A high quality silicon nitride dielectric passivation layer processing process based on supercritical fluid

Abstract

The application discloses a high-quality silicon nitride medium passivation layer processing technology based on supercritical fluid, which vertically places a substrate sample with a Si3N4 medium passivation layer into a reaction container; fills deionized water into the reaction container and seals the reaction container; controls pressure, fills CO2 or N2O supercritical gas into the reaction container; performs temperature and pressure increasing treatment on the reaction container, then keeps pressure, so that the inside of the reaction container is in a supercritical state; keeps the supercritical state, performs pressure decreasing treatment on the reaction container, and keeps the supercritical treatment condition at 20-22 MPa; after the reaction is finished, performs temperature decreasing treatment on the reaction container, and takes out the reaction container when the pressure is reduced to atmospheric pressure. The application passivates the traps and interface states in the Si3N4 medium layer under low temperature and high pressure, is simple and convenient to operate, avoids problems caused by a high-temperature annealing process, and thus improves the quality of the Si3N4 medium layer, enhances the breakdown electric field, and reduces the leakage current density.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor Si3N4 passivation layer materials, and particularly relates to a high-quality Si3N4 dielectric passivation layer processing process based on supercritical fluid and application thereof. BACKGROUND

[0002] In order to obtain high-quality Si3N4 dielectric passivation layer and improve the reliability and stability of devices, researchers have made various attempts. At present, the heat treatment after depositing the silicon nitride film is a main method for improving the performance of silicon nitride.

[0003] For example, Reynes et al. heat-treated the silicon nitride film with low H content at a temperature of 1200K, and the results showed that the stability of the silicon nitride film with high H content deteriorated; Z Lu et al. deposited the silicon nitride film by using the remote plasma enhanced chemical vapor deposition (RPECVD) method, and heat-treated the film at a temperature of 400-900℃, tested and researched the change of H content in the silicon nitride film after the rapid heat treatment by using the infrared spectrum analysis method, and pointed out that the H content in the silicon nitride film and the content of Si-H bond and N-H bond depend on the flow ratio of the reaction gas (NH3, SiH4), the H in the silicon nitride film will overflow out of the film in the form of H2 and NH3 after the rapid heat treatment, with the increase of the annealing temperature, the H content in the film will decrease and the content of Si-N bond will be improved, and the electrical characteristics of the silicon nitride film after the heat treatment at a temperature of 900℃ are also improved; A.E.T Kuiper treated the silicon nitride film in RHO2102 at a high temperature of 1273K for 6h, and found that there was only an oxide layer with a thickness of 20nm on the surface of the silicon nitride film, which indicated that the high-temperature oxidation resistance of the silicon nitride film is excellent, but the high-temperature oxidation resistance will deteriorate with the increase of the H content. Although the heat treatment is effective in improving the performance of the silicon nitride film and reducing the leakage current, these methods will introduce foreign atoms into the silicon nitride film, causing the generation of external defects and the reduction of reliability.

[0004] In addition, the high-temperature heat treatment can reduce the stability of the device and can cause a secondary parasitic oxidation effect. Therefore, it is necessary to find a low-temperature method to obtain a high-quality passivation layer.

[0005] With the miniaturization, intelligentization and increasing integration of integrated circuits, the surface properties of the semiconductor have a greater and greater influence on the overall performance of the device. On the other hand, the material is easily mechanically damaged in the process, the surface of the chip exposed to the air will form a natural oxide layer, and the cleaning process is easy to cause pollution on the surface, etc. These external factors will cause serious surface effects and affect or even damage the overall performance of the device. Therefore, finding a passivation film with excellent performance has always been an important task of semiconductor technology.

[0006] Among the many passivation layer materials, silicon nitride film has large dielectric constant, good compactness, strong resistance to impurity diffusion and water vapor permeation, and good mechanical and insulating properties, as well as oxidation resistance, corrosion resistance and abrasion resistance. It has obvious advantages in resistance to impurity diffusion and water vapor permeation, so silicon nitride film is one of the most promising surface passivation materials in semiconductor integrated circuits.

