A diode device
By employing semiconductor layer structures with different doping types in SJ-diode devices, the resistance is reduced and the charge carriers are rapidly depleted by utilizing the conductivity modulation effect. This solves the problem of large tail current in SJ-diode devices during turn-off, achieving the effects of low on-state voltage and low turn-off energy loss.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU WATECH ELECTRONICS CO LTD
- Filing Date
- 2022-09-09
- Publication Date
- 2026-07-28
AI Technical Summary
Traditional SJ- diode devices have a large tail current during the turn-off process, resulting in significant turn-off energy loss.
By employing semiconductor layer structures with different doping types, including an electric field transition layer, a drift region, and an electric field termination layer, the resistance is reduced when the circuit is turned on through the conductivity modulation effect, and minority carriers are rapidly depleted when the circuit is turned off, thereby reducing the tail current.
It achieves low on-state voltage and low turn-off energy loss at high voltage, ensuring almost no tail current under different voltage conditions, thus improving the performance of the device.
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Figure CN116525644B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power device technology, and more specifically, to a diode device. Background Technology
[0002] Superjunction technology provides a new technical means to improve the performance of power devices. By utilizing staggered N-type and P-type regions, the superjunction structure can flatten and control the electric field in the drift region, effectively reducing the thickness of the drift region in power devices, thereby improving the breakdown voltage of the devices.
[0003] Compared to traditional diodes, SJ-diodes, as a new generation of diodes, offer superior performance characteristics. Lower forward voltage drop, lower switching losses, and higher switching speeds make these devices highly valuable for applications, and their excellent electrical performance has been experimentally verified.
[0004] Traditional SJ- diode devices still suffer from tail current during the turn-off process, resulting in significant turn-off energy loss, which is a technical problem that urgently needs to be solved by those skilled in the art.
[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this application, and therefore may contain information that is not part of the prior art known to those skilled in the art. Summary of the Invention
[0006] This application provides a diode device to solve the technical problem of large turn-off energy loss caused by tail current during the turn-off process in traditional SJ-diode devices.
[0007] This application provides a diode device, including:
[0008] First semiconductor layer of first doping type;
[0009] A first doped type electric field termination layer is formed on the first semiconductor layer;
[0010] A first doped type electric field transition layer is formed on the electric field termination layer;
[0011] A first-doped drift region is formed on the electric field transition layer, and a plurality of second-doped pillar regions are formed in the drift region and spaced apart along the vertical withstand voltage direction;
[0012] A second semiconductor layer of a second doping type is formed above the drift region;
[0013] In this case, the doping concentration of the electric field transition layer is less than the doping concentration of the electric field termination layer. The drift region and the electric field transition layer can respectively accumulate minority carriers through conductivity modulation effect. When the diode device is turned off, the electric field transition layer is completely depleted, and the electric field decreases in the electric field transition layer and decreases to 0 in the electric field termination layer.
[0014] The embodiments of this application, by adopting the above technical solutions, have the following technical effects:
[0015] The doping concentration of the electric field transition layer is lower than that of the electric field termination layer. Of the three layers (drift region, electric field transition layer, and electric field termination layer), only the drift region and the electric field transition layer can accumulate minority carriers through conductivity modulation. However, the electric field termination layer cannot accumulate minority carriers due to conductivity modulation. In other words, the doping concentration of the electric field transition layer is low enough to induce conductivity modulation and accumulate minority carriers, while the doping concentration of the electric field termination layer is high enough to almost completely eliminate conductivity modulation and minority carrier accumulation. When the diode device is turned on, minority carriers injected from the first semiconductor layer into the drift region and the electric field transition layer induce conductivity modulation, reducing their resistance and resulting in a low on-state voltage even at high voltages. This is achieved by reducing the resistance of the drift region and the electric field transition layer through conductivity modulation. Due to the conductivity modulation effect, when a diode is turned on, the first semiconductor layer injects a large number of minority carriers into the drift region and the electric field transition layer for accumulation. When the diode is turned off, the electric field rapidly widens downwards, and the minority carriers stored in the drift region and the electric field transition layer are quickly depleted, meaning the electric field transition layer is completely depleted. The electric field termination layer, due to its high doping concentration, stores almost no minority carriers, resulting in a very small tail current. To quickly deplete the minority carriers accumulated in the electric field transition layer, its thickness needs to be relatively small. A smaller thickness results in fewer minority carriers accumulating within the electric field transition layer, allowing them to be depleted in a shorter time. Therefore, no tail current is generated, leading to lower turn-off energy loss in the diode device. Attached Figure Description
[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0017] Figure 1 This is a schematic diagram of the structure of the diode device according to an embodiment of this application;
[0018] Figure 2 for Figure 1The diagram shows the electric field changes caused by the voltages at the anode and cathode of a diode device with uniformly doped electric field transition layers when it is turned off.
