Trench gate floating island IGBT

Abstract

The invention discloses a trench gate floating island IGBT which comprises an emitter, an N-type drift region, a trench gate, an N + drain, a P + base region, a P + collector and a collector, the emitter, the N-type drift region, the P + collector and the collector are sequentially stacked, a floating island is arranged on one side of the N-type drift region, the floating island and the trench gate are located on the opposite sides of the N-type drift region respectively and are arranged in parallel, and the trench gate is arranged on the other side of the N-type drift region. A relatively simple process is adopted, and while the IGBT has the same breakdown voltage characteristic as a traditional IGBT, the length of the N-type drift region is reduced, so that the overall size length is reduced, and low resistance is ensured.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor detection technology, and in particular to a trench gate floating island IGBT. Background Art

[0002] Usually, in order to ensure the high step-down characteristics of IGBT components, the technology of reducing the impurity doping concentration of the N-type drift region is adopted. This technology can increase the maximum step-down voltage of the component, but the increased voltage drop in the on-state also increases unnecessary power consumption. In order to ensure a higher step-down voltage, the extension of the length of the N-type drift region is inevitable. With this trend, the voltage drop caused by the on-state resistance also increases, and the power consumption is bound to increase. In order to improve the relationship that the higher the voltage drop, the lower the resistivity of the power semiconductor component, the super junction structure and the floating island structure are proposed, but the super junction structure requires a higher level of engineering technology than the floating island structure;

[0003] Therefore, the present application proposes a trench gate floating island IGBT that has a relatively simple process and at the same time has the same breakdown voltage characteristics as a traditional IGBT, and reduces the overall length, thereby ensuring a low resistance. Summary of the invention

[0004] The purpose of the present invention is to provide a trench gate floating island IGBT in view of the technical problems existing in the background technology.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A trench gate floating island IGBT comprises an emitter, an N-type drift region, a trench gate, an N+ drain, a P+ base region, a P+ collector and a collector, wherein the emitter, the N-type drift region, the P+ collector and the collector are stacked in sequence, the trench gate is arranged at a first side between the emitter and the N-type drift region, the P+ base region is arranged at a second side between the emitter and the N-type drift region, the N+ drain is wrapped in the P+ base region, the adjacent two sides of the N+ drain are respectively attached to the emitter and the trench gate, a floating island is arranged at one side of the N-type drift region, and the floating island and the trench gate are respectively located at opposite sides of the N-type drift region and are arranged in parallel.

[0007] Preferably, the distance between the floating island and the emitter is 75 μm, and the dose in the floating island is 5.0X1012cm -2 , the width of the floating island is 6.5μm, and the mask width of the floating island is 3.75μm.

[0008] Preferably, the depth and width of the trench gate are 4 μm and 10 μm respectively.

[0009] Preferably, the cell pitch of the trench gate floating island IGBT is 15 μm.

[0010] Preferably, the depth of the P+ base region is 2.7 μm.

[0011] Preferably, the outer wall of the trench gate is covered with an oxide gate.

[0012] Preferably, the depth of the N-type drift region is 180 μm.

[0013] Preferably, the resistivity of the N-type drift region is 35Ωcm.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: it includes an emitter, an N-type drift region, a trench gate, an N+ drain, a P+ base region, a P+ collector and a collector, the emitter, the N-type drift region, the P+ collector and the collector are stacked in sequence, a floating island is arranged at one side of the N-type drift region, the floating island and the trench gate are respectively located on the opposite side of the N-type drift region and are arranged in parallel, so that a relatively simple process is adopted, while having the same breakdown voltage characteristics as the traditional IGBT, the length of the N-type drift region is reduced and the overall size length is reduced, thereby ensuring low resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0016] Figure 2 It is a schematic diagram of the structure of the planar gate floating island IGBT in the control group in the embodiment of the present invention;

[0017] Figure 3 A schematic diagram of the structure of a traditional IGBT in a control group in an embodiment of the present invention;

[0018] Figure 4 Graph showing the relationship between the resistivity and breakdown voltage of the N-type drift region in the trench gate floating island IGBT and the planar gate floating island IGBT in the embodiment of the present invention;

[0019] Figure 5 A 3D electric field distribution diagram of an embodiment of the present invention;

[0020] Figure 6 3D electric field distribution diagram of the planar gate floating island IGBT in the control group in the embodiment of the present invention;

[0021] Figure 7 3D electric field distribution diagram of the traditional IGBT in the control group in the embodiment of the present invention.

