Insulated gate bipolar transistor including first and second field stop regions and method of manufacturing the same

Abstract

The present invention relates to an insulated gate bipolar transistor including first and second field stop region portions and a manufacturing method. An embodiment relates to a method of manufacturing an insulated gate bipolar transistor in a semiconductor body. A first field stop region portion of a first conductivity type is formed on a semiconductor substrate. A second field stop region portion of the first conductivity type is formed on the first field stop region portion. A drift region of the first conductivity type is formed on the second field stop region portion. When the insulated gate bipolar transistor is completed, a vertical extension of more than 30% of the thickness of the semiconductor body, a doping concentration in the drift region is less than 10<supgt;13< / supgt; cm<supgt;‑3< / supgt>.

Description

Technical Field

[0001] The present disclosure relates to an insulated gate bipolar transistor and a manufacturing method including first and second field stop region portions. Background Art

[0002] Insulated gate bipolar transistors (IGBTs) are designed to meet various requirements, such as those related to operating losses, blocking voltages, oscillatory behavior during turn-off, and cosmic ray robustness. When certain device characteristics are improved by adjusting specific layout parameters, this may result in negative impacts on other device characteristics. Therefore, IGBT design may require a trade-off between the requirements for different device characteristics.

[0003] Accordingly, it is desirable to improve insulated gate bipolar transistors and methods of manufacturing insulated gate bipolar transistor semiconductors including field stop regions, which allow for an improved trade-off between device characteristics. Summary of the Invention

[0004] The present disclosure relates to a method of manufacturing an insulated gate bipolar transistor in a semiconductor body. The method includes: forming a first field stop region portion of a first conductivity type on a semiconductor substrate. The method further includes: forming a second field stop region portion of the first conductivity type on the first field stop region portion. The method further includes: forming a drift region of the first conductivity type on the second field stop region portion. When the insulated gate bipolar transistor is completed, along a vertical extension of more than 30% of the thickness of the semiconductor body, the doping concentration in the drift region is less than 10 13 cm -3 .

[0005] The present disclosure relates to an insulated gate bipolar transistor. The insulated gate bipolar transistor includes a drift region of a first conductivity type in a semiconductor body. The insulated gate bipolar transistor further includes the first field stop region portion of the first conductivity type in the semiconductor body. The insulated gate bipolar transistor further includes: the second field stop region portion of the first conductivity type in the semiconductor body, located between the drift region and the first field stop region portion. Along a vertical extension of more than 30% of the thickness of the semiconductor body, the doping concentration in the drift region is less than 10 13 cm -3 .

[0006] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description and upon viewing the drawings. Brief Description of the Drawings

[0007] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. As other embodiments of the present invention and the expected advantages become better understood with reference to the following detailed description, they will be readily appreciated.

[0008] Figure 1 is a flowchart illustrating an example of manufacturing an insulated gate bipolar transistor.

[0009] Figures 2 to 4 is a cross-sectional view illustrating an example of an insulated gate bipolar transistor.

[0010] Figure 5 is a schematic curve graph illustrating the variation of the turn-off energy loss Eoff with respect to the conduction loss quantified by the collector-emitter saturation voltage Vcesat of the IGBT.

[0011] Figure 6 is a curve graph illustrating the variation of the collector-emitter voltage Vce with respect to time for different collector-emitter voltage levels of the IGBT.

[0012] Figure 7 is a curve graph illustrating the variation of the failure rate FIT hours with respect to the collector voltage Vce of the IGBT. Detailed Description

[0013] In the following detailed description, reference is made to the accompanying drawings, which form a part of the following detailed description and in which are shown by way of illustration specific embodiments in which the present disclosure may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. For example, features illustrated or described for one embodiment may be used on or in combination with other embodiments to yield yet another embodiment. It is intended that the present disclosure include such modifications and variations. The examples are described using specific language that should not be construed as limiting the scope of the appended claims. The accompanying drawings are not drawn to scale and are for illustrative purposes only. For clarity, the same elements have been designated by corresponding reference numerals in different drawings, if not otherwise stated.