[0019] Figure label:
[0020] In the specific implementation of this application:
[0021] Electric field transition layer 1, drift region 2, pillar region 3, second semiconductor layer 4, second metal layer 5, first metal layer 6, first metal layer 7, epitaxial layer 8, electric field termination layer 9. Detailed Implementation
[0022] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0023] Example 1
[0024] like Figure 1 As shown, the diode device in this embodiment includes:
[0025] First semiconductor layer 6 of the first doping type;
[0026] A first doped type electric field termination layer 9 is formed on the first semiconductor layer;
[0027] A first doped type electric field transition layer 1 is formed on the electric field termination layer;
[0028] A first-doped drift region 2 is formed on the electric field transition layer, and a plurality of second-doped pillar regions 3 are formed in the drift region and spaced apart along the vertical withstand voltage direction;
[0029] A second semiconductor layer 4 of the second doping type is formed above the drift region;
[0030] In this case, the doping concentration of the electric field transition layer is less than the doping concentration of the electric field termination layer. The drift region and the electric field transition layer can respectively accumulate minority carriers through conductivity modulation effect. When the diode device is turned off, the electric field transition layer is completely depleted, and the electric field decreases in the electric field transition layer and decreases to 0 in the electric field termination layer.
[0031] In the diode device of this application embodiment, the doping concentration of the electric field transition layer is lower than that of the electric field termination layer. Only two of the three layers—the drift region, the electric field transition layer, and the electric field termination layer—can accumulate minority carriers through conductivity modulation, while the electric field termination layer cannot accumulate minority carriers. That is, the doping concentration of the electric field transition layer is low enough to allow for conductivity modulation and minority carrier accumulation, while the doping concentration of the electric field termination layer is high enough to almost completely eliminate conductivity modulation and minority carrier accumulation. When the diode device is turned on, minority carriers injected from the first semiconductor layer into the drift region and the electric field transition layer undergo conductivity modulation, reducing their resistance and resulting in a low on-state voltage even at high voltages. In other words, the resistance of the drift region and the electric field transition layer is reduced through conductivity modulation. Due to the conductivity modulation effect, when a diode is turned on, the first semiconductor layer injects a large number of minority carriers into the drift region and the electric field transition layer for accumulation. When the diode is turned off, the electric field rapidly widens downwards, and the minority carriers stored in the drift region and the electric field transition layer are quickly depleted, meaning the electric field transition layer is completely depleted. The electric field termination layer, due to its high doping concentration, stores almost no minority carriers, resulting in a very small tail current. To quickly deplete the minority carriers accumulated in the electric field transition layer, its thickness needs to be relatively small. A smaller thickness results in fewer minority carriers accumulating within the electric field transition layer, allowing them to be depleted in a shorter time. Therefore, no tail current is generated, leading to lower turn-off energy loss in the diode device.
[0032] Alternatively, the first doping type is P-type doping, and the second doping type is N-type doping. In this case, the minority carriers are electrons.