[0007] Due to these advantages, silicon nitride film has been widely used in the fields of integrated circuits, micro-mechanical electronics, solar cells and display devices, such as GaN HEMTs devices, TFT thin film transistors, Si3N4 single-layer grating couplers. However, silicon nitride film also has its shortcomings, the most prominent of which is that the interface state density between silicon nitride film and active layer (single crystal silicon or polycrystalline silicon) is high, and the silicon nitride passivation layer has low breakdown field strength and high leakage current. The quality of the film becomes the main factor limiting the use of silicon nitride. Therefore, how to obtain high-quality Si3N4 passivation layer has become the focus of research. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a high-quality silicon nitride dielectric passivation layer processing technology based on supercritical fluid, which is simple to operate and does not require high temperature, and provides a method for preparing a high-quality passivation layer and a low-leakage-current silicon nitride film, in view of the problems of low breakdown voltage and large gate leakage current of the current Si3N4 dielectric passivation layer.

[0009] The technical scheme adopted by the present application is as follows:

[0010] A high-quality Si3N4 dielectric passivation layer processing technology based on supercritical fluid, comprising the following steps:

[0011] S1, vertically placing a substrate sample with a Si3N4 dielectric passivation layer into a reaction container;

[0012] S2, filling deionized water into the reaction container, and then sealing the reaction container;

[0013] S3, controlling the pressure, and filling CO2 or N2O supercritical gas into the sealed reaction container of step S2;

[0014] S4, performing temperature and pressure increasing treatment on the reaction container filled with CO2 or N2O supercritical gas in step S3, and then maintaining the pressure, so that the inside of the reaction container is in a supercritical state;

[0015] S5, maintaining the supercritical state treatment of step S4, and performing pressure reduction treatment on the reaction container, and maintaining the supercritical treatment condition at 20-22 MPa;

[0016] S6, after the reaction in step S5 is completed, the reaction container is cooled, and when the pressure is reduced to atmospheric pressure, the reaction container is removed.

[0017] Specifically, in step S2, 0.5-2 mL of deionized water is filled into the reaction container, and then the reaction container is sealed.

[0018] Specifically, in step S3, the initial pressure of the reaction container is 10-12 MPa, and then the pressure of the reaction container is controlled to be 15-50 MPa, and CO2 or N2O is filled.

[0019] Specifically, in step S4, the temperature of the reaction container is increased from 25°C to 120-150°C, the pressure is increased to 15-50 MPa, and the pressure holding time is 1-60 min.

[0020] Further, the heating rate of the reaction container is 1-10°C / min.

[0021] Specifically, in step S5, the temperature for pressure reduction treatment of the reaction container is 120-150°C.

[0022] Specifically, in step S5, the holding time under supercritical treatment conditions is 1-2 h.

[0023] Specifically, in step S6, the temperature for cooling treatment is 30-60°C.

[0024] Specifically, the breakdown field of the Si3N4 dielectric passivation layer is 5.02-6.54 MV / cm, and the leakage current density of the silicon nitride is 8x10 -7 -2x10 -6 A1cm 2 .

[0025] Compared with the prior art, the present application has at least the following beneficial effects:

[0026] The present application is a high-quality Si3N4 dielectric passivation layer treatment process based on supercritical fluid, which improves the Si3N4 dielectric passivation layer under high pressure, is simple to operate, effectively reduces the process temperature, improves the quality of the Si3N4 dielectric passivation layer, and makes CO2 or N2O reach a supercritical fluid state through low temperature and high pressure, the supercritical fluid dissolves water molecules, and through its superior penetration ability, it brings them into the dielectric layer, thereby passivating the defects and trap charges of the Si3N4 dielectric layer, effectively improving the quality of the Si3N4 dielectric layer.

[0027] Further, 0.5 mL-2 mL of deionized water, i.e. 0.3-1.3% by volume, is added to the reaction container, so that the deionized water fully participates in the entire supercritical reaction process without waste.

