DOUBLE-LAYER NUCLEAR RADIATION SENSITIVE FIELD-EFFECT TRANSISTOR (NURFET) DOSIMETERS

Abstract

The invention relates to bilayer nuclear radiation-sensitive field-effect transistor (NürFET) dosimeters that enable the detection, measurement, and monitoring of ionizing radiation. Specifically, the invention concerns bilayer nuclear radiation-sensitive field-effect transistor (NürFET) dosimeters designed using chip processing and thin-film growth technologies on n-type silicon substrates. These dosimeters are created by growing a silicon dioxide layer through oxidation, followed by lithography and diffusion processes to form n+ and p-type regions. An erbium oxide / scandinium oxide gate dielectric layer is added to the gate silicon dioxide to trap ionizing radiation-sensitive charges, and the sensitivity is enhanced with high-density samarium and aluminum coatings.

Description

1 TARIFF DOUBLE-LAYER NUCLEAR RADIATION SENSITIVE FIELD-EFFECT TRANSISTOR (NURFET) DOSIMETERS TECHNICAL AREA 5 The invention enables the detection, measurement, and monitoring of ionizing radiation. with layered nuclear radiation sensitive field effect transistor (NürFET) dosimeters It is related. 10 The invention specifically concerns chip processing and thin-film growth on n-type silicon substrates. Designed using advanced technologies, the silicon dioxide layer is grown through oxidation. Then, n+ and p-type regions are formed through lithography and diffusion processes, and ionized. Erbium is placed on silicon dioxide for trapping radiation-sensitive charges. High-density samarium 15 is produced by adding an oxide / scandinium oxide gate dielectric layer. and aluminum coatings for increased sensitivity to nuclear radiation, double-layered structure. This relates to sensitive field-effect transistor (NürFET) dosimeters. STATE OF THE ART 20 NurFETs hold a significant position in the field of radiation dosimetry and semiconductor sensors. These disciplines have resulted in the detection, measurement, and... of ionizing radiation. This includes the development of various devices for monitoring. Ionizing radiation, when it has sufficient energy, interacts with matter and emits 25... a radioactive substance that has the capacity to form ions by removing electrons from atoms It is a type of radiation. This process causes a change in the electrical charges of atoms and therefore It can lead to the breakdown of chemical bonds. 30 2 The main types of ionizing radiation are listed below: - Alpha particles (α): They are heavy in terms of weight and slow in terms of speed; low They have penetrating power and can be stopped by simple materials like paper. - Beta particles (β): Lighter and faster than alpha particles; usually several 5 They can be stopped with plastic or glass just millimeters thick. - Gamma rays (γ) and X-rays: These types of radiation have high penetration power. It can only be stopped with lead or thick concrete slabs. 10 - Neutrons: Because they are uncharged, they have high penetration power and can penetrate water. or they can be stopped by materials like concrete. Ionizing radiation is used in medical imaging, cancer therapy, nuclear energy production, and various other applications. Widely used in many fields, including industrial applications 15 It is used. However, due to its harmful effects on living tissues, this Monitoring and controlling radiation requires great care. Radiation dosimetry measures the results of the interaction of ionizing radiation with matter. It is a branch of science that measures the energy released in doses. The main goal in this discipline is to measure the energy released by individuals in 20 or measuring the amount of ionizing radiation to which electronic devices are exposed. The dosimeters used are divided into two main categories. The first of these is based on the environment. These are active dosimeters that have the capacity to measure radiation dose instantly; the other is... The total ionizing dose (TID) to which one is exposed can be measured at specific intervals or They are passive dosimeters that read through specific transducers. 25 In this context, NurFETs are classified as passive radiation dosimeters. Passive Dosimeters measure the dose of radiation received when exposed to it, using a measuring device. They have the ability to store information until it is read; therefore, they do not provide real-time dosage information. NürFETs are also based on this principle; semiconductor-based Metal-Oxide-Semiconductor 30 3 Having a field-effect transistor (MOSFET) structure, it reacts when exposed to radiation. Charge accumulation occurs in the gate oxide / dielectric layer. This charge accumulation causes the device to reach its threshold. It changes the voltage, and the total dose is calculated as a result of this change. However, if continuous readings can be achieved using suitable electronic circuits, NürFETs can have 5 It can also function as a semi-active monitoring system. In this case, the sensor section is passive. The reading circuit remains active. NürFET technology, also referred to as RadFET in the literature, is particularly suitable for applications with 10 mGy and higher