[0033] Alternatively, the first doping type is N-type doping, and the second doping type is P-type doping. Correspondingly, the first semiconductor layer 6 serves as the cathode, the second semiconductor layer 4 serves as the anode, the first metal layer 7 serves as the cathode metal, and the second metal layer 5 serves as the anode metal. In this case, the minority carriers are holes. The diode device of this application embodiment is particularly suitable for the case where the first doping type is N-type doping and the second doping type is P-type doping. Specifically, the electric field transition layer 1 is lightly N-type doped, the drift region 2 is lightly N-type doped, the epitaxial layer 8 is lightly N-type doped, the electric field termination layer 9 is heavily N-type doped, and the first semiconductor layer 6 is heavily N-type doped.
[0034] In practice, when the electric field transition layer is uniformly doped, the thickness of the electric field transition layer ranges from greater than 0 to less than or equal to 2 micrometers.
[0035] This application aims to achieve a diode device with very small or even no current tail when turned off under different voltage conditions, even when the doping of the electric field transition layer is uniform. It assumes that the minimum operating voltage of the diode device is 0.1 BV, the corresponding maximum electric field strength Em is approximately 0.1 Ec, and the electric field strength at the lower boundary of the electric field transition layer is 0.
[0036] According to the formula Em = Q 总 / εs;
[0037] Where εs is the dielectric constant of Si, Ec is the critical breakdown field strength of Si, and Q is the total charge of the electric field transition layer. 总 .
[0038] When Em = 0.1Ec, the doping concentration of the electric field transition layer is at the upper limit of 10. 15 / cm 3 Under these conditions, the maximum value of the electric field transition layer thickness can be obtained as 2 μm.
[0039] When the diode device is turned off, the electric field of the sufficiently thin electric field transition layer 1 rapidly expands downward, and the minority carriers stored in the drift region and transition layer are quickly consumed. However, the electric field termination layer, due to its high doping concentration, hardly stores any minority carriers, thus the tail current becomes very small.
[0040] If the thickness of the electric field transition layer is too large, the electric field may be cut off at the electric field transition layer during turn-off. In this case, the undepleted transition layer will store a large number of minority carriers, which will result in a large tail current when the device is turned off, thereby increasing the turn-off loss of the device.
[0041] In this application, the electric field transition layer is relatively thin, such as Figure 2 As shown, Figure 2 for Figure 1 The diagram shows the electric field changes caused by the voltages at the emitter and collector of a diode device with uniformly doped electric field transition layers when it is turned off. The vertical axis represents... Figure 1 The distance from pit region 7 to drift region 2 is shown on the horizontal axis. Figure 1 The diagram shows the distribution of the actual electric field between the cathode and anode of a diode device as the voltage increases during turn-off. Figure 1 and Figure 2 As shown, the electric field transition layer 1 is thin enough that when the diode device is turned off, the electric field rapidly widens downwards, and the minority carriers stored in the drift region and the transition layer are quickly consumed. However, the electric field termination layer, due to its high doping concentration, hardly stores any minority carriers, so the tail current becomes very small.
[0042] The electric field distribution shows that the electric field of the same device eventually terminates at the electric field termination layer under different voltage conditions. Therefore, regardless of the voltage condition under which the diode device is turned off, the current tail is very small or even non-existent.
[0043] Traditional superjunction devices have their electric field cut off at different locations in the drift region under different voltage conditions. When the voltage is low, the undepleted drift region is wider, which causes current tailing during turn-off. The higher the voltage, the smaller the current tail. Therefore, compared with the traditional superjunction structure, the diode device of this application embodiment can be used at both high and low voltages, and even under low voltage conditions, there is no tail current and the turn-off loss is small.
[0044] In this application, the doping concentration of the electric field termination layer is on the order of 10. 17 / cm 3 Up to 5×10 17 / cm 3 In other words, if the doping concentration of the electric field termination layer is sufficiently high, the electric field termination layer will not exhibit electroconduction modulation effects, meaning that minority carriers will not accumulate within it. The role of the electric field termination layer is simply to linearly reduce the electric field to zero at the termination layer, thus terminating the electric field. In short, the electric field termination layer only serves to quickly terminate the electric field.