[0028] Further, the initial pressure of the reaction container is 10-12 MPa, so that the equipment is based on the pressure to carry out the corresponding pressure process, to ensure that the reaction is rapid and effective. Then control the pressure of the reaction container to be 15-50 MPa, fill CO2 or N2O, let the deionized water and CO2 or N2O dissolve fully, while ensuring that the whole system can reach the supercritical state.

[0029] Further, the temperature of the reaction container is increased from 25℃ to 120-150℃, and the pressure is increased to 15-50 MPa, and the pressure holding time is 1-60 min, which ensures that the reaction container is in a supercritical temperature and supercritical pressure, and the supercritical fluid state is not broken in the reaction time.

[0030] Further, the temperature of the reaction container is increased from 25℃ to 120-150℃, and the pressure is increased to 15-50 MPa, and the pressure holding time is 1-60 min, which ensures that the reaction container is in a supercritical temperature and supercritical pressure, and the supercritical fluid state is not broken in the reaction time.

[0031] Further, the temperature of the reaction container is increased from 25℃ to 120-150℃, and the pressure is increased to 15-50 MPa, and the pressure holding time is 1-60 min, which ensures that the reaction container is in a supercritical temperature and supercritical pressure, and the supercritical fluid state is not broken in the reaction time.

[0032] Further, the supercritical treatment condition is maintained for 1-2h, so that the deionized water and CO2 can be fully dissolved in the time.

[0033] Further, the temperature of the reaction container is increased from 25℃ to 120-150℃, and the pressure is increased to 15-50 MPa, and the pressure holding time is 1-60 min, which ensures that the reaction container is in a supercritical temperature and supercritical pressure, and the supercritical fluid state is not broken in the reaction time.

[0034] Further, after the above steps, the passivation of Si3N4 dielectric layer traps and interface states, improves the quality of the dielectric layer, and the breakdown electric field is increased to 5.02-6.54 MV / cm, and the leakage current is reduced to 8*10 -7 ~2*10 -6 A1cm 2 .

[0035] In summary, the present application passivates Si3N4 dielectric layer traps and interface states at low temperature and high pressure, and the operation is simple and convenient, avoiding the problems caused by high temperature annealing process, thereby improving the quality of Si3N4 dielectric layer, increasing the breakdown electric field, and reducing the leakage current density.

[0036] The technical solutions of the present application are described in detail below with the help of the drawings and examples. DESCRIPTION OF DRAWINGS

[0037] Figure 1 The schematic diagram of the supercritical experimental equipment;

[0038] Figure 2The current density and electric field intensity before and after the supercritical fluid treatment are tested.

[0039] Wherein, 1. reaction kettle; 2. first Omega K type thermocouple; 3. second Omega K type thermocouple; 4. temperature controller; 5. SCR temperature controller; 6. heat preservation layer; 7. burst valve; 8. pressure gauge; 9. high pressure valve. DETAILED DESCRIPTION

[0040] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] In the present application, all the embodiments and preferred embodiments mentioned in the present application can be combined to form new technical solutions, unless otherwise specified.

[0042] In the present application, all the technical features and preferred features mentioned in the present application can be combined to form new technical solutions, unless otherwise specified.

[0043] In the present application, percentage (%) or part refers to the weight percentage or weight part of the composition, unless otherwise specified.

[0044] In the present application, the components or preferred components involved can be combined to form new technical solutions, unless otherwise specified.

[0045] In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand representation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "6~22" represents that all real numbers between "6~22" have been listed in the present application, and "6~22" is only a shorthand representation of these numerical combinations.

[0046] The lower limit and upper limit of the range disclosed in the present application can be one or more lower limits and one or more upper limits, respectively.

[0047] In the present application, the term "and / or" used in the present application refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0048] In the present application, unless otherwise specified, each reaction or operation step can be sequentially performed or performed according to the sequence. Preferably, the reaction method in the present application is sequentially performed.