frequencies. radioactive radiation sensitive sensor 10 used at high radiation levels above These sensors have a wide range of applications. They are used in nuclear power plants, space, and more. research and military applications that involve high radiation exposure It is used in various environments. In this context, in nuclear reactors, spacecraft safety measures and quality control in systems and various industrial applications They are of critical importance in this respect. Furthermore, radiation in radiotherapy applications is 15 There are also potential applications in the healthcare field, such as monitoring dosage. In conclusion, NürFETs are used in specialized fields such as nuclear and space technologies, a significant player capable of providing safe and accurate measurements in both industrial and healthcare sectors. It is a technological tool. 20 NürFETs are a semiconductor silicon-based p-channel MOSFET technology that reduces radiation. It works by taking advantage of its sensitivity. Its working principle is as follows: • Radiation Effect: Ionizing radiation (e.g., gamma rays, X-rays, or high-energy particles), electron-hole pairs in the oxide / dielectric layer of the MOSFET 25 It forms. Only one of these pairs should accumulate in the structure. • Charge Accumulation: Holes released in the oxide / dielectric layer become trapped. This results in a permanent accumulation of charge, while the electrons quickly move away. 30 4 • Threshold Voltage Change: This charge accumulation changes the threshold voltage (Vth) of the MOSFET. As the radiation dose increases, the shift in Vth also increases. • Dose Measurement: This change in threshold voltage is measured using electronic circuits to determine exposure. The total ionization dose received is calculated. 5 With current technology, the sensitivity of NürFET dosimeters is seriously compromised at low dose levels. This shows limitations. This situation occurs in the gate oxide / dielectric layer. This is due to the accumulation of radiation-induced charge. At high doses. Although it can successfully measure ionizing radiation, it is only effective at low dose levels. their insufficient sensitivity, radioactive material detection, and low dose. This makes it difficult to accurately determine radiation exposure levels. Although the minimum measurement threshold stated in the literature is 10 mGy, 100 Limitations in measuring doses below mGy include the physical properties of the gate oxide / dielectric layer. This is due to its properties. In currently commercial NürFETs, this layer is usually silicon. It is constructed with dioxide (SiO₂). However, SiO₂'s sensitivity to low doses... Its inadequacy leads to increasing the detection threshold and enabling more precise dose measurements. It prevents. 20 In recent years, a better sensitivity to higher dose levels has been achieved. For this purpose, in addition to traditional SiO₂, Erbium, which has a high dielectric constant, was chosen. The use of dielectric materials such as oxide (Er₂O₃) has been suggested. The benefits provided by Er₂O₃ High dielectric constant, effective atomic number, and radiation resistance are specific advantages. However, this material has some significant technical disadvantages: 25 1. Initial Oxide Loads: In the Er₂O₃ layer, high initial oxide loads are formed during production. Oxide charges cause the device to deviate even in a radiation-free environment, and This negatively affects dose measurement accuracy. 30 2. Unstable Load Traps: The unstable nature of load traps in Er₂O₃ means that the loads change over time. This leads to a rearrangement, negatively affecting dose calibration. 3. Electrophysical Incompatibility: Between Er₂O₃ and the silicon used as a substrate. Electrophysical incompatibility increases interface states and reduces the overall accuracy of the device by 5. It reduces. Identifying suitable dielectric materials requires intensive research and development activities. This results in a possible outcome. In this context, an effective passage dielectric results in low radiation. Even at high doses, it accumulates only one type of carrier (electron or hole) in its structure. 10 It must have the capacity. In this patent application, the gate dielectric region is double. Layered structures such as Er₂O₃ / SiO₂ and Sc₂O₃ / SiO₂ are proposed. Aluminum is traditionally used as the contact metal for the bushing, and this material... Its primary function is to detect ohmic electrical signals from the drain, stack, and source regions. The aim is to obtain. Also in this patent application, high-density metals (for example, Fence layers formed with samarium, especially with aluminum, as a gateway electrode. The addition of secondary radiation from high-energy X-ray radiation above 1 MeV results in a double radiation effect. By increasing their frequency, it offers the potential to improve the sensitivity of the devices. 