[0014] The terms "having", "comprising", "including", "containing", etc. are open and these terms indicate the presence of the stated structure, element or feature, but do not preclude the presence of additional elements or features. The articles "a", "an" or "the" are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.

[0015] The term "electrically coupled" includes that one or more intermediate elements adapted for signal transmission may be present between the electrically coupled elements, such as elements that temporarily provide a low-ohm connection in a first state and temporarily provide a high-ohm electrical decoupling in a second state.

[0016] Each figure illustrates the relative doping concentration by indicating "-" or "+" next to the doping type "n" or "p". For example, "n - " means a doping concentration lower than that of the "n" doped region, while the "n + " doped region has a doping concentration higher than that of the "n" doped region. Doped regions with the same relative doping concentration do not necessarily have the same absolute doping concentration. For example, two different "n" doped regions may have the same or different absolute doping concentrations. As used in this specification, the term "horizontal" is intended to describe an orientation that is substantially parallel to the first surface or the main surface of the semiconductor substrate or body. This may be, for example, the surface of a wafer or a die.

[0017] As used in this specification, the term "vertical" is intended to describe an orientation that is arranged substantially perpendicular to the first surface (i.e., parallel to the normal direction of the first surface of the semiconductor substrate or body).

[0018] In this specification, the second surface of the semiconductor substrate or semiconductor body is considered to be formed by the lower surface or the back surface, while the first surface is considered to be formed by the upper surface, the front surface, or the main surface of the semiconductor substrate. The terms "above" and "below" as used in this specification thus describe the relative position of one structural feature with respect to another structural feature.

[0019] In this specification, n-doping is referred to as the first conduction type, while p-doping is referred to as the second conduction type. Alternatively, semiconductor devices may be formed with the opposite doping relationship, such that the first conduction type may be p-doped and the second conduction type may be n-doped.

[0020] Figure 1 is a schematic flow chart for illustrating method 1000 of manufacturing an insulated gate bipolar transistor in a semiconductor body. The semiconductor body has opposite first and second surfaces (e.g., the front surface and the back surface), and may include, among other things, and for example, a semiconductor substrate and one or more functional layers, such as (one or more) field stop regions and drift regions on the semiconductor substrate. During the processing of the insulated gate bipolar transistor, the thickness of the semiconductor body may increase due to the deposition of layers on the semiconductor substrate.

[0021] It will be appreciated that although method 1000 is illustrated and described below as a series of acts or events, the illustrated ordering of such acts or events should not be construed in a limiting sense. For example, some acts may occur in a different order and / or concurrently with other acts or events than those illustrated and / or described herein. Additionally, not all of the illustrated acts may be necessary to implement one or more aspects of the embodiments of the disclosure herein. Moreover, one or more of the acts depicted herein may be implemented in one or more separate acts and / or phases.

[0022] Process feature S100 includes: forming a first field stop region portion of a first conductivity type on a semiconductor substrate. In one or more embodiments, a layer growth process such as liquid phase epitaxy (LPE), molecular beam epitaxy (MBE), or chemical vapor deposition (CVD) may be used. In one or more embodiments, in-situ doping during the layer growth process may be used to fully or partially set a target doping profile in the first field stop region portion. One or more doping processes (e.g., diffusion and / or ion implantation processes) may follow to set the doping profile in the first field stop region portion. In one or more embodiments, proton implantation and annealing may be used to set the doping profile in the first field stop region portion. One or more proton implantations may be performed through a second surface (e.g., the back surface of the semiconductor body) after processing one or more of the IGBT components such as the body, source, and gate at a first surface (e.g., the front surface of the semiconductor body).

[0023] The semiconductor substrate may be a semiconductor wafer, such as a silicon wafer. In one or more embodiments, the semiconductor wafer is a silicon wafer obtained by a Czochralski growth process, e.g., a magnetic Czochralski (MCZ) silicon wafer. According to other embodiments, the semiconductor substrate may have another single crystal semiconductor material, such as silicon carbide SiC, gallium arsenide GaAs, gallium nitride GaN, or another A III B V semiconductor, germanium Ge, or silicon germanium crystal SiGe.