[0045] In this application, the doping concentration of the electric field transition layer is on the order of 10. 13 / cm 3 Up to 10 15 / cm 3 Therefore, the electric field transition layer will exhibit a conductivity modulation effect, and at the same time, it can also withstand part of the breakdown voltage.
[0046] Specifically, the electric field terminates within the electric field termination layer, and there is a predetermined distance between the location of the electric field termination within the electric field termination layer and the lower surface of the electric field termination layer to prevent breakdown.
[0047] After the electric field is reduced through the electric field transition layer, it is linearly and rapidly reduced within the electric field termination layer to terminate the electric field.
[0048] Specifically, the thickness of the electric field transition layer is less than the thickness of the electric field termination layer.
[0049] Thus, when the diode device is turned off, the electric field transition layer is completely depleted, requiring a relatively thin layer. Conversely, the electric field termination layer needs to be thick enough to prevent breakdown, requiring a larger thickness. Therefore, the thickness of the electric field transition layer is less than the thickness of the electric field termination layer.
[0050] During implementation, such as Figure 1 As shown, the lower end of the column region 3 is flush with the lower end of the drift region 2, and the lower ends of the column region 3 and the drift region 2 are respectively connected to the upper surface of the electric field transition layer 1.
[0051] During implementation, such as Figure 1 As shown, the diode device also includes:
[0052] The first doped epitaxial layer 8 is formed above the drift region 2 and below the second semiconductor layer 4;
[0053] The upper end of the column region 3 is flush with the upper end of the drift region 2, and the upper ends of the column region 3 and the drift region 2 are respectively connected to the lower surface of the epitaxial layer 8.
[0054] By setting the epitaxial layer 8, the upper, lower, left, and right ends of pillar region 3 are all first-doped regions, thus achieving a floating configuration for pillar region 3. With the pillar region floating, more minority carriers injected into the pillar region by the first semiconductor layer will be stored, resulting in a lower on-state voltage drop.
[0055] During implementation, such as Figure 1 As shown, the diode device also includes:
[0056] The first metal layer 7 is formed under the first semiconductor layer 6.
[0057] The second metal layer 5 is formed on top of the second semiconductor layer 4.
[0058] Specifically, the doping concentration of the electric field transition layer is at least 1 to 1.5 orders of magnitude lower than that of the electric field termination layer.
[0059] Specifically, the doping concentration of the epitaxial layer is less than that of the drift region, and the doping concentration of the epitaxial layer is slightly lower than that of the drift region.
[0060] Specifically, the doping concentration in the drift region is on the order of 10. 14 / cm 3 Up to 10 15 / cm 3 The doping concentration of the pillar region and the doping concentration of the drift region should be on the same order of magnitude, and the charge of the drift region and the pillar region should be equal.
[0061] That is, the drift region and the column region must achieve charge balance.
[0062] Example 2
[0063] In the diode device of Example 2, when the doping of the electric field transition layer is uniform, and the thickness of the electric field transition layer is greater than 0 and less than or equal to 2 micrometers, the electric field transition layer also needs to meet the following requirements.
[0064] During implementation, the doping concentration N of the electric field transition layer is... D The thickness Wp of the electric field transition layer satisfies the following relationship:
[0065] During implementation, the doping concentration N of the electric field transition layer is... D The thickness Wp of the electric field transition layer satisfies the following relationship:
[0066] n%×k%×BV=Em×Wp—q×N D Wp 2 / 2εs;
[0067] Em = k% × Ec;
[0068] Wherein, k% is the percentage of the electric field strength under the minimum preset operating voltage of the diode device to the critical breakdown electric field strength, and the value of the minimum preset operating voltage to the breakdown voltage is taken as the value of k%; n% is the percentage of the voltage borne by the transition layer to the minimum preset operating voltage, and the value of n% is greater than 0% and less than or equal to 5%; Em is the maximum electric field strength corresponding to the minimum preset operating voltage of the diode device, Ec is 0.25 Mv / cm; q is the charge of a single electron; and εs is the dielectric constant of Si.