20 Another limitation in current technology for semiconductor-based sensors is: These are effects related to temperature changes. NürFET dosimeters are affected by environmental conditions, It can be particularly severely affected by temperature changes. Temperature changes can damage the device. This causes shifts in electrical parameters, negatively affecting the accuracy of measurements. This can affect it. This situation requires additional adjustments or 25 in order to reduce temperature dependence. Calibrations are required. In reading circuits, corresponding to a zero temperature coefficient. Measuring incoming current values ​​is one of the efforts and methods to increase sensitivity. This is one of them. With this method, the direct effect of temperature fluctuations is minimized. Work is underway. 30 6 In current technology, the size and structural configurations of NurFET dosimeters are generally It includes certain limitations, which makes its use restricted to some specific applications. This makes it difficult. For example, in very small areas or micro-sized dosimeters. In applications requiring such devices, the use of NürFET devices remains limited. Furthermore, incoming Performance changes by approximately 20 percent depending on the direction of radiation. 5 This can demonstrate compliance with the requirements of the applications in question. This poses a significant challenge. In the patent numbered CA 02701535, which is included in the current technology, the inventor is URYUPIN OLEG, Increasing sensitivity by using the amplification principles of classic MOSFET inverters. They have developed a new circuit design for this purpose. The patent numbered US4976266A, which is included in the current technology, describes a new approach to classic RadFETs. with packaging design and integrated into the body, in vivo dosimeters This indicates that research has been conducted on its use. However, for these structures, 15 Despite being patented, there is no indication that these systems have been commercialized. No information was available. In the current technique, by UNIV COLLEGE CORK NATIONAL UNIV OF IRELAND CORK The patent numbered US2024184000A1 describes channel 20 MOSFET transistors. New RadFETs are created by modifying their widths and adding impurity additives during implantation. It is stated that the designs have been improved. The images provided in this patent show responsive designs. Classical SiO₂ is suggested as the region. In the current technique, the classic 25 is used in Turkish patent application number 2019 / 10263. Unlike NürFETs, coating a boron layer onto SiO₂ results in neutron emission. its radioactivity interacts with boron, producing secondary gamma radiation. The aim was to increase the sensitivity of the devices. As a result, the boron layer, To enable neutrons to interact and scatter or generate secondary radiation. It is used for this purpose. 30 7 In conclusion, in order to solve the aforementioned problems that exist in the current technology, an economical, safe and convenient double-layered nuclear radiation sensitive area The need for effective transistor (NürFET) dosimeters and the current solutions are 5 The deficiency has made it necessary to make improvements in the relevant technical field. THE PURPOSE OF THE INVENTION The present invention aims to eliminate the aforementioned disadvantages and contribute to the relevant technical field. Developed to offer new advantages, this double-layered, nuclear radiation-sensitive structure It is related to field-effect transistor (NürFET) dosimeters. The main objective of the invention is to reduce the initial oxide charges. The developed dual In the multilayered dielectric structure, an ultra-thin 5-10 nm thick 15-layer substrate is used. SiO₂ reduces the mismatch between the second dielectric layer and the substrate, resulting in lower voltage. It minimizes the initial interface charge and the total initial oxide / dielectric charge. This process stabilizes the device's core characteristics, thereby improving its performance. This allows for an increase in the reliability of the device's measurement results. is being increased. 20 Another advantage of the invention is the control of charge traps. Double-layer gate dielectric. In its structure, a material with a high dielectric constant is used in the top layer, while the bottom layer... The layer acts as a buffer, stabilizing the charge traps. This design reduces the dose. By preventing calibration deviation over time, the device will maintain its calibration for 25 years during long-term use. This increases its accuracy. The aforementioned upper layer contains Erbium Oxide (Er₂O₃) and Scandium oxide (Sc₂O₃) materials have been developed as a result of intensive R&D efforts. This has been discovered and has increased the effectiveness of this system. Another advantage of the invention is the increased sensitivity. Within the double-layer gate electrode structure, 30 8 Using samarium, which has a higher density compared to traditional aluminum, 1 Secondary radiation pair formation in X-ray radiation with energies of MeV and above. This triggers the creation of secondary radiation pairs and the passage which is the sensitive region. Interaction with the dielectric layer leads to an increase in the charges accumulated in the oxide / dielectric structure, and Therefore, it contributes to a significant improvement in the sensitivity of the device. 