TWI747235B - High-voltage semiconductor device - Google Patents

Abstract

High-voltage semiconductor device includes a substrate, a first isolating structure, a gate, a drain region, a source region and a doped region. The substrate has a first conductive type, and the first isolating structure is disposed on the substrate. The drain region is disposed in the substrate and has a second conductive type. The source region is disposed in the substrate and has a first portion and a second portion. The first portion has the second conductive type and the second portion has the first conductive type. The gate is disposed on the substrate, between the source region and the drain region to partially cover a side of the first isolating structure. The doped region is disposed in the substrate and has a first doped region and a second doped region, and the first doped region and the second doped region both include the first conductive type and separatelydisposed under the first isolating structure.

Description

High-voltage semiconductor device

The present invention relates to a semiconductor device, and more particularly to a high-voltage semiconductor device.

With the improvement of semiconductor technology, the industry has been able to integrate control circuits, memory, low-voltage operating circuits, and high-voltage operating circuits and related components on a single chip at the same time to reduce costs and improve operating efficiency. Transistor elements, which are often used to amplify current or voltage signals in circuits, as circuit oscillators, or as switching elements that control circuit switching operations, have been used as high-power elements or high-voltage components with the advancement of semiconductor process technology. element. For example, the transistor element, which is a high voltage element, is placed between the internal circuit of the chip and the input/output (I/O) pins to prevent a large amount of charge from passing through the I/O pins in a very short time. Enter the internal circuit and cause damage.

For a long time, the two main characteristics pursued by high-voltage semiconductor devices are low on-resistance and high breakdown voltage, and these two requirements often conflict with each other and are difficult to weigh. In addition, when the device is operated at a high voltage, the current discontinuity or abnormal increase will also affect the overall performance of the high-voltage semiconductor device. Therefore, how to further improve the electrical performance of the high-voltage semiconductor device is still facing the industry. Subject.

An object of the present invention is to provide a high-voltage semiconductor device, which is additionally provided with an isolated doped region and/or drain doped region, so as to increase the impedance of the high-voltage semiconductor device and improve the uniformity of the electric field , And then obtain better component reliability.

To achieve the above objective, a preferred embodiment of the present invention provides a high-voltage semiconductor device, which includes a substrate, a first insulating structure, a gate, a drain region, a source region, and an isolation doped region. The substrate has a first conductivity type. The first insulating structure is disposed on the substrate. The drain region is disposed in the substrate and has a second conductivity type, and the second conductivity type is complementary to the first conductivity type. The source region is disposed in the substrate. The source region includes a first portion and a second portion, and the first portion has the second conductivity type, and the second portion has the first conductivity type. The gate is disposed on the substrate, located between the source region and the drain region, and partially covers one side of the first insulating structure. The isolation doped region is disposed in the substrate, the isolation doped region includes a first doped part and a second doped part, the first doped part and the second doped part have the first conductivity type And are separately arranged below the first insulating structure.

In order to enable those who are familiar with the technical field of the present invention to have a better understanding of the present invention, a few preferred embodiments of the present invention are listed below, together with the accompanying drawings, to explain in detail the content of the present invention and what it intends to achieve. The effect.

In the present invention, the description of "the first part is formed on or above the second part" can mean "the first part is in direct contact with the second part", or it can mean "between the first part and the second part" There are other parts", so that the first part and the second part are not in direct contact. In addition, various embodiments of the present invention may use repeated component symbols and/or text annotations. The use of these repeated component symbols and text notes is to make the description more concise and clear, rather than to indicate the association between different embodiments and/or configurations. In addition, for the space-related narrative words mentioned in the present invention, for example: "below", "above", "low", "high", "below", "above" "", "below", "above", "bottom", "top" and similar words, for ease of description, their usage is to describe one component or feature and another (or more) components or The relative relationship of features. In addition to the swing outward shown in the diagram, these spatially related words are also used to describe the possible swing directions of the semiconductor device during the manufacturing process, in use, and operation. For example, when the semiconductor device is rotated by 180 degrees, a component that was originally placed "above" other components will become "below" other components. Therefore, as the swing direction of the semiconductor device changes (rotated by 90 degrees or other angles), the space-related narrative used to describe its swing direction should also be interpreted in a corresponding way.

Although the present invention uses terms such as first, second, and third to describe various elements, components, regions, layers, and/or sections, it should be understood that these elements, components, regions, layers, and / Or the block should not be restricted by these words. These terms are only used to distinguish a certain element, component, region, layer, and/or block from another element, component, region, layer, and/or block, and they do not mean or represent the element. Any previous ordinal number does not represent the order of arrangement of a component and another component, or the order of manufacturing methods. Therefore, without departing from the scope of the specific embodiments of the present invention, the first element, component, region, layer, or block discussed below may also be termed as the second element, component, region, layer, or block Of.

The term "about" or "substantially" mentioned in the present invention usually means within 20% of a given value or range, preferably within 10%, and more preferably within 5%, or Within 3%, or within 2%, or within 1%, or within 0.5%. It should be noted that the quantity provided in the manual is approximate, that is, the meaning of "approximate" or "substantial" can still be implied when there is no specific description of "approximate" or "substantial".