[0049] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0050] Under different temperatures and pressures, the state of matter changes, resulting in different states such as liquid, gas, and solid. At specific temperatures and pressures, the liquid-gas interface disappears; this point is called the critical point. Supercritical fluids refer to fluids that exist in the temperature and pressure range above the critical point. Supercritical fluids possess unique physicochemical properties; their density is close to that of liquids, their viscosity is close to that of gases, and they have a high diffusion coefficient, low viscosity, and high dielectric constant.

[0051] This invention provides a high-quality silicon nitride dielectric passivation layer processing technology based on supercritical fluid and its application. Supercritical fluid can enter the surface and interior of the Si3N4 dielectric layer at 150°C to passivate traps in the interface surface, thus avoiding problems caused by high-temperature annealing processes. Because the supercritical fluid (SCF) state is a special phase with the coexistence of liquid and gas phases, SCCO2 and SCN2O possess the advantages of high solubility like gases and permeability like liquids. This allows the supercritical fluid to carry functional group molecules into the Si3N4 dielectric layer and interface to passivate traps and interface states within the dielectric layer at low temperatures, thereby improving the interface surface quality.

[0052] Please see Figure 1 The steady-state supercritical equipment includes a reactor 1. A first Omega K thermocouple 2 and a second Omega K thermocouple 3 are respectively installed on the side and bottom of the reactor 1. An insulation layer 6 is installed on the outside of the reactor 1, and a heating system is installed inside the insulation layer 6. The first Omega K thermocouple 2 and the second Omega K thermocouple 3 are respectively connected to an Eurotherm temperature controller 4 and an SCR temperature controller 5, and the temperature is displayed by the Eurotherm temperature controller 4. The SCR temperature controller 5 is connected to the heating system to control the heating insulation resistor to heat the reactor body of the reactor 1. A high-pressure pipe is connected to a burst valve 7, a pressure gauge 8 and a high-pressure valve 9 on the flange of the reactor 1.

[0053] This invention discloses a high-quality silicon nitride dielectric passivation layer processing technology based on supercritical fluid, comprising the following steps:

[0054] S1. Place the substrate sample with the Si3N4 dielectric layer onto the support inside the supercritical equipment, ensuring that the substrate sample is vertical.

[0055] S2. Fill the chamber of the supercritical equipment with deionized water, and then seal the supercritical equipment.

[0056] 0.5–2 mL of deionized water.

[0057] The volume ratio of 0.3% to 1.3% can make deionized water participate in the whole supercritical reaction process sufficiently, and there is no waste.

[0058] S3, control the pressure of 15-50MPa, and fill CO2 or N2O supercritical gas into the supercritical equipment;

[0059] The starting pressure of 10-12MPa is filled into the reaction kettle of the supercritical equipment, and then the equipment is subjected to corresponding pressure increasing process based on the pressure, so that the reaction can be carried out quickly and effectively.

[0060] S4, control the temperature increasing rate of 1-10℃ / min, increase the temperature of the supercritical equipment from 25℃ to 150℃, increase the pressure of the supercritical equipment to 15-50MPa, and then keep the pressure for 1-60min;

[0061] The deionized water is fully dissolved with CO2 through temperature increasing treatment, and the whole system can reach the supercritical state.

[0062] S5, keep the supercritical state treatment of step S4, reduce the pressure at 150℃, and keep the time of 1h under the supercritical treatment condition of 20-22MPa;

[0063] S6, after the reaction of step S5 is finished, the temperature of the reaction kettle is reduced to 30-60℃, the pressure increasing pump is stopped, the pressure is reduced to atmospheric pressure through the back pressure valve, and the sample is taken out.

[0064] The high-quality Si3N4 dielectric passivation layer can reduce the leakage level of the device, and lay a foundation for further preparation of high-performance semiconductor devices.

[0065] The breakdown field of the Si3N4 dielectric passivation layer after low-temperature treatment is 5.02-6.54MV / cm, and the leakage current density of the device is 8*10 -7 -2*10 -6 A1 2 .

[0066] The high-quality Si3N4 dielectric passivation layer treatment process based on supercritical fluid has a wide application in the fields of integrated circuits, micro-mechanical electronics, solar cells and display devices.

