CN103872106B - Flouride-resistani acid phesphatase bipolar device and the preparation method of this device - Google Patents

Abstract

The anti-radiation bipolar device and the preparation method of the device relate to the anti-radiation technology of the bipolar device. It aims to solve the problem of poor radiation resistance of existing bipolar devices. In the present invention, a high doping concentration region with the emission region as the center is arranged on the surface of the base region of the bipolar device. The preparation method of the radiation-resistant bipolar device is as follows: after the diffusion or ion implantation of the base area is completed, and before the diffusion or ion implantation of the emitter area, the radiation-resistant strengthening method is carried out. Prepare the doping mask on the surface of the base region, implant the same impurity ions as in the body of the base region into the surface of the base region based on the mask, the implantation concentration is 10 to 10000 times that of the body region, and finally perform annealing treatment. In the invention, by changing the surface structure and doping concentration of the base area, the failure threshold of the device is increased by 1.4 to 3.7 times. The invention is applicable to NPN devices, PNP devices, digital bipolar circuits, analog bipolar circuits and digital/analog circuits.

Description

Radiation-resistant bipolar device and its preparation method

technical field

The invention relates to anti-radiation technology of bipolar devices.

Background technique

During the flight in orbit, the spacecraft interacts with various charged particles (electrons and protons) in space. These electrons and protons have a strong impact on the performance of electronic devices used in spacecraft, causing ionizing radiation effects, displacement radiation effects, and single event effects. These radiation effects will lead to abnormalities or failures of electronic devices, and even eventually lead to catastrophic accidents in spacecraft. The research results at home and abroad show that different forms of failures will occur on the spacecraft in orbit, which shortens the working life and causes great losses. The results of fault analysis show that the radiation damage effect of space charged particles on electronic devices on spacecraft is an important cause of faults and even accidents. Today, with the development of aerospace science and technology, higher requirements are put forward for the radiation resistance index of electronic devices used in spacecraft. With the improvement of these requirements, the development of anti-radiation principles and technologies of electronic components becomes more important.

Bipolar transistors have good current drive capability, linearity, low noise, and excellent matching characteristics. They play an important role in analog or hybrid integrated circuits and BiCMOS circuits, and these circuits and bipolar transistors are often used in space environments. Therefore, it has very important engineering practical significance for improving the anti-radiation ability of bipolar devices, optimizing the material selection and design of spacecraft, and improving the reliability of spacecraft in orbit.

For the currently commonly used silicon devices, most bipolar devices use _SiO2 oxide layer to protect the device surface. This forms the SiO ₂ /Si interface. Total dose irradiation (ionization damage) will generate trapped positive charges in the oxide layer and interface states at the SiO ₂ /Si interface. Both positive charge trapping and interface state increase the surface recombination rate of carriers, leading to a decrease in minority carrier lifetime, a decrease in current gain and an increase in junction leakage in bipolar devices.

After bipolar devices (especially NPN bipolar transistors) are damaged by radiation, positive charge captured by the oxide will cause the depletion layer on the surface of the emitter junction (N ⁺ P junction) and the base region to expand to the base region (P-type region) , increasing the recombination current in the depletion layer, leading to an increase in the excess base current ΔI _B of the bipolar device (base current minus the initial base current after irradiation), which affects the reliability and life of the bipolar device. The schematic diagram of the extended structure of the depletion layer of the bipolar transistor is shown in Figure 1.

Therefore, under the premise of not affecting the electrical performance index of bipolar devices, greatly reducing the impact of positive charges captured by oxides on device performance, and effectively improving the radiation resistance of bipolar devices will have a significant impact on the radiation resistance of the entire integrated circuit. Photo reinforcement is of great significance.

Contents of the invention

The object of the present invention is to solve the problem of poor radiation resistance of existing bipolar devices, and propose a radiation-resistant bipolar device based on optimizing the surface structure and concentration of the device base region and a preparation method of the device.

In the radiation-resistant bipolar device of the present invention, a high-doping concentration region centered on the emitter region is provided on the surface of the base region, and the doping concentration of the high-doping concentration region is 10-10% of the doping concentration of the body region. 10000 times.

The high doping concentration region is a multi-ring type high doping concentration region or a rectangular grid type high doping concentration region.