Please refer to FIG. 1 and FIG. 2, which show a schematic diagram of the high-voltage semiconductor device 100 in the first embodiment of the present invention. FIG. 1 is a schematic top view of the high-voltage semiconductor device 100, and FIG. 2 is a high-voltage semiconductor device. A schematic cross-sectional view of the semiconductor device 100. The high-voltage semiconductor device of the present invention refers to a semiconductor device with an operating voltage higher than about 90 volts (V), which is, for example, a lateral diffused metal oxide semiconductor transistor (LDMOS transistor), which may be a laterally diffused metal oxide semiconductor transistor (LDMOS transistor). Type metal oxide semiconductor transistor or laterally diffused P-type metal oxide semiconductor transistor. In this embodiment, the high-voltage semiconductor device 100 is described with a laterally diffused N-type metal oxide semiconductor transistor as an implementation mode, but not This is limited.

First, as shown in FIGS. 1 and 2, the high-voltage semiconductor device 100 includes a substrate 110, such as a silicon substrate, an epitaxial silicon substrate, a silicon germanium substrate, a silicon carbide substrate or a silicon-on-insulator (silicon-on-insulator, SOI) substrate, etc., and at least one insulating structure 220 disposed on the substrate 110. The insulating structure 220 is, for example, a field oxide (FOX) layer formed by a local oxidation of silicon (LOCOS) method, such as As shown in Figure 2, but not limited to this. In another embodiment, the insulating structure can also be a shallow trench isolation (STI) formed by a deposition process or an insulating unit manufactured by other suitable processes. It should be noted that, in order to clearly show the relative relationship of certain specific doped regions in the high-voltage semiconductor device 100, the insulating structure 220 is omitted in the first figure, but those familiar with the art should be able to easily understand the insulating structure according to the second figure. The location of the structure 220. In addition, the specific location and quantity of the insulating structure 220 of the present invention will be described in subsequent paragraphs.

The substrate 110 has a first conductivity type (for example, P-type), and a first high-pressure well area 130 and a second high-pressure well area 140 are respectively disposed therein. The first high-voltage well region 130 has a second conductivity type (such as N-type), and the second conductivity type (such as N-type) is complementary to the first conductivity type (such as P-type). A drift region (such as an N-type drift region, not shown) is formed in the region 130, and the drain region 170 of this embodiment is disposed in the drift region and also has the second conductivity type (such as N-type) . The second high-pressure well area 140 is arranged around the outside of the first high-pressure well area 130 and has the first conductivity type (such as P-type). In addition, the substrate 110 is also provided with a buried layer 120, which is located in the substrate 110 below the first high-voltage well region 130. The buried layer 120 may have the second conductivity type (such as N-type), and the buried layer 120 The doping concentration may be higher than the doping concentration of the first high-pressure well region 130. For example, the doping concentration of the buried layer 120 and the first high-pressure well region 130 is, for example, about 1E17-1E18 per cubic centimeter. The doping concentration of the layer 120 is, for example, about 1E18 per cubic centimeter, and the doping concentration of the first high-pressure well region 130 is, for example, about 2E17 per cubic centimeter, but it is not limited to this. Those skilled in the art can follow actual needs. Make adjustments.

The high-voltage semiconductor device 100 further includes a first deep-well region 150 and a second deep-well region 160, which are formed in the first high-pressure well region 130 and the second high-voltage well region 140, respectively, and have the first conductivity type (such as P-type). A source region 190 is formed in the first deep well region 150, and a body region 180 is formed in the second deep well region 160. The doping concentration of the body region 180 is preferably greater than that of the second deep well region 160. Doping concentration. In this embodiment, the source region 190 includes a first portion 191 and a second portion 193 spaced apart from each other. The first portion 191 has the second conductivity type (such as N-type), and the second portion 193 has the second conductivity type. One conductivity type (such as P type). In one embodiment, the first part 191 may be ring-shaped, for example, has a rectangular frame shape (as shown in FIG. 1), and may surround the periphery of the second part 193 without directly contacting the second part 193 , As shown in Figure 1. On the other hand, the base region 180 has the first conductivity type (such as P-type), and preferably does not directly contact the drain region 170 provided in the first high-voltage well region 130. In one embodiment, two opposite sides of the base region 180 are provided with an insulating structure 221 and an insulating structure 223, and two opposite sides of the drain region 170 are provided with an insulating structure 221 and an insulating structure 225, respectively. In this way, the insulating structure 221 is sufficient. It is sandwiched between the drain region 170 and the base region 180 so that the drain region 170 and the base region 180 are electrically isolated from each other, as shown in FIG. 2.

In addition, a gate 210 is also provided on the substrate 110, such as a polysilicon gate or a metal gate. The gate 210 is located between the source region 190 and the drain region 170, so that the gate 210, the source region 190, and the drain region 170 can be electrically connected to corresponding voltage terminals, respectively. In one embodiment, the gate 210 may also have a ring shape, such as a rectangular frame shape, and surround the source region 190, wherein one side of the gate 210 partially covers the first deep well region 150 in the substrate 110 and Adjacent to the first portion 191 of the source region 190, the other side partially covers the insulating structure 225 without directly contacting the drain region 170.

The high-voltage semiconductor device 100 of this embodiment further includes an isolation doped region 230 disposed in the substrate 110 and located under the insulating structure 225. The isolation doped region 230 has the first conductivity type (such as P-type), and it can be located between the drain region 170 and the source region 190 and surround the source region 190, as shown in FIG. 1. Among them, the drain region 170, the source region 190, and the isolation doped region 230 are arranged separately from each other, and the first deep well region 150 and the first high-voltage well region 130 are used to electrically isolate the drain region 170, the source region 190 and the isolation Doped region 230. In an embodiment, the doping concentration of the isolation doped region 