[0067] For example, in integrated circuits, due to its high dielectric constant, high density and good barrier to impurity ion diffusion, high-quality Si3N4 is used in MOSFET, HBT, HEMT and other semiconductor devices to reduce device leakage current and interface state density; in the field of micro-mechanical electronics, due to the excellent mechanical properties and small stress of the silicon nitride film, it is applied to micro-motor, micro-bridge deck, pressure sensor structure; in the field of solar cells, high-quality Si3N4 as an anti-reflection film not only reduces light reflection, but also plays a role in surface passivation and bulk passivation of the battery, thereby improving the conversion efficiency of the solar cell; TFT thin film transistor is the most common display device, and high-quality Si3N4 used as its gate insulating layer can greatly improve the reliability and stability of the device.

[0068] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0069] Embodiment 1

[0070] S1, place the substrate sample with Si3N4 dielectric layer on the support inside the supercritical device, ensure that the substrate sample is vertical;

[0071] S2, fill 0.5 mL of deionized water into the chamber of the supercritical device, and then seal the supercritical device;

[0072] S3, flush the reactor with a starting pressure of 10 MPa, control the pressure to be 15 MPa, and fill CO2 supercritical gas into the supercritical device;

[0073] S4, control the temperature rising rate to be 1℃ / min, raise the temperature of the supercritical device from 25℃ to 120℃, raise the pressure of the supercritical device to 15 MPa, and then keep the pressure for 1 min;

[0074] S5, maintain the supercritical state treatment of step S4, at 120℃, reduce the pressure and maintain the supercritical treatment condition at 20 MPa for 1 h;

[0075] S6, after the reaction of step S5 is completed, the temperature of the reactor is decreased to 30°C, the pressure pump is stopped, and the pressure is decreased to atmospheric pressure by a back pressure valve, and then the substrate sample is taken out.

[0076] After step S6 is completed, the breakdown field of the Si3N4 dielectric passivation layer on the low temperature treated substrate sample is 5.02 MV / cm, and the leakage current density of the device is 2 x 10 -6 A1cm 2 .

[0077] Example 2

[0078] S1, the substrate sample with a Si3N4 dielectric layer is placed on a support inside the supercritical device, ensuring that the substrate sample is vertical;

[0079] S2, 0.7 mL of deionized water is filled into the chamber of the supercritical device, and then the supercritical device is sealed;

[0080] S3, the initial pressure in the reactor is 11 MPa, the pressure is controlled at 25 MPa, and CO2 supercritical gas is filled into the supercritical device;

[0081] S4, the temperature is increased at a rate of 2°C / min, the temperature of the supercritical device is increased from 25°C to 125°C, the pressure of the supercritical device is increased to 20 MPa, and then the pressure is maintained for 20 min;

[0082] S5, the supercritical state treatment of step S4 is maintained, the pressure is decreased at 125°C, and the supercritical treatment is maintained at 20 MPa for 1.2 h;

[0083] S6, after the reaction of step S5 is completed, the temperature of the reactor is decreased to 40°C, the pressure pump is stopped, and the pressure is decreased to atmospheric pressure by a back pressure valve, and then the substrate sample is taken out.

[0084] After step S6 is completed, the breakdown field of the Si3N4 dielectric passivation layer on the low temperature treated substrate sample is 5.37 MV / cm, and the leakage current density of the device is 1.3 x 10 -6 A1cm 2 .

[0085] Example 3

[0086] S1, the substrate sample with a Si3N4 dielectric layer is placed on a support inside the supercritical device, ensuring that the substrate sample is vertical;

[0087] S2, 0.9 mL of deionized water is filled into the chamber of the supercritical device, and then the supercritical device is sealed;

[0088] S3, flush the reactor with an initial pressure of 11 MPa, control the pressure to be 35 MPa, and fill the supercritical device with N2O supercritical gas;

[0089] S4, control the temperature rising rate to be 4℃ / min, raise the temperature of the supercritical device from 25℃ to 130℃, raise the pressure of the supercritical device to 25 MPa, and then keep the pressure for 30 min;

[0090] S5, keep the supercritical state treatment of step S4, reduce the pressure at 130℃, and keep the time under the supercritical treatment condition of 21 MPa for 1.3 h;

[0091] S6, after the reaction of step S5 is completed, stop the pressure increasing pump when the temperature of the reactor is lowered to 45℃, and take out the substrate sample after the pressure is lowered to atmospheric pressure through the back pressure valve.