5 Another advantage of the invention is the increased sensitivity to low doses. Double-layer gate metal and... Optimized design of the double-layer gate dielectric structure allows for better performance at lower doses. It provides precise charge accumulation. Thus, sensitivity is increased at doses of 1 mGy and above. Measurement is being increased and used in critical applications such as monitoring low-dose radiation environments. High sensitivity is achieved. This feature enables the developed technology to be used in medical and industrial applications. This ensures that it has a wide range of applications in various fields. Another advantage of the invention is the increased sensitivity to low doses. The developed double-layered system... The NürFET design provides high sensitivity at doses of 1 mGy and above. This feature is available in 15 especially sensitive environments such as medical imaging and monitoring of low-dose radiation. This offers a critical advantage in measurements. Currently, NürFET-like sensors The current measurable limit value is 10 mGy, and the stable measurable limit value is 100 mGy. It is above these limitations; therefore, the developed design has the potential to overcome them. 20 Another advantage of the invention is the reduction of initial oxide charges. The double-layered structure, single The layer significantly reduces initial oxide charges compared to its high-k dielectric counterparts. It has the capacity to reduce radiation. This means the device can reduce radiation even in a radiation-free environment. by preventing it, a more stable and reliable fundamental characteristic is obtained. This contributes to the device's performance and measurement reliability. It is being improved and its stable operation is being ensured. Another advantage of the invention is the stabilization of the charge traps. The lower dielectric layer By acting as a buffer, it stabilizes interface-borne charge traps. This feature ensures that calibration deviations are reduced to 30% even during long-term use. 9 By preventing this, it increases the accuracy of the device. Thus, the developed design is continuous and It has the capacity to provide reliable measurement results. The structural and characteristic features and all the advantages of the invention are given in the figures below. Thanks to the detailed explanation written with references to these figures, 5 is clearer. This will be understood, and therefore the evaluation should also take these forms and detailed explanations into consideration. It needs to be done by taking precautions. FIGURES THAT WILL HELP UNDERSTAND THE INVENTION FIGURE 1; Subject of the invention: Double-layer nuclear radiation sensitive field-effect transistor 10 This is a diagram showing the (NürFET) dosimeters. REFERENCE NUMBERS 10. N-Type Silicone Substrate 20. Field Oxide Layer (SiO2) 15 30. N+ Type Stack Area 41. P-Type Welding Area 42. P-Type Drainage Area 50. Transition Dielectric Layer (SiO2) 60. Erbium Oxide / Scandinium Oxide Dielectric Layer 20 70. Samarium Gate Metal 80. Aluminum Gate Metal DETAILED DESCRIPTION OF THE INVENTION This detailed explanation describes a double-layered nuclear radiation-sensitive field effect. The preferred configurations for transistor (NürFET) dosimeters are simply due to the greater complexity of the subject. 5 for the purpose of being well understood and without creating any limiting effects It is explained. Figure 1 shows the subject of the invention: a double-layered nuclear radiation-sensitive field-effect electrode. The images show transistor (NürFET) dosimeters. Our invention is architecturally n-type. Using chip processing and thin film growth technologies on silicon substrates (10) 10 is being designed. For the target structure, the entire substrate is first prepared using the wet oxidation method. Silicon dioxide (20), which has an area oxide layer on it, is grown. Area oxide After the layer is enlarged, phosphorus doping will be carried out using lithography processes. By opening a channel, an n+ type bulk (30) region is created in diffusion ovens. The following In the stage, the source (41) and drain (42) through which the current will flow during the electrical measurements of the device 15 The area oxide layer is removed by lithography to create the regions, and diffusion is used. p-type regions are obtained by boron doping in furnaces or by implantation method. is being done. The formation of ionizing radiation-sensitive charges and the trapping of uniform charges in the region is 20. A third lithography process was applied to determine the passage dielectric. The area corresponding to the layer (50) is removed. At this stage, dry transition silicon dioxide approximately five to ten nanometers thick was produced by oxidation method. The dielectric layer (50) is grown. Silicon dioxide is placed at the transition gate interface. Its existence has two important functions: Firstly, silicon 25, which is the substrate (10) material. By creating a structure with low interface defects, the final device becomes more stable. to enable it to function and create low stress with a second layer that can be added on top; Secondly, due to its structure, it produces monotypic hole carriers when it interacts with radiation. 