a vapor deposition apparatus to deposit 5nm of Ni and 40nm of metal. In this process, 5 nm of metallic Ni is deposited at a certain velocity, and then another 5 nm of metallic Ni is deposited at a certain velocity. Then, 30nm of metal was deposited at a rate of [missing information]. Finally, 5nm of metal was deposited at a speed of [missing information]. Thus, a metal cathode 5 is prepared.

[0049] Step S2: The glass substrate treated in step S1 is placed in an ultraviolet ozone generator for 30 minutes; then the glass substrate is adsorbed onto a spin coater, and an intrinsic DPPT-TT / DCB mixed solution is dropped onto the surface for spin coating to prepare an organic semiconductor layer 6. The mixed solution here is a DPPT-TT / DCB solution with a concentration of 5 mg / ml; the initial spin coating speed is 0 rpm, which is accelerated to 500 rpm at an acceleration of 200 rpm / s, and the acceleration and constant speed period lasts for 10 seconds; then it is accelerated to 1500 rpm at an acceleration of 500 rpm / s, and the acceleration and constant speed period lasts for 60 seconds; then it is decelerated to 0 rpm at an acceleration of 500 rpm / s, and the deceleration and stopping period lasts for 5 seconds; then it is heated at 80°C for 5 minutes, and then annealed at 150°C for 1 hour.

[0050] Step S3: The anode mask is ultrasonically treated with alcohol and deionized water for 3 minutes each, repeated 3 times. After drying with nitrogen, it is adsorbed onto the spin-coated glass substrate. The anode mask is made of stainless steel and has a thickness of 0.1 mm. It is then placed in a vapor deposition apparatus to deposit 80 nm of Cu metal. 5nm of metallic Cu was deposited at a speed of [speed not specified], followed by [processing / deposition]. 70nm of metallic Cu was deposited at a speed of [speed not specified], followed by [finally / continuously / A 5nm layer of metallic Cu is deposited at a speed of evaporation to form an anode 7.

[0051] Compared to ordinary SBDs based on DPPT-TT, 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 some extent.

[0052] The silicon- and DPPT-TT-based organic-inorganic heterojunction diode prepared in Example 1 was tested on a probe stage. The ambient temperature was increased by 10 degrees Celsius every 20 minutes, and the test was repeated to obtain the following results: Figure 5 The output characteristic curve is shown.

[0053] from Figure 5 As can be seen from the above, the heterojunction prepared by this invention has bidirectional conduction characteristics, wherein the temperature dependence of the forward current and the reverse current differs significantly. To further understand the underlying principle, the reverse saturation current of each curve was extracted, as shown in equation (3):

[0054]

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

[0056] From this, we can obtain the relationship between the reverse saturation current and temperature in the two conduction directions, such as... Figure 6 As shown in the figure. Here, is- represents the reverse saturation current when conduction occurs near the cathode interface, and is+ represents the reverse saturation current when conduction occurs near the anode interface.

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

[0058] Regarding temperature dependence, the significant difference between forward and reverse current performance indicates that the device's conductivity mechanism and performance are affected to varying degrees under different temperature conditions. Figure 6 The trend of reverse saturation current with temperature can be clearly observed. This trend shows that the reverse saturation current exhibits distinctly different temperature dependencies in the forward and reverse directions. The increase in reverse saturation current with increasing temperature may be related to the increase in carrier concentration and changes in the conductivity mechanism of the material itself. The low temperature dependence of the reverse saturation current provides important evidence for tunnel recombination current in semiconductors.

[0059] The longitudinal SBD with the ordinary structure provided in Comparative Example 1 is placed on the probe stage for testing, and the output characteristic curve is as follows: Figure 7 As shown.

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

[0061] In summary, silicon-based and DPPT-TT-based organic-inorganic heterojunction diodes, with their unique structural properties, significantly improve the conductivity of devices. This gives them broader application prospects and research value in future electronic devices and related applications. With further research and optimization of these devices, we can expect them to emerge in fields such as communications, sensor technology, and new energy. For example, in power management and communication equipment, diodes can be used to protect communication lines from damage caused by excessive current, and they can also be used in modems to adjust the amplitude and direction of signals. Using bidirectional diodes at the power input can protect sensitive electronic components from transient overvoltages.

Claims

1. A bidirectional, vertically oriented diode comprising: an anode, a cathode, and an organic-inorganic heterojunction; wherein the anode-covered region is a P-type semiconductor layer of the heterojunction, which is composed of a DPPT-TT film formed by coating with an undoped intrinsic DPPT-TT solution; and the cathode-covered region is an N-type semiconductor layer of the heterojunction, which is doped with 10... -19 (cm -3 A silicon wafer with phosphorus atoms; the anode uses copper as the contact material; the cathode is an indium wafer; In the addition of 10 -19 (cm -3 A DPPT-TT film is formed by coating both sides of the upper surface of a silicon wafer with phosphorus atoms. -19 (cm -3 A cathode is attached to the middle region of the upper surface of a silicon wafer containing phosphorus atoms; the anode is deposited on the upper surface of the DPPT-TT films on both sides.

2. The bidirectional longitudinal structure diode as described in claim 1, characterized in that, The solute in the DPPT-TT solution is dichlorobenzene (DCB), and the concentration of DPPT-TT in the DPPT-TT / DCB solution ranges from 1 to 15 mg / ml.

3. A method for fabricating a bidirectional longitudinal structure diode as described in claim 2, characterized in that, The manufacturing method includes the step of: adding 10 -19 (cm -3 After ultrasonic cleaning of the silicon wafer containing phosphorus atoms, adhesive tape for spin-coating mask is applied. DPPT-TT / DCB solution is spin-coated onto the surface to form an organic semiconductor layer. The layer is then heated at 80°C for 5 minutes, followed by annealing at 150°C for 1 hour. After removing the tape and discarding the DPPT-TT material in the central area, an indium wafer is adhered to this central area, i.e., the indium wafer is directly adhered to the doped 10 in the central area. -19 (cm -3 On a silicon wafer containing phosphorus atoms; an anode is fabricated on the organic semiconductor layer.

4. The manufacturing method as described in claim 3, characterized in that, The concentration of DPPT-TT in the DPPT-TT / DCB solution is 5 mg / ml.

5. The manufacturing method as described in claim 4, characterized in that, The spin coating parameters for the DPPT-TT / DCB solution were set as follows: the initial spin coating speed was 0 rpm, accelerated to 500 rpm at 200 rpm / s, and the acceleration and constant speed period lasted for 10 s; then accelerated to 1500 rpm at 500 rpm / s, and the acceleration and constant speed period lasted for 60 s; then decelerated to 0 rpm at 500 rpm / s, and the deceleration and stopping period lasted for 5 s.

6. The manufacturing method as described in claim 3, characterized in that, The anode is manufactured by vapor deposition or magnetron sputtering.

7. The manufacturing method as described in claim 6, characterized in that, The anode is fabricated by vapor deposition, and the fabrication steps include: first, depositing 5 nm of metallic Cu at a speed of 0.1 Å / s, then depositing 70 nm of metallic Cu at a speed of 0.5 Å / s, and finally depositing 5 nm of metallic Cu at a speed of 0.1 Å / s, thereby forming a metallic Cu anode with a thickness of 80 nm.

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