[0092] After step S6 is completed, the breakdown electric field of the Si3N4 dielectric passivation layer on the substrate sample after low temperature treatment is 5.72 MV / cm, and the leakage current density of the device is 9.4×10 -7 A1cm 2 .

[0093] Example 4

[0094] S1, place the substrate sample with Si3N4 dielectric layer on the support inside the supercritical device, and ensure that the substrate sample is vertical;

[0095] S2, fill 1.2 mL of deionized water into the chamber of the supercritical device, and then seal the supercritical device;

[0096] S3, flush the reactor with an initial pressure of 12 MPa, control the pressure to be 40 MPa, and fill the supercritical device with N2O supercritical gas;

[0097] S4, control the temperature rising rate to be 6℃ / min, raise the temperature of the supercritical device from 25℃ to 135℃, raise the pressure of the supercritical device to 35 MPa, and then keep the pressure for 40 min;

[0098] S5, keep the supercritical state treatment of step S4, reduce the pressure at 135℃, and keep the time under the supercritical treatment condition of 21 MPa for 1.5 h;

[0099] S6, after the reaction of step S5 is completed, stop the pressure increasing pump when the temperature of the reactor is lowered to 50℃, and take out the substrate sample after the pressure is lowered to atmospheric pressure through the back pressure valve.

[0100] After step S6 is completed, the breakdown electric field of the Si3N4 dielectric passivation layer on the substrate sample after low temperature treatment is 5.93 MV / cm, and the leakage current density of the device is 9×10 -7A1cm 2 .

[0101] Example 5

[0102] S1, the substrate sample with Si3N4 dielectric layer is placed on the support inside the supercritical device, ensuring that the substrate sample is vertical;

[0103] S2, 1.7 mL of deionized water is filled into the chamber of the supercritical device, and then the supercritical device is sealed;

[0104] S3, the initial pressure of 12 MPa is injected into the reaction kettle, the pressure is controlled to be 45 MPa, and CO2 supercritical gas is filled into the supercritical device;

[0105] S4, the temperature rising rate is controlled to be 8℃ / min, the temperature of the supercritical device is raised from 25℃ to 140℃, the pressure of the supercritical device is raised to 45 MPa, and then the pressure is kept for 50 min;

[0106] S5, the supercritical state treatment of step S4 is maintained, the pressure treatment is carried out at 140℃, and the supercritical treatment is carried out at 22 MPa for 1.8 h;

[0107] S6, after the reaction of step S5 is completed, the temperature of the reaction kettle is reduced to 55℃, the pressure increasing pump is stopped, and the pressure is reduced to atmospheric pressure through the back pressure valve, and then the substrate sample is taken out.

[0108] After step S6 is completed, the breakdown field of the Si3N4 dielectric passivation layer on the substrate sample after low temperature treatment is 6.25 MV / cm, and the leakage current density of the device is 8.7×10 -7 A1cm 2 .

[0109] Example 6

[0110] S1, the substrate sample with Si3N4 dielectric layer is placed on the support inside the supercritical device, ensuring that the substrate sample is vertical;

[0111] S2, 2 mL of deionized water is filled into the chamber of the supercritical device, and then the supercritical device is sealed;

[0112] S3, the initial pressure of 12 MPa is injected into the reaction kettle, the pressure is controlled to be 50 MPa, and N2O supercritical gas is filled into the supercritical device;

[0113] S4, the temperature rising rate is controlled to be 10℃ / min, the temperature of the supercritical device is raised from 25℃ to 150℃, the pressure of the supercritical device is raised to 50 MPa, and then the pressure is kept for 60 min;

[0114] S5, maintaining the supercritical state processing of step S4, reducing pressure processing at 150 DEG C, and maintaining the supercritical processing condition at 22 MPa for 2 hours;

[0115] S6, after the reaction of step S5 is completed, the temperature of the reactor is reduced to 60 DEG C, the booster pump is stopped, and the pressure is reduced to atmospheric pressure through a back pressure valve, and then the substrate sample is taken out.