[0024] The process feature S110 includes: forming a second field stop region portion of a first conductivity type on a first field stop region portion. Similar to the first field stop region portion, in one or more embodiments, a layer growth process (e.g., liquid phase epitaxy (LPE), molecular beam epitaxy (MBE), or chemical vapor deposition (CVD)) can be used to form the second field stop region portion. In one or more embodiments, in-situ doping during the layer growth process can be used to fully or partially set the target doping profile in the second field stop region portion. One or more doping processes (e.g., diffusion and / or ion implantation processes) can follow to set the doping profile in the first field stop region portion. In one or more embodiments, proton implantation and annealing can be used to set the doping profile in the second field stop region portion. One or more proton implantations can be implemented through a second surface (e.g., the back surface of the semiconductor body) after processing one or more of the body, source, and gate at a first surface (e.g., the front surface of the semiconductor body) of the IGBT device. In one or more embodiments, the first and second field stop region portions can be formed in the same layer growth device (e.g., in the same layer growth reactor such as a low-pressure or atmospheric pressure chemical vapor deposition (LPCVD or APCVD) chamber).

[0025] In one or more embodiments, the maximum doping concentration in the second field stop region portion is set by in-situ doping.

[0026] In one or more embodiments, the maximum doping concentration in the second field stop region portion is set by a doping peak (e.g., a hydrogen-related donor resulting from proton implantation and annealing) caused by the implantation and activation of dopant ions.

[0027] In one or more embodiments, setting the doping concentration in the second field stop region portion includes: setting a constant doping profile along the vertical extension of the second field stop region portion in the range of 4 μm to 15 μm. The constant doping profile can be set, for example, by in-situ doping during layer growth and can enable the relaxation of the electric field strength during the turn-off operation and reduce the oscillation behavior.

[0028] In one or more embodiments, method 1000 further includes: setting the ratio of the average doping concentration in the first field stop region portion to the average doping concentration in the second field stop region portion in the range of 5 to 30, thereby allowing to stop the expansion of the space charge region towards the second surface (e.g., the back surface of the semiconductor body) during the operating conditions of the IGBT.

[0029] The process feature S120 includes: forming a drift region of a first conductivity type on a second field stop region portion. When completing an insulated gate bipolar transistor, a vertical extension of more than 30% or more than 40% or even more than 50% of the thickness of the semiconductor body is provided, and the doping concentration in the drift region is set to be less than 10 13 cm -3 . Thus, this vertical extension corresponds to a vertical section in the drift region that is at least 30% of the thickness of the semiconductor body after the processing of the insulated gate bipolar transistor is completed. Thus, the thickness of the semiconductor body corresponds to the vertical distance between the opposite surfaces of the semiconductor body when the insulated gate bipolar transistor is completed.

[0030] In one or more embodiments, the doping concentration in the drift region is set by the background doping of an epitaxial growth apparatus with the doping gas inlet closed. Thereby, the doping concentration in the drift region can be reduced.

[0031] In one or more embodiments, setting the doping concentration in the drift region further includes reverse doping. By reverse doping, the doping concentration in the drift region can be further reduced. In one or more embodiments, the first and second field stop region portions and the drift region are formed in the same epitaxial growth apparatus. For example, this can allow the doping concentrations of the drift region and the first and second field stop region portions to be set more precisely relative to each other, enabling the electric field distribution to be set more precisely during various operating modes of the device.

[0032] In one or more embodiments, the epitaxial growth apparatus, such as a growth chamber or a growth reactor, is purged with H2 gas between the formation of the second field stop region portion and the drift region. The purging with H2 is used to clean the growth chamber or the growth reactor between the formation of the second field stop region portion and the drift region, enabling a more precise and steeper transition between the doping concentration in the second field stop region portion and the relatively lower doping concentration in the drift region.