The depth of the multi-ring high doping concentration region is 1/20~1/5 of the depth of the emission region, the width of the ring is 0.01~10μm, the minimum distance between the inner ring boundary and the emission region boundary is 0.01~10μm, two adjacent The pitch of the rings is 0.1 to 10 μm, and the number of rings is 1 to 10.

The depth of the highly doped concentration area in the rectangular grid format is 1/20 to 1/5 of the depth of the emission area, the length and width of the rectangular grid are both 0.01 to 10 μm, and the minimum distance between the rectangular grid and the boundary of the emission area is 0.01 to 10 μm , the distance between two adjacent rectangular grids is 0.1-10 μm, and the number of rows and columns of the grids are both 2-100.

The preparation method of the radiation-resistant bipolar device of the present invention is: after the diffusion or ion implantation of the base area is completed, and before the diffusion or ion implantation of the emitter area, the radiation-resistant strengthening method is carried out, and the radiation-resistant strengthening method This is achieved through the following steps:

Step 1. On the basis of the mask of the base region, prepare a doped mask on the surface of the base region;

Step 2, implanting the same impurity ions as those in the body of the base region into the surface of the base region based on the mask, the implantation depth is 1/20-1/5 of the depth of the emission region, and the implantation concentration is 10-10000 times the concentration of the body region;

Step 3: After the implantation is completed, perform annealing treatment, the annealing temperature is the same as the annealing temperature during the diffusion or implantation of the base body, and the annealing time is the same as the annealing time during the diffusion or implantation of the base body.

The doping mask on the surface of the base region described in the first step is a multi-ring mask or a rectangular grid mask.

The width of the ring of the multi-ring mask is 0.01-10 μm, the minimum distance between the boundary of the inner ring and the boundary of the emission area is 0.01-10 μm, the distance between two adjacent rings is 0.1-10 μm, and the number of rings is 1 to 10.

The length and width of the rectangular grid of the rectangular grid mask are both 0.01-10 μm, the minimum distance between the rectangular grid and the boundary of the emission area is 0.01-10 μm, and the distance between two adjacent rectangular grids is 0.1-10 μm. 10 μm, the number of rows and columns of the grid are both 2 to 100.

Without affecting the electrical performance parameters of the device, the present invention can greatly reduce the recombination leakage current of the bipolar device, especially reduce the excess base region The electrode current ΔI _B reduces the damage degree of the current gain of the bipolar transistor, and achieves the purpose of improving the anti-irradiation ability of the bipolar device. Compared with the traditional base structure, the failure threshold of bipolar transistors with highly doped regions is at least 1.4 to 3.7 times higher.

Description of drawings

Figure 1 is a schematic diagram of the structure of the depletion layer of a common bipolar device after irradiation;

2 is a schematic structural diagram of the multi-ring high doping concentration region of the radiation-resistant bipolar device described in Embodiment 2;

3 is a schematic structural view of a rectangular grid-like high-doping concentration region of the radiation-resistant bipolar device described in Embodiment 4;

FIG. 4 is a schematic structural view of the depletion layer of the radiation-resistant bipolar device in Embodiments 2 and 4 after irradiation;

Fig. 5 is the relationship between the current gain of the bipolar transistor and the absorbed dose in Embodiments 2 and 4;

Fig. 6 is an experimental effect diagram in the eleventh to thirteenth embodiments.

detailed description

Specific implementation mode 1: This implementation mode is described with reference to FIG. 4 and FIG. 5 . The radiation-resistant bipolar device described in this implementation mode is provided with a high doping concentration region centered on the emitter region on the surface of the base region. The doping concentration of the doping concentration region is 10-10000 times of the doping concentration of the body region.

The optimal range of the doping concentration of the high doping concentration region is 10 to 10000 times the doping concentration of the body region.

The radiation-resistant bipolar device described in this embodiment forms a high doping concentration region around the emitter region on the surface of the base region without affecting the electrical performance parameters of the device. As shown in Figure 4, after radiation damage, the high doping concentration region on the surface of the base region hinders the expansion of the depletion layer, thereby reducing the recombination number of carriers in the depletion region and reducing the radiation of bipolar devices. According to the degree of damage. This structure can greatly reduce the influence of positive charges captured by oxides on device performance, and improve the radiation resistance of bipolar devices. After testing, the failure threshold of bipolar transistors with the above-mentioned high doping concentration region is 1.4 to 3.7 times higher .