[0022] Figure numbers: 100 emitter, 200N-type drift region, 300 trench gate, 400N+drain, 500P+base region, 600P+collector, 700 collector, 800 floating island, 900 oxide gate. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or a specific connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0026] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] like Figure 1 As shown, the present invention proposes a trench gate floating island IGBT, which includes an emitter 100, an N-type drift region 200, a trench gate 300, an N+ drain 400, a P+ base region 500, a P+ collector (600) and a collector 700;

[0028] Specifically, the trench gate floating island IGBT uses a 1200V IGBT structure, and the voltage drop in the on state is 2.0V, and the current is 100A / cm 2 The current is used as the reference.

[0029] The emitter 100, the N-type drift region 200, the P+ collector 600 and the collector 700 are stacked in sequence, the trench gate 300 is arranged at a first side between the emitter 100 and the N-type drift region 200, the P+ base region 500 is arranged at a second side between the emitter 100 and the N-type drift region 200, the N+ drain 400 is wrapped in the P+ base region 500, and the adjacent two sides of the N+ drain 400 are respectively attached to the emitter 100 and the trench gate 300;

[0030] A floating island 800 is disposed at one side of the N-type drift region 200 . The floating island 800 and the trench gate 300 are respectively located at opposite sides of the N-type drift region 200 and are disposed in parallel.

[0031] The width of the floating island 800 is 6.5μm, the depth and width of the trench gate 300 are 4μm and 10μm respectively, the cell pitch of the trench gate 300 gate floating island IGBT is 15μm, the depth of the P+ base region 500 is 2.7μm, the outer wall of the trench gate 300 is covered with an oxide gate, the depth of the N-type drift region 200 is 180μm, and the resistivity of the N-type drift region 200 is 35Ωcm.

[0032] Specifically, the trench gate floating island IGBT in this embodiment and the planar gate floating island IGBT of another structure (see the attached Figure 2 ) is designed, and the design parameters are shown in Table 1;

[0033] Table 1 is as follows:

[0034]

[0035] From Table 1, we can see that the distance between the floating island 800 and the emitter 100 is 75 μm, and the dose inside the floating island 800 is 5.0X10 12 cm -2 The mask width of the floating island 800 is 3.75 μm and the other structural settings are the same, only the setting depth of the trench gate 300 is different. The depth of the trench gate 300 of the trench gate floating island IGBT in the present invention is 4 μm, while the depth of the trench gate in the IGBT of another structure is 0, wherein the setting of the depth of the trench gate 300 is obtained by comparing Table 2.

[0036] Table 2 is as follows:

[0037]

[0038] It can be seen from Table 2 that when the N-type drift region 200 is at a quantitative value of 60Ωcm, the breakdown voltage varies with the depth of the trench gate 300, and when the depth of the trench gate 300 is selected to be 4μm, the trench gate floating island IGBT can have the characteristic of high breakdown voltage.

[0039] Table 3 is as follows:

[0040]

[0041] In this embodiment, a conventional IGBT (see Appendix) is added again. Figure 3 ) structure is designed, in which the parameter structure is roughly the same as the trench gate floating island IGBT and the planar gate floating island IGBT in Table 1, in order to control the variables. As shown in Table 3, the breakdown voltage of the trench gate floating island IGBT is 1281V and the voltage drop is 2.0V.

[0042] See attached Figure 4 The figure shows the variation of the dose concentration of the N-type drift region 200 and the breakdown voltage under different parameters in the trench gate floating island IGBT and the planar gate floating island IGBT. It can be seen that under the same breakdown voltage, the corresponding dose concentration of the N-type drift region 200 is also different, as shown in Table 4.

[0043] Table 4 is as follows:

[0044]

[0045] like Figure 4 The relationship between the resistivity and breakdown voltage of the N-type drift region 200 in the planar gate floating island IGBT and the trench gate floating island IGBT is shown. Under the same conditions, the breakdown voltage characteristic decreases because the electric field applied to the device is unevenly distributed throughout the device. In particular, when too much electric field is applied and reaches the critical electric field, breakdown will occur.