11 The goal is to trap it. On top of this structure, a layer of erbium oxide between one hundred and four hundred nanometers thick is applied. or scandinium oxide dielectric coating (60) is performed. These two The material's characteristic is that conventional silicon dioxide emits radiation per unit amount. By trapping higher numbers of uniform hole loads according to the layer, the final product is It contributes to a critically increased sensitivity of NürFET dosimeters. 5 Furthermore, the uniform charge deposition capacity of the Er₂O₃ and Sc₂O₃ dielectrics used is such that... This ensures that the materials are site-specific. After dielectric coating, the samarium gate metal (70) coating process is thermal. This is done by the evaporation method. In this stage, preferably a density of 7.0-10 is used. The use of metals with a yield above g / cm³ is important, and for this purpose, samarium is used. The metal was chosen. The purpose of the high-density metal is to detect X-rays with energies of MeV and above. by interacting with radiation, such as electron radiation, which has a high cross-section. Unit radiation in dielectric layers, leading to the production of secondary radiation. By enabling the formation of a greater number of loads and traps in that quantity, the sensitivity of the device is increased by 15. The aim is to increase it. However, the fact that this material is conductive is important in terms of the stability of the device. It is also an important element. In the final stages, aluminum gate metal (80) regions are formed by lithography. The area where it will be placed is being opened. At this stage, 20 for triggering on the passage surface. It will be used and exhibit ohmic properties with silicon, transmitting signals during electrical measurements. aluminum coating to prevent defects, produced by thermal evaporation method is being carried out. Our invention is a double-layer nuclear radiation-sensitive field-effect transistor (NürFET) 25 They have dosimeters; - n-type silicon substrate (10) which forms the body of the device and is made of n-type silicon, - By providing insulation during production and subsequent measurement, it prevents unwanted inhibits channel formation and parasitic interactions between adjacent structures. 12 reducing area oxide layer (20)(SiO₂) - Formed by phosphorus doping, it controls the channel during the flow of electrical current. by balancing the operating voltage of the device, it prevents unwanted current paths. n+ type bulk region preventing (30), - After the passage is triggered, by providing hole carriers, current flow 5 the source that starts (41) and the drain that collects this current and transmits it to the rest of the circuit. (42) regions, - Silicon Oxide, Substrate (10) material grown by dry oxidation method. By creating a structure with silicon that has low interface defects, the device is more by ensuring stable operation and reducing stress to 10 with the second layer to be built on top. minimizes its formation when it interacts with radiation due to its natural structure. uniform load accumulation at the interface by capturing uniform hole carriers. by providing a transition dielectric layer (50) that contributes to radiation sensitivity, - Charge carriers (especially uniform holes) formed by radiation effects. 15 Total ionization by determining the threshold voltage change through capacitive interaction. by maintaining the electrical stability of the device, which helps to determine the dose. provides reliability in long-term dose measurements and is a traditional silicon dioxide alternative. a higher number of uniform holes per unit radiation dose relative to the layer Erbium oxide / 20 improves the sensitivity of devices by trapping their payloads. Scandinium oxide dielectric layer (60), - By interacting with X-ray radiation of MeV and above energy, electrons which leads to the production of secondary radiation with high cross-sections, such as radiation, and Gate dielectric layers trap more charge per unit radiation. Samarium gate metal (70), which increases the sensitivity of the device by enabling its formation, 25 - a p-type channel that functions as a conductive layer when gate voltage is applied. controlling the movement of charges along its length, exhibiting ohmic properties. By applying an electrical field, an electrical field is created on the channel. aluminum gate that regulates current flow by changing carrier density It contains metal (80). 30 13 The scope of protection in this application is defined in the claims section and is explicitly stated above. The examples given cannot be limited to those described; a person skilled in the technique can make a difference in the invention. the innovation presented can be achieved by using similar structures and / or 5 This structure can also be applied to other similar fields using the same technique. It is clear. Therefore, such structures foster innovation and, in particular, the state of the technology. It is also obvious that it will lack the criterion of being surpassed.