The application objects of the above-mentioned anti-radiation bipolar devices include NPN devices, PNP devices, digital bipolar circuits, analog bipolar circuits and digital-analog/analog-digital circuits.

Specific Embodiment 2: This embodiment is described in conjunction with FIG. 2 and FIG. 5. This embodiment is a further limitation of the radiation-resistant bipolar device described in Embodiment 1. In this embodiment, the high doping concentration region It is a polycyclic high doping concentration region.

It can be seen from FIG. 5 that, compared with the traditional base structure, the failure threshold of the bipolar transistor with multi-ring high doping concentration regions is 3.7 times higher.

Specific embodiment three: This embodiment is a further limitation of the radiation-resistant bipolar device described in embodiment two. In this embodiment, the depth of the multi-ring high doping concentration region is 1% of the depth of the emitter region. /20～1/5, the width of the ring is 0.01～10μm, the minimum distance between the boundary of the inner ring and the boundary of the emission area is 0.01～10μm, the distance between two adjacent rings is 0.1～10μm, and the number of rings is 1～10 indivual.

Specific Embodiment 4: In combination with Figure 3 and Figure 5, this embodiment is a further limitation of the radiation-resistant bipolar device described in Embodiment 1. In this embodiment, the high doping concentration region is a rectangular grid High doping concentration region.

It can be seen from FIG. 5 that, compared with the traditional base structure, the failure threshold of the bipolar transistor with the rectangular grid-like high doping concentration region is 3.9 times higher.

Specific implementation mode five: this implementation mode is a further limitation on the radiation-resistant bipolar device described in implementation mode four. 1/20 to 1/5, the length and width of the rectangular grid are both 0.01 to 10 μm, the minimum distance between the rectangular grid and the boundary of the emission area is 0.01 to 10 μm, and the distance between two adjacent rectangular grids is 0.1 to 10 μm. Both the number of rows and the number of columns of the grid are 2 to 100.

Embodiment 6: This embodiment is described in conjunction with FIG. 5. This embodiment is the preparation method of the radiation-resistant bipolar device described in Embodiment 1. After the base diffusion or ion implantation is completed, the emitter diffusion or ion implantation is performed. Before injecting, carry out anti-radiation strengthening method, described anti-radiation strengthening method realizes through the following steps:

Step 1. On the basis of the mask of the base region, prepare a doped mask on the surface of the base region;

Step 2: Based on the surface doping mask, implant the same impurity ions into the surface of the base region as in the body of the base region, the implantation depth is 1/20-1/5 of the depth of the emission region, and the implantation concentration is 10-10000 of the concentration of the body region times;

Step 3: After the implantation is completed, perform annealing treatment, the annealing temperature is the same as the annealing temperature during the diffusion or implantation of the base body, and the annealing time is the same as the annealing time during the diffusion or implantation of the base body.

The preparation method of the irradiated bipolar device described in this embodiment is improved on the basis of the traditional bipolar device manufacturing process steps. , to prepare a doping mask on the surface of the base region, and the shape of the mask is determined according to actual needs. The radiation-resistant bipolar device prepared by the above method can greatly reduce the impact of ionizing radiation-induced positive charge capture by oxides, greatly enhance the radiation resistance of the bipolar device, and reduce the damage of the bipolar device under irradiation conditions. Performance degradation is of great significance, and it has obvious advantages and broad application prospects in the application of anti-radiation strengthening technology for bipolar devices.

The optimal range of the doping concentration of the high doping concentration region is 10 to 10000 times the doping concentration of the body region. Figure 5 shows the relationship between the current gain of the radiation-resistant bipolar transistor prepared by the above-mentioned method and the absorbed dose. The experiment selects Co60 radiation source, the dose rate is 0.1rad/s, the total dose is 100krad, and the current gain change is -60 as the failure criterion. It can be seen from FIG. 5 that, compared with the traditional base structure, the failure threshold of the bipolar transistor with the highly doped region is 1.4 to 3.7 times higher. It can be seen that due to the existence of the high doping concentration region on the surface of the base region, the damage degree of the current gain will be reduced, and the radiation resistance of the bipolar device can be improved.