[0069] Specifically, when n% is 5% and k% is 10%, the above formula corresponds to:
[0070] 5% × 10% × BV = Em × Wp - q × N D Wp 2 / 2εs;
[0071] Em = 10% × Ec;
[0072] Wherein, k% is the percentage of the electric field strength under the minimum preset operating voltage of the diode device to the critical breakdown electric field strength, n% is the percentage of the voltage borne by the transition layer to the minimum preset operating voltage, and the value of n% is greater than 0% and less than or equal to 5%, Em is the maximum electric field strength corresponding to the minimum preset operating voltage of the diode device, Ec is 0.25 Mv / cm, q is the charge of a single electron, and εs is the dielectric constant of Si.
[0073] The 5% × 10% × BV on the left side of the formula represents the voltage that the electric field transition layer can withstand. If the breakdown voltage target for a diode device is 1200 volts, and the minimum preset operating voltage is 10% × BV, then the superjunction structure formed by the drift region and pillar region bears 95% of the minimum preset operating voltage. Therefore, the electric field transition layer bears 5% of the minimum preset operating voltage. The actual voltage borne by the electric field transition layer varies with the layer thickness and doping concentration.
[0074] In implementation, the thickness H of the column region 3 P柱 and the thickness H of epitaxial layer 8 外延层 The sum satisfies the following relationship:
[0075] H P柱+H 外延层 = p% × k% × BV / Em;
[0076] p% + n% = 1;
[0077] 98% ≤ H P柱 / (H P柱 +H 外延层 <100%;
[0078] Where p% is the percentage of the voltage borne by the superjunction region relative to the minimum preset operating voltage.
[0079] Given a fixed diode device, if n% is 5% and k% is 10%, then in the formula: n% × k% × BV = Em × Wp - q × N D Wp 2 / 2εs, Em=k%×Ec; Only the electric field transition layer doping concentration N D The thickness Wp of the electric field transition layer is unknown, while all others are known. This formula represents the doping concentration N of the electric field transition layer. D The relationship between the electric field transition layer thickness Wp and the electric field is as follows. The method used to determine the specific values of both is:
[0080] First, select multiple electric field transition layer thickness Wp values, namely Wp1, Wp2 and Wp3;
[0081] Then, calculate N corresponding to Wp1 according to the formula. D 1. N corresponding to Wp2 D 2. N corresponding to Wp3 D 3;
[0082] Finally, by simulating the three possible values, the diode device with the best performance was selected through simulation.
[0083] The following section discusses the total charge Q of the electric field transition layer based on physical principles. 总 The preset conditions are met, and the doping concentration N of the electric field transition layer is uniformly doped. D The relationship between the thickness Wp of the electric field transition layer and the electric field transition layer is explained by the following formula:
[0084] The electric field intensity E(x) and the total charge Q(x) of the electric field transition layer satisfy the following relationship:
[0085] -dE / dx=-Q(x) / εs
[0086] That is, E(x) = ∫Q(x) / εs×d(x); Formula 1
[0087] Among them, εs is the dielectric constant of Si, and d(x) is the distance between the upper and lower surfaces of the electric field transition layer along the direction of the electric field strength. Formula 1 is a general formula for the electric field strength and total charge of the electric field transition layer.
[0088] This application aims to achieve that when the diode device is turned off under different voltage conditions, the current tail is very small or even non-existent. Assume that the minimum preset operating voltage of the diode device is k%×BV, and the maximum electric field strength Em corresponding to the minimum preset operating voltage of the diode device is approximately k%×Ec. k% is the percentage of the electric field strength under the minimum preset operating voltage condition of the diode device to the critical breakdown electric field strength, that is, the electric field strength on the upper surface of the transition layer is k%×Ec, Ec is the critical breakdown field strength of Si, and εs is the dielectric constant of Si. The critical condition is that the electric field strength on the lower surface of the electric field transition layer is equal to 0. Correspondingly, the total charge Q of the electric field transition layer under the critical condition 临界 . For the specific case where the critical condition is that the electric field strength on the lower surface of the electric field transition layer is equal to 0, Formula 1 can be simplified as:
[0089] k%×Ec = Q 临界 / εs, Formula 2;
[0090] That is, it can be deduced that: Q 临界 = k%×Ec / εs; where εs is the dielectric constant of Si.