[0033] In one or more embodiments, the ratio of the maximum doping concentration in the second field stop region portion to the minimum doping concentration in the drift region is set in the range of 50 to 500 or 20 to 1000. The second field stop region portion allows the expansion of the space charge region through the second field stop region portion and into the first field stop region portion to be slowed down during the turn-off operation of the IGBT.

[0034] In one or more embodiments, the gradient of the doping concentration distribution in the transition region between the first field stop region portion and the second field stop region portion is set to be less than 10 20 dopant atoms / cm -4 . The gradient of the doping concentration distribution in the transition region between the second field stop region portion and the drift region can also be set to be less than 10 20dopant atoms / cm -4 This can allow for improved softness.

[0035] In one or more embodiments, q1 is equal to the integral of the ionized dopant charge along the vertical extent of the first field stop region portion, and q2 is equal to the integral of the ionized dopant charge along the vertical extent of the second field stop region portion, and the doping concentration profiles of the first and second field stop region portions are adjusted to set the ratio of q2 to q1 in the range from 1 to 8.

[0036] The sum of q1 and q2 can be set to be less than the breakdown charge of the semiconductor body, thereby achieving an effective field stop function for the first and second field stop region portions. In one or more embodiments, q1 is set to be less than 60% of the breakdown charge of the semiconductor body.

[0037] In one or more embodiments, the method further includes: thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite the first surface. The material removal can be implemented by using mechanical material removal (e.g., grinding and polishing), chemical etching, plasma etching, or laser ablation. In one or more embodiments, the thinning is implemented after forming the IGBT doping regions at the first surface (e.g., after forming the source region and the body region at the first surface, or after forming the gate electrode(s) and the gate dielectric(s) at the first surface). In one or more embodiments, for example, the thinning is implemented before the ion implantation of dopant ions at a second surface opposite the first surface (e.g., before implanting the dopant ions that constitute the second formed backside emitter region of the IGBT), or before or after the ion implantation of dopant ions for setting the doping profile in the first field stop region portion.

[0038] In one or more embodiments, method 1000 further includes: setting the doping concentration in the top portion of the drift region to be more than 5 times greater than the minimum doping concentration of the drift region. For example, this can allow decoupling of the drift region concentration in the top portion of the drift region on one side and the drift region concentration in the bulk and lower portions of the drift region on the other side, where the top portion may have an impact on channel region characteristics (such as the threshold voltage) or on the voltage blocking capability in the edge termination region, and the bulk and lower portions may have an impact on cosmic ray robustness and operating losses.

[0039] In some embodiments, the IGBT is a power IGBT having: a rated maximum load current greater than 1 A, and a rated load terminal-to-load terminal breakdown voltage greater than 300 V or greater than 400 V or greater than 600 V or greater than 650 V or greater than 900 V or greater than 1000 V or greater than 1200 V or greater than 1600 V or greater than 1700 V or greater than 3300 V or greater than 4500 V (e.g., 6500 V).

[0040] Figure 2 Is a cross-sectional view of a semiconductor body 100 that is an example for illustrating an insulated gate bipolar transistor 1001. Figure 2 The formation of the IGBT 1001 illustrated in may include, for example, process features S100 to S120 described in the flowchart of method 1000 illustrated in Figure 1

[0041] The IGBT 1001 includes an n - -doped drift region 102 in the semiconductor body 100. The IGBT 1001 further includes a first n-doped field stop region portion 104 in the semiconductor body 100. The IGBT 1000 further includes a second n-doped field stop region portion 106 between the drift region 102 and the first field stop region portion 104. With a vertical extension of more than 30% along the thickness of the semiconductor body 100, the doping concentration in the drift region is less than 10 13 cm -3 .