Specific Embodiment 7: This embodiment is described in conjunction with FIG. 5. This embodiment is a further limitation on the preparation method of the radiation-resistant bipolar device described in Embodiment 6. In this embodiment, the surface of the base region described in step 1 The doping mask is a multi-ring mask.

It can be seen from FIG. 5 that, compared with the traditional base structure, the failure threshold of the bipolar transistor with multi-ring high doping concentration regions is 3.7 times higher.

Embodiment 8: This embodiment is a further limitation on the preparation method of the radiation-resistant bipolar device described in Embodiment 7. In this embodiment, the ring width of the multi-ring mask is 0.01- 10 μm, the minimum distance between the boundary of the inner ring and the boundary of the emission area is 0.01-10 μm, the distance between two adjacent rings is 0.1-10 μm, and the number of rings is 1-10.

Specific Embodiment 9: This embodiment is described in conjunction with FIG. 5. This embodiment is a further limitation on the preparation method of the radiation-resistant bipolar device described in Embodiment 6. In this embodiment, the surface of the base region described in step 1 The doping mask is a rectangular grid mask.

It can be seen from FIG. 5 that, compared with the traditional base structure, the failure threshold of the bipolar transistor with the rectangular grid-like high doping concentration region is 3.9 times higher.

Embodiment 10: This embodiment is a further limitation on the preparation method of the radiation-resistant bipolar device described in Embodiment 9. In this embodiment, the length of the rectangular grid of the rectangular grid mask is The width and width are both 0.01-10 μm, the minimum distance between the rectangular grid and the boundary of the emission area is 0.01-10 μm, the distance between two adjacent rectangular grids is 0.1-10 μm, and the number of rows and columns of the grid is 2-100 .

Embodiment 11: This embodiment is described in conjunction with FIG. 6. This embodiment is a further limitation of the radiation-resistant bipolar device described in Embodiment 1. In this embodiment, the high doping concentration region is more than In the ring type high doping concentration region, the doping concentration is 10 times that of the body region.

The Co60 irradiation source was selected for the experiment, the dose rate was 0.5rad/s, the total dose was 100krad, and the current gain change was -60 as the failure criterion. Figure 6 shows the relationship between the current gain of the bipolar transistor and the absorbed dose under the condition that the high doping concentration region exists. It can be seen from Figure 6 that when the doping concentration of the highly doped region is 10 times that of the body region, the failure threshold of the bipolar transistor with the highly doped region is 1.4 times higher than that of the traditional base region structure . It can be seen that due to the existence of the high doping concentration region on the surface of the base region, the damage degree of the current gain will be reduced, and the radiation resistance of the bipolar device can be improved.

Specific Embodiment Twelve: This embodiment is described in conjunction with FIG. 6. This embodiment is a further limitation of the radiation-resistant bipolar device described in Embodiment 1. In this embodiment, the high doping concentration region is more than In the ring type high doping concentration region, the doping concentration is 1000 times that of the body region.

The Co60 irradiation source was selected for the experiment, the dose rate was 0.5rad/s, the total dose was 100krad, and the current gain change was -60 as the failure criterion. Figure 6 shows the relationship between the current gain of the bipolar transistor and the absorbed dose under the condition that the high doping concentration region exists. It can be seen from Figure 6 that when the doping concentration of the high doping concentration region is 1000 times that of the body region, compared with the traditional base structure, the failure threshold of the bipolar transistor with the high doping region is 2.0 times higher . It can be seen that due to the existence of the high doping concentration region on the surface of the base region, the damage degree of the current gain will be reduced, and the radiation resistance of the bipolar device can be improved.

Specific Embodiment Thirteen: This embodiment is described in conjunction with FIG. 6. This embodiment is a further limitation of the radiation-resistant bipolar device described in Embodiment 1. In this embodiment, the high doping concentration region is more than In the ring type high doping concentration region, the doping concentration is 10,000 times that of the body region.