[0046] according to Figure 4 As shown in Table 4, the resistivity of the N-type drift region 200 in the planar gate floating island IGBT and the trench gate floating island IGBT is adjusted to 40Ωcm and 35Ωcm, respectively. It should be noted that each IGBT needs to be charged at 100A / cm 2 As a benchmark, it can be seen that the trench gate floating island IGBT has higher breakdown voltage characteristics and lower voltage drop than the other two IGBTs.

[0047] Table 5 is as follows:

[0048]

[0049] like Figure 5-Figure 7, the applied electric field distribution of each IGBT is displayed in 3D. It can be seen here that the highest point of the electric field applied to the device is separated by the floating island 800 structure, and the slope of the electric field increases. Therefore, in the Turn-off state, the length of the depletion layer generated on the N-type drift region 200 of the device will be reduced. As shown in Table 5, the depletion layer lengths generated by the traditional IGBT, the planar gate floating island IGBT and the trench gate floating island IGBT are 160μm, 150μm and 140μm, respectively. In other words, the length of the depletion layer subjected to the same step-down voltage will be reduced, so that the length of the N-type drift region of the device can be reduced, thereby reducing the resistance of the device and reducing unnecessary power consumption.

[0050] At the same time, it can be seen from the trench gate floating island IGBT that the oxide gate 900 is subjected to a large electric field, such as Figure 5 As shown. This is because the electric field of the trench gate 300 is particularly concentrated. Among them, the silicon oxide surrounding the trench gate 300 can withstand higher voltages, and even the critical electric field that the silicon oxide withstands is usually dozens of times higher than that of silicon. As a result, a breakdown voltage value characteristic of about 20V higher than other devices is obtained. In order to improve the electrical characteristics of the IGBT with the floating island 800, a trench gate 300 structure is proposed, and its breakdown voltage and on-state voltage drop characteristics are simulated and analyzed. The results show that for the optimization of the resistance component of only N-type JFET, for industrial IGBTs, even if the floating island 800 is introduced, its effect is minimal. Therefore, the result we have obtained is that when the trench gate 300 and the floating island 800 are combined in the same IGBT to form a trench gate floating island IGBT, it not only has the same voltage reduction characteristics, but also can further reduce the length of the device to ensure lower resistance.

[0051] The above is a trench gate floating island IGBT or multiple implementations provided in combination with specific content, and it is not intended that the specific implementation of the present invention is limited to these descriptions. Any similarity or similarity with the method, structure, etc. of the present invention, or any technical deduction or replacement based on the concept of the present invention, shall be regarded as the protection scope of the present invention.

Claims

1. A trench gate floating island IGBT, It is characterized in that include: An emitter (100), an N-type drift region (200), a trench gate (300), an N+ drain (400), a P+ base region (500), a P+ collector (600), and a collector (700); The emitter (100), the N-type drift region (200), the P+ collector (600) and the collector (700) are stacked in sequence, the trench gate (300) is arranged at a first side between the emitter (100) and the N-type drift region (200), the P+ base region (500) is arranged at a second side between the emitter (100) and the N-type drift region (200), the N+ drain (400) is wrapped in the P+ base region (500), and the adjacent two sides of the N+ drain (400) are respectively attached to the emitter (100) and the trench gate (300); A floating island (800) is arranged at one side of the N-type drift region (200), and the floating island (800) and the trench gate (300) are respectively located at opposite sides of the N-type drift region (200) and are arranged in parallel.

2. The trench gate floating island IGBT according to claim 1, It is characterized in that The distance between the floating island (800) and the emitter (100) is 75 μm, and the dose in the floating island (800) is 5.0×10 12 cm -2 , the width of the floating island (800) is 6.5 μm, and the width of the mask of the floating island (800) is 3.75 μm.

3. The trench gate floating island IGBT according to claim 1, It is characterized in that The depth and width of the trench gate (300) are 4 μm and 10 μm respectively.

4. The trench gate floating island IGBT according to claim 1, It is characterized in that The cell pitch of the trench gate (300) gate floating island IGBT is 15 μm.

5. The trench gate floating island IGBT according to claim 1, It is characterized in that The depth of the P+ base region (500) is 2.7 μm.

6. The trench gate floating island IGBT according to claim 1, It is characterized in that The outer wall of the trench gate (300) is covered with an oxide gate.

7. The trench gate floating island IGBT according to claim 1, It is characterized in that The depth of the N-type drift region (200) is 180 μm.

8. The trench gate floating island IGBT according to claim 1, It is characterized in that The resistivity of the N-type drift region (200) is 35Ωcm.

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