[0042] The IGBT 1001 further includes an IGBT top cell portion 110 adjacent to the first surface 108. In the IGBT top cell portion, a source region, a body region, a body contact region, and a further doped semiconductor region may be formed in any desired top cell design. Depending on the specific top cell design, trenches including (one or more) gate electrodes and optional field electrodes may be arranged partially or completely in the top cell portion 110. In a top cell design including a planar gate electrode, for example, (one or more) gate dielectrics and (one or more) gate electrodes may be formed on the semiconductor body 100 at the first surface 108. Depending on the specific top cell design, the drift region 102 may extend up to the first surface 108, for example, in a planar gate IGBT.

[0043] The IGBT 1001 further includes a p + -doped emitter region 112 at a second surface 114 of the semiconductor body 100 opposite the first surface 108. In one or more embodiments, the IGBT is reverse conducting (i.e., a reverse conducting insulated gate bipolar transistor (RC IGBT)), and further includes an n + adjacent to the second surface 114 between portions of the -doped emitter region 112 + ​Doped region.

[0044] IGBT 1001 further includes a first load terminal contact L1, which is electrically coupled to the semiconductor body 100 at the first surface 108. The IGBT further includes a control terminal contact C, which is electrically coupled to a control electrode, such as a gate electrode in a planar or trench gate structure, at the first surface 108. The IGBT further includes a second load terminal contact L2, which is electrically coupled to the p + doped emitter region 112 at the second surface 114 of the semiconductor body 100. Each of the contacts may include one or more conductive materials, such as metals, alloys, silicides, or highly doped semiconductor materials.

[0045] The simulated distribution of the electric field strength at the blocking voltage Vb along the depth d of the semiconductor body 100 associated with the IGBT 1001 is indicated by c1. The simulated distribution of the electric field strength at the blocking voltage Vb associated with a comparable example of an IGBT having a larger doping concentration in the drift region and a larger substrate thickness is indicated by c2. A vertical extension of more than 30% along the thickness of the semiconductor body 100 reduces the doping concentration in the drift region 102 to less than 10 13 cm -3 of the concentration value allows: due to the reduction of the electric field gradient and due to the reduction of the peak electric field strength in the drift region 102, the thickness of the semiconductor body 100 can be reduced by maintaining cosmic ray robustness. The peak electric field strength Ep2 of the IGBT associated with the distribution c2 is greater than the peak electric field strength Ep1 of the IGBT associated with the distribution c1. Due to the smaller electric field gradient in the drift region 102 of the IGBT 1001, the extension of the space charge region of the IGBT 1001 associated with the distribution c1 at the blocking voltage Vb is smaller than the extension of the space charge region of the IGBT associated with the distribution c2 of the blocking voltage Vb.

[0046] In one or more embodiments, IGBT 1001 further includes a doping concentration in the top portion of the drift region 102 (e.g., in the region of the drift region 102 adjacent to the gate dielectric of a planar or trench gate structure), which is more than 2 times larger than the minimum doping concentration of the drift region 102. For example, this may allow decoupling the drift region concentration in the top portion of the drift region on one side and the drift region concentration in the bulk and lower portions of the drift region on the other side, where the top portion may have an impact on channel region characteristics (such as the threshold voltage) or on the voltage blocking ability in the edge termination region, and the bulk and lower portions may have an impact on cosmic ray robustness and operating losses.

[0047] Figure 3 is a cross-sectional view of a semiconductor body 100 illustrating an example of an insulated gate bipolar transistor 1002. Figure 3The formation of the IGBT 1002 illustrated in the figure may include, for example, process features S100 to S120 described in the flowchart of the method 1000 illustrated in Figure 1 the figure. Figure 2 The IGBT 1001 illustrated in the figure and Figure 3 the IGBT 1002 illustrated in the figure are similar in terms of the presence of structural features (such as, for example, the drift region 102 and the first and second field stop region portions 104, 106 that may be manufactured as described in the method 1000 illustrated in Figure 1 the figure).