The Co60 irradiation source was selected for the experiment, the dose rate was 0.5rad/s, the total dose was 100krad, and the current gain change was -60 as the failure criterion. Figure 6 shows the relationship between the current gain of the bipolar transistor and the absorbed dose under the condition that the high doping concentration region exists. It can be seen from Figure 6 that when the doping concentration of the highly doped region is 10,000 times that of the body region, compared with the traditional base structure, the failure threshold of the bipolar transistor with the highly doped region is 3.7 times higher . It can be seen that due to the existence of the high doping concentration region on the surface of the base region, the damage degree of the current gain will be reduced, and the radiation resistance of the bipolar device can be improved.

Claims (8)

1. a kind of Flouride-resistani acid phesphatase bipolar device, is provided with the high-dopant concentration area centered on launch site, described height in base region surface The doping content of concentration doped region is 10～10000 times of body area doping content；

Described high-dopant concentration area is polycycle high-dopant concentration area；

It is characterized in that：The depth in described polycycle high-dopant concentration area is the 1/20～1/5 of launch site depth, the width of ring For 0.01～10 μm, the minimum range far from launch site border for the internal ring border is 0.01～10 μm, and the spacing of two neighboring ring is 0.1 ～10 μm, the number of ring is 1～10.

2. a kind of Flouride-resistani acid phesphatase bipolar device, is provided with the high-dopant concentration area centered on launch site, described height in base region surface The doping content of concentration doped region is 10～10000 times of body area doping content；

Described high-dopant concentration area is rectangular cells formula high-dopant concentration area；

It is characterized in that：The depth in described rectangular cells formula high-dopant concentration area is the 1/20～1/5 of launch site depth, long The length and width of square grid is 0.01～10 μm, and rectangular cells are 0.01～10 μ away from launch site border minimum range M, the spacing of two neighboring rectangular cells is 0.1～10 μm, and the line number of grid and columns are 2～100.

3. a kind of Flouride-resistani acid phesphatase bipolar device described in claim 1 preparation method it is characterised in that：Complete base diffusion or After ion implanting, before carrying out launch site diffusion or ion implanting, carry out radiation hardened method, described radiation hardened method Realized by following steps：

Step one, on the basis of base mask plate, prepare base region surface doping mask plate；

Step 2, based on this surface doping mask plate to base region surface injection and identical foreign ion in base body, injection is deep Spend 1/20～1/5 for launch site depth, implantation concentration is 10～10000 times of body area concentration；

Step 3, complete injection after, made annealing treatment, annealing temperature bulk diffusion with base or inject when annealing temperature phase With annealing time when annealing time is bulk diffusion with base or injects is identical.

4. a kind of Flouride-resistani acid phesphatase bipolar device according to claim 3 preparation method it is characterised in that：Described in step Base region surface doping mask plate is polycycle mask plate.

5. a kind of Flouride-resistani acid phesphatase bipolar device according to claim 4 preparation method it is characterised in that：Described polycycle The width of the ring of mask plate is 0.01～10 μm, and the minimum range far from launch site border for the internal ring border is 0.01～10 μm, adjacent The spacing of two rings is 0.1～10 μm, and the number of ring is 1～10.

6. a kind of Flouride-resistani acid phesphatase bipolar device described in claim 2 preparation method it is characterised in that：Complete base diffusion or After ion implanting, before carrying out launch site diffusion or ion implanting, carry out radiation hardened method, described radiation hardened method Realized by following steps：

Step one, on the basis of base mask plate, prepare base region surface doping mask plate；

Step 2, based on this surface doping mask plate to base region surface injection and identical foreign ion in base body, injection is deep Spend 1/20～1/5 for launch site depth, implantation concentration is 10～10000 times of body area concentration；

Step 3, complete injection after, made annealing treatment, annealing temperature bulk diffusion with base or inject when annealing temperature phase With annealing time when annealing time is bulk diffusion with base or injects is identical.

7. a kind of Flouride-resistani acid phesphatase bipolar device according to claim 6 preparation method it is characterised in that：Described in step Base region surface doping mask plate is rectangular cells formula mask plate.

8. a kind of Flouride-resistani acid phesphatase bipolar device according to claim 7 preparation method it is characterised in that：Described rectangle The length and width of the rectangular cells of grid type mask plate is 0.01～10 μm, and rectangular cells are minimum away from launch site border Distance is 0.01～10 μm, and the spacing of two neighboring rectangular cells is 0.1～10 μm, the line number of grid and columns be 2～ 100.