[0116] After step S6 is completed, the breakdown field of the Si3N4 dielectric passivation layer on the substrate sample after low temperature processing is 6.54 MV / cm, and the leakage current density of the device is 8*10 -7 A1cm 2 .

[0117] As seen from the above examples, after the Si3N4 dielectric passivation layer is processed by the supercritical fluid processing process, the breakdown field is greatly improved, and the leakage current of the device is reduced.

[0118] Referring to Figure 2 , the current density and electric field strength test results before and after supercritical fluid processing are shown in the figure, and it can be seen that the breakdown field strength of the Si3N4 dielectric passivation layer is greatly improved after supercritical fluid processing, and the breakdown field strength is improved from 4.93 MV / cm to 6.54 MV / cm.

[0119] In summary, the high-quality Si3N4 dielectric passivation layer processing process based on supercritical fluid of the present application passivates the traps and interface states in the dielectric layer at low temperature, and is simple and convenient to operate, avoids the problems caused by the high-temperature annealing process, thereby improving the quality of the Si3N4 dielectric passivation layer, greatly improving the breakdown field strength, and reducing the leakage current.

[0120] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A supercritical fluid based high quality silicon nitride dielectric passivation layer processing process, characterized in that, The method comprises the following steps: S1, vertically placing a substrate sample with a Si3N4 medium passivation layer into a reaction container; S2, filling deionized water into the reaction container and sealing the reaction container; S3, controlling the pressure, and filling CO2 or N2O supercritical gas into the reaction container sealed in step S2; S4, performing temperature and pressure increasing treatment on the reaction container filled with CO2 or N2O supercritical gas in step S3, and then keeping the pressure, so that the inside of the reaction container is in a supercritical state; S5, keeping the supercritical state treatment in step S4, and performing pressure decreasing treatment on the reaction container, and keeping the supercritical treatment condition at 20-22 MPa; S6. After the reaction in step S5 is completed, the reaction vessel is cooled down. Once the pressure is reduced to atmospheric pressure, it is removed. The breakdown electric field of the silicon nitride dielectric passivation layer is 5.02~6.54 MV / cm, and the leakage current density of silicon nitride is 8×10⁻⁶. -7 ~2×10 -6 A / cm 2 .

2. The supercritical fluid based high quality silicon nitride dielectric passivation layer treatment process of claim 1, wherein, In step S2, 0.5-2 mL of deionized water is filled into the reaction container, and then the reaction container is sealed.

3. The supercritical fluid based high quality silicon nitride dielectric passivation layer treatment process of claim 1, wherein, In step S3, the initial pressure of the reaction container is 10-12 MPa, and then the pressure of the reaction container is controlled to be 15-50 MPa, and CO2 or N2O is filled.

4. The supercritical fluid based high quality silicon nitride dielectric passivation layer treatment process of claim 1, wherein, In step S4, the temperature of the reaction container is increased from 25℃ to 120-150℃, the pressure is increased to 15-50 MPa, and the pressure keeping time is 1-60 min.

5. The supercritical fluid based high quality silicon nitride dielectric passivation layer processing process of claim 4, wherein, The temperature increasing rate of the reaction container is 1-10℃ / min.

6. The supercritical fluid based high quality silicon nitride dielectric passivation layer processing process of claim 1, wherein, In step S5, the temperature for the pressure decreasing treatment on the reaction container is 120-150℃.

7. The supercritical fluid based high quality silicon nitride dielectric passivation layer processing process of claim 1, wherein, In step S5, the keeping time under the supercritical treatment condition is 1-2 h.

8. The supercritical fluid based high quality silicon nitride dielectric passivation layer processing process of claim 1, wherein, In step S6, the temperature for the temperature decreasing treatment is 30-60℃.

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