[0048] With a vertical extension of more than 30% along the thickness of the semiconductor body 100, the doping concentration of the drift region 102 is less than 10 13 cm -3 . The maximum doping concentration in the first field stop region portion 104 is determined by the first doping peak P1. The first doping peak P1 may be formed by ion implantation and activation (e.g., by proton implantation and annealing). The first doping peak P1 serves to stop the expansion of the space charge region at a high blocking voltage that may occur during the blocking voltage mode or the switching mode. The maximum doping concentration in the second field stop region portion 106 is determined by the second doping peak P2. The second doping peak P2 may be formed by, for example, epitaxy or ion implantation and activation (e.g., by proton implantation and annealing). The second doping peak P2 serves to slow down the expansion of the space charge region into the field stop region in the direction towards the second surface 114. The IGBT 1002 further includes a uniformly or constantly doped distribution section 116 along the vertical extension of the second field stop region portion 106 between the first and second doping peaks P1, P2. The uniformly or constantly doped distribution section 116 may be formed by, for example, in-situ doping during layer growth. The thickness of the uniformly or constantly doped distribution section 116 may be in the range of, for example, 4 μm to 55 μm. The uniformly or constantly doped distribution section 116 serves to enable the relaxation of the electric field strength during turn-off and reduce the oscillation behavior. In one or more embodiments, the ratio of the doping concentration of the constant doping distribution section 116 to the doping concentration of the drift region 102 varies within the range between 20 and 1000. In one or more embodiments, the ratio of the doping concentration of the first doping peak P1 to the doping concentration of the constant doping distribution section 116 varies within the range between 10 and 10 4 .

[0049] The IGBT 1002 further includes a doping concentration in the top portion 118 of the drift region 102 (e.g., in the region of the drift region 102 adjacent to the gate dielectric of the planar gate structure or the trench gate structure), which is greater than the minimum doping concentration of the drift region 102. In Figure 3 the example illustrated in the figure, the doping concentration in the top portion 118 is at 1×10 13cm -3 in the range between 5×10 14 cm -3 In the range between. The top portion may have a vertical extension, for example, in the range of 2 μm to 15 μm or in the range of 3 μm to 10 μm. This may allow decoupling the drift region concentration in the top portion of the drift region on one side from the drift region concentration in the block and the lower portion of the drift region on the other side. The top portion may have an impact on channel region characteristics (such as the threshold voltage), and the block and the lower portion may have an impact on cosmic ray robustness and operating losses.

[0050] In one or more embodiments, the gradient of the doping concentration profile in the first transition region 120 between the constant doping profile section 116 and the first doping peak P1 is set to be less than 10 20 dopant atoms / cm -4 . Similarly, the gradient of the doping concentration profile in the second transition region 121 between the constant doping profile section 116 and the drift region 102 may also be set to be less than 10 20 dopant atoms / cm -4 . This may allow for improved softness.

[0051] Figure 4 is a cross-sectional view of a semiconductor body 100 illustrating an example of an insulated gate bipolar transistor 1003. Figure 4 The formation of the IGBT 1003 illustrated in may include, for example, process features S100 to S120 described in the flowchart of the method 1000 illustrated in Figure 1 . Figure 2 The IGBT 1001 illustrated in and Figure 4 the IGBT 1003 illustrated in are similar in terms of the presence of structural features (such as the drift region 102 and the structural features of the first and second field stop region portions 104, 106 that may be manufactured as described in the method 1000 illustrated in Figure 1 ).

[0052] Except Figure 3 for the structural elements of the IGBT 1002 illustrated in, the IGBT 1003 includes a third doping peak P3 in the second drift region portion 106. The third doping peak P3 is arranged between the first doping peak P1 and the second doping peak P2 and may be formed by ion implantation and activation (for example, by proton implantation and annealing). The third doping peak P3 may serve to adjust the overvoltage peak during turn-off. The doping concentration c between the first doping peak P1 and the third doping peak P3 may be, for example, uniform or constant. Similarly, the doping concentration c between the first doping peak P1 and the third doping peak P3 may be, for example, uniform or constant.

[0053] Figure 2 and 3 The distribution illustrated in is the simulation distribution of IGBTs of equal voltage classes. Figure 4 Voltage classes of 1200 V or higher are mentioned, but Figure 3 the doping distribution in can also be used at higher voltage classes (e.g., up to 6.5 kV).