[0091] Therefore, the total charge Q of the electric field transition layer 总 should be less than Q 临界 , that is, Q 总 < k%×Ec / εs. Q 总 < k%×Ec / εs is the applicable relationship between the electric field strength and total charge of the electric field transition layer in the specific case where the minimum preset operating voltage of the diode device is k%×BV and the critical condition is that the electric field strength on the lower surface of the electric field transition layer is equal to 0. In this specific case, it not only applies to the case where the doping of the electric field transition layer is uniformly doped, but also applies to the case where the doping of the electric field transition layer is non-uniformly doped. Thus, in the specific case where the minimum preset operating voltage of the diode device is k%×BV and the critical condition is that the electric field strength on the lower surface of the electric field transition layer is equal to 0, the requirement for the total charge Q of the electric field transition layer 总 has been determined.
[0092] On the other hand, when the doping of the electric field transition layer is uniformly doped, the doping concentration N of the electric field transition layer D and the thickness Wp of the electric field transition layer satisfy the following relationship:
[0093] Q 总 = q×N D ×Wp, Formula 3; where q is the charge of a single electron.
[0094] When the doping of the electric field transition layer is linearly variable, the doping concentration N of the electric field transition layer is... D The thickness Wp of the electric field transition layer satisfies the following relationship:
[0095] Q 总 =q×G×Wp 2 / 2, Formula 4;
[0096] Where q is the charge of a single electron, and G is the slope. The value of the slope is adjustable.
[0097] Based on Formulas 1 and 3, we can deduce that: -dE / dx = -Q(x) / εs = -qN D / εs. The thickness of the electric field transition layer is denoted by Wp, then:
[0098]
[0099] Where x takes values from 0 to Wp.
[0100] The electric field strength on the lower surface of the electric field transition layer is denoted by E1, i.e., when E(x) is E1. According to the formula, we can obtain: Em - E1 = q × N D Wp / εs.
[0101] In the specific case where the minimum preset operating voltage of the diode device is k% × BV and the critical condition is that the electric field strength on the lower surface of the electric field transition layer is equal to 0, then Em-E1=Em-0=q×N D Wp / εs, i.e., Em = q × N D Wp / εs.
[0102] Furthermore, since Em is approximately k% × Ec, then k% × Ec = q × N. D Wp / εs. The breakdown voltage is the area below the electric field lines; therefore, the voltage V borne by the transition layer is V = q × N. D Wp 2 / 2εs=n%×k%×BV.
[0103] When the electric field strength is greater than 0 at the lower boundary of the transition layer, E1 = Em - q × N D Wp / εs, at this point the voltage borne by the transition layer is V=Em×W p -q×N D Wp 2 / 2εs=n%×k%×BV;
[0104] Em is the maximum electric field strength corresponding to the minimum preset operating voltage of the diode device. Em is approximately k% × Ec, that is, Em = k% × Ec.
[0105] in:
[0106] k% is the percentage of the electric field strength under the minimum preset operating voltage condition of the diode device relative to the critical breakdown electric field strength. For ease of calculation, the percentage of the minimum preset operating voltage to the breakdown voltage is approximated as k%, that is, the value of the percentage of the minimum preset operating voltage to the breakdown voltage is taken as the value of k%.
[0107] n% is the percentage of voltage borne by the transition layer relative to the minimum preset operating voltage. The value of n% is greater than 0% and less than or equal to 5%. Em is the maximum electric field strength corresponding to the minimum preset operating voltage of the diode device. Ec is 0.25 Mv / cm. q is the charge of a single electron. εs is the dielectric constant of Si.