Claims

14 REQUESTS 1- Invention of a double-layer nuclear radiation-sensitive field-effect transistor (NürFET) It relates to dosimeters, and its characteristic is; - n-type silicon substrate (10) which forms the body of the device and is made of n-type silicon, - By providing insulation during production and subsequent measurement, it prevents unwanted 5 parasitic interactions between adjacent structures that prevent channel formation reducing area oxide layer (20)(SiO₂) - Formed by phosphorus doping, it controls the channel during the flow of electrical current. by balancing the operating voltage of the device, it prevents unwanted current paths. n+ type bulk region preventing (30), 10 - providing hole carriers after the passage is triggered, thus facilitating current flow the source that starts (41) and the drain that collects this current and transmits it to the rest of the circuit. (42) regions, - It is Silicon Oxide grown by dry oxidation method, Substrate (10) By creating a structure with low interfacial defects using silicone as the material, 15 by making the device work more stably and by adding a second layer on top of it. Minimizing stress generation, due to its natural composition, it interacts with radiation. By capturing uniform hole carriers when it enters, it provides uniform load at the interface. Transition dielectrics contribute to radiation sensitivity by enabling their accumulation. plate-like (50), 20 - Charge carriers (especially uniform holes) formed by radiation effects. By capturing them, it enables the measurement of electrical changes for dosimetry purposes. Total ionization by determining the threshold voltage change through capacitive interaction. by maintaining the electrical stability of the device, which helps to determine the dose. providing reliability in long-term dose measurements and unlike traditional silicon dioxide 25 a higher number of uniform holes per unit radiation dose relative to the layer Erbium oxide improves the sensitivity of devices because it traps their payloads. Scandinium oxide dielectric layer (60), It is characterized by its inclusion. 2- Transistor (NürFET) dosimeters conforming to Claim 1, with the characteristic of having energies of MeV and above. By interacting with X-ray radiation, it produces highly potent forms of electron radiation. This leads to the production of cross-sectional secondary radiation and unity in the dielectric layers. By providing a higher charge and trap formation per radiation, the sensitivity of the device is increased by 5. It is characterized by the presence of samarium gate metal (70) which increases it. 3- Transistor (NürFET) dosimeters conforming to Claim 1, characterized by their ability to detect radiation effects. Measuring electrical changes for dosimetry purposes by capturing hole carriers. providing, maintaining the electrical stability of the device, traditional single-layer silicon 10 Double-gate dielectric that improves the sensitivity of devices according to the dioxide layer. It is characterized by containing Er₂O₃(60) / SiO₂(50) and Sc₂O₃ / SiO₂. 4- Transistor (NürFET) dosimeters conforming to Claim 1, with the characteristic of having a gate voltage of 15 When applied, it functions as a conductive layer, transferring charges along the p-type channel. an electrical field applied to it that controls its movement and exhibits ohmic properties. By creating an electrical field on the channel, it increases the carrier density. by containing aluminum gate metal (80) which regulates the flow of current by changing it It is characterized. 20

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