[0054] Figure 5 is a schematic graph showing the variation of the turn-off energy loss Eoff with respect to the conduction loss quantified by the collector-emitter saturation voltage Vcesat. The data points associated with the IGBTs manufactured by the process features S100 to S120 described by the flowchart of the reference method 1000 are labeled by I1. The thickness of the semiconductor body of the IGBT labeled by I1 is 17% smaller than the thickness of the reference IGBT labeled by Iref. The doping concentration in the drift region of the reference IGBT is greater than 10 13 cm -3 . The IGBTs manufactured by the process features S100 to S120 described by the flowchart of the reference method 1000 allow for a reduction in switching and conduction losses. The improvement in switching and conduction losses does not lead to a deterioration in the oscillation behavior and cosmic ray robustness, as will be referenced Figure 6 and 7 as illustrated. Figure 6 The graph of shows the variation of the collector-emitter voltage Vce with respect to time for different collector-emitter voltage levels. The IGBT labeled by I1 and the reference IGBT labeled by Iref exhibit similar oscillation behavior. Figure 7 The graph of shows the variation of the failure rate FIT rate, as a measure of the number of failures in 109 device hours, with respect to the collector voltage Vce. The IGBT labeled by I1 and the reference IGBT labeled by Iref exhibit similar FIT behavior, with the IGBT labeled by I1 being slightly superior.

[0055] Although specific embodiments have been illustrated and described herein, those skilled in the art will appreciate that various alternative and / or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Accordingly, it is intended that the present invention be limited only by the claims and their equivalents.

Claims

1. A method of manufacturing an insulated gate bipolar transistor in a semiconductor body, the method comprising: Forming a first field stop region portion of a first conductivity type on a semiconductor substrate; Forming a second field stop region portion of the first conductivity type on the first field stop region portion; And The drift region of the first conductivity type is formed on the second field stop region portion, where, when the insulated gate bipolar transistor is completed, it vertically extends more than 30% of the thickness of the semiconductor body, and the doping concentration in the drift region is less than 10 13 cm -3 , and the doping concentration of the remaining portion of the semiconductor body is greater than 10 13 cm -3 , wherein the peak electric field intensity in the drift region is reduced, the electric field gradient in the drift region is reduced to reduce the extension of the space charge region of the insulated gate bipolar transistor, and the thickness of the semiconductor body is reduced by maintaining cosmic ray robustness.

2. The method according to claim 1, wherein the doping concentration in the drift region is set by the background doping of an epitaxial growth apparatus in which all doping gas inlets are closed during the formation of the drift region.

3. The method according to claim 1, wherein setting the doping concentration in the drift region includes reverse doping.

4. The method according to any one of claims 1 to 3, wherein the second field stop region portion and the drift region are formed in the same epitaxial growth apparatus, and the epitaxial growth apparatus is purged with H2 gas between the formation of the second field stop region portion and the drift region.

5. The method according to claim 1, wherein the ratio of the maximum doping concentration in the second field stop region portion to the minimum doping concentration in the drift region is set in the range of 50 to 1000.

6. The method according to any one of claims 1 to 3, wherein the maximum doping concentration in the second field stop region portion is set by in-situ doping.

7. The method according to any one of claims 1 to 3, wherein the maximum doping concentration in the second field stop region portion is set by a doping peak resulting from the implantation and activation of dopant ions.

8. The method according to claim 6, wherein setting the doping concentration in the second field stop region portion includes: Set a constant doping profile along the vertical extension of the second field stop region portion in a thickness range of 4 μm to 55 μm.

9. The method according to claim 8, wherein the ratio of the doping concentration of the constant doping profile to the minimum doping concentration of the drift region varies within a range between 20 and 1000.

10. The method according to any one of claims 1 to 3, further comprising: Set the doping concentration in the top portion of the drift region to more than 2 times the minimum doping concentration of the drift region.

11. The method according to any one of claims 1 to 3, wherein the gradient of the doping concentration distribution in the transition region between the first field stop region portion and the second field stop region portion is set to be less than 10 20 cm -4 .