[0108] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.
[0109] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A diode device, characterized in that, include: First semiconductor layer (6) of first doping type; A first doped type electric field termination layer (9) is formed on the first semiconductor layer. A first doped type electric field transition layer (1) is formed on the electric field termination layer. A first doped drift region (2) is formed on the electric field transition layer, and a plurality of second doped pillar regions (3) are formed in the drift region and spaced apart along the vertical withstand voltage direction. A second semiconductor layer of the second doping type is formed above the drift region (4); In this case, the doping concentration of the electric field transition layer is less than the doping concentration of the electric field termination layer. The drift region and the electric field transition layer can respectively accumulate minority carriers through conductivity modulation effect. When the diode device is turned off, the electric field transition layer is completely depleted, and the electric field decreases in the electric field transition layer and decreases to 0 in the electric field termination layer. When the electric field transition layer is uniformly doped, the doping concentration N of the electric field transition layer is... D The thickness Wp of the electric field transition layer satisfies the following relationship: n%×k%×BV=Em×Wp—q×N D Wp 2 / 2 s; Em = k% × Ec; Where, k% is the percentage of the electric field strength under the minimum preset operating voltage condition of the diode device relative to the critical breakdown electric field strength, and the value of the minimum preset operating voltage relative to the breakdown voltage is used as the value of k%; n% is the percentage of the voltage borne by the transition layer relative to the minimum preset operating voltage, and the value of n% is greater than 0% and less than or equal to 5%; Em is the maximum electric field strength corresponding to the minimum preset operating voltage of the diode device, Ec is 0.25 Mv / cm, and q is the charge of a single electron. is the dielectric constant of Si; The thickness of the electric field transition layer is less than the thickness of the electric field termination layer.
2. The diode device according to claim 1, characterized in that, When the electric field transition layer is uniformly doped, the thickness of the electric field transition layer ranges from greater than 0 to less than or equal to 2 micrometers.
3. The diode device according to claim 2, characterized in that, The doping concentration of the electric field transition layer is on the order of 10. 13 / cm 3 Up to 10 15 / cm 3 ; The doping concentration of the electric field termination layer is on the order of 10. 17 / cm 3 Up to 5×10 17 / cm 3 .
4. The diode device according to claim 2, characterized in that, The lower end of the column region (3) is flush with the lower end of the drift region (2), and the lower ends of the column region (3) and the drift region (2) are respectively connected to the upper surface of the electric field transition layer (1).
5. The diode device according to claim 4, further comprising: An epitaxial layer (8) of the first doped type is formed above the drift region (2) and below the second semiconductor layer (4); The upper end of the column region (3) is flush with the upper end of the drift region (2), and the upper end of the column region (3) and the upper end of the drift region (2) are respectively connected to the lower surface of the epitaxial layer.
6. The diode device of claim 5, wherein, The value of n% is 5%.
7. The diode device according to claim 5, characterized in that, The thickness H of the column region (3) P柱 The thickness H of the epitaxial layer (8) 外延层 The sum satisfies the following relationship: H P柱 +H 外延层 =p%×k%×BV / Em; p%+n%=1; 98%≤H P柱 / (H P柱 +H 外延层 )<100%; Where p% is the percentage of the voltage borne by the superjunction region relative to the minimum preset operating voltage.
8. The diode device according to any one of claims 1 to 7, characterized in that, Also includes: A first metal layer (7) is formed beneath a first semiconductor layer (6); The second metal layer (5) is formed on top of the second semiconductor layer (4).
9. The diode device according to claim 8, characterized in that, The first doping type is N-type doping, and the second doping type is P-type doping. Correspondingly, the first semiconductor layer (6) serves as the cathode, the second semiconductor layer (4) serves as the anode, the first metal layer (7) serves as the cathode metal, and the second metal layer (5) serves as the anode metal. Alternatively, the first doping type is P-type doping, and the second doping type is N-type doping.