12. The method according to any one of claims 1 to 3, wherein q1 is equal to the integral of the ionized dopant charge along the vertical extension of the first field stop region portion, and q2 is equal to the integral of the ionized dopant charge along the vertical extension of the second field stop region portion, and the doping concentration profiles of the first and second field stop region portions are adjusted to set the ratio of q2 to q1 in the range from 1 to 8.

13. The method according to claim 12, wherein the sum of q1 and q2 is set to be less than the breakdown charge of the semiconductor body.

14. The method according to claim 12, wherein q1 is set to be less than 60% of the breakdown charge of the semiconductor body.

15. The method according to any one of claims 1 to 3, further comprising: Thin the semiconductor body by removing the material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface.

16. The method according to any one of claims 1 to 3, wherein forming the first field stop region portion includes an epitaxial growth process.

17. The method according to any one of claims 1 to 3, wherein forming the second field stop region portion includes an epitaxial growth process.

18. The method according to any one of claims 1 to 3, wherein forming the drift region includes an epitaxial growth process.

19. An insulated gate bipolar transistor, comprising: a drift region of a first conductivity type in a semiconductor body; a first field stop region portion of the first conductivity type in the semiconductor body; a second field stop region portion of the first conductivity type in the semiconductor body, between the drift region and the first field stop region portion; and wherein When completing the insulated gate bipolar transistor, with a vertical extension of more than 30% along the thickness of the semiconductor body, the doping concentration in the drift region is less than 10 13 cm -3 , and the doping concentration of the remaining part of the semiconductor body is greater than 10 13 cm -3 , wherein the peak electric field intensity in the drift region is reduced, the electric field gradient in the drift region is reduced, to reduce the extension of the space charge region of the insulated gate bipolar transistor, and the thickness of the semiconductor body is reduced by maintaining cosmic ray robustness.

20. The insulated gate bipolar transistor according to claim 19, wherein a ratio of a maximum doping concentration in the second field stop region portion to a minimum doping concentration in the drift region ranges from 20 to 1000.

21. The insulated gate bipolar transistor according to any one of claims 19 to 20, wherein the maximum doping concentration in the second field stop region portion is a doping peak of an implantation profile or an in-situ doping profile.

22. The insulated gate bipolar transistor according to any one of claims 19 to 20, wherein a doping concentration along a vertical extension of the second field stop region portion is constant in a thickness range from 4 μm to 55 μm.

23. The insulated gate bipolar transistor according to claim 22, wherein the maximum doping concentration in the second field stop region portion is a doping peak of an in-situ doping profile or an implantation profile located between the drift region and a constant doping profile in the second field stop region portion.

24. The insulated gate bipolar transistor according to claim 22, wherein a ratio of a doping concentration of the constant doping profile in the second field stop region portion to the minimum doping concentration of the drift region varies within a range between 20 and 1000.

25. The insulated gate bipolar transistor according to any one of claims 19 to 20, wherein a doping concentration in a top portion of the drift region is more than twice the minimum doping concentration of the drift region.

26. The insulated gate bipolar transistor according to any one of claims 19 to 20, wherein the gradient of the doping concentration distribution in the transition region between the first field stop region portion and the second field stop region portion is less than 10 20 cm -4 .

27. The insulated gate bipolar transistor according to any one of claims 19 to 20, wherein q1 is equal to an integral of ionized dopant charges along a vertical extension of the first field stop region portion, and q2 is equal to an integral of ionized dopant charges along a vertical extension of the second field stop region portion, and doping concentration profiles of the first and second field stop region portions are adjusted to set a ratio of q2 to q1 in a range from 1 to 8.

28. The insulated gate bipolar transistor according to claim 27, wherein a sum of q1 and q2 is set to be less than a breakdown charge of the semiconductor body.

29. The insulated gate bipolar transistor according to claim 27, wherein q1 is set to be less than 60% of the breakdown charge of the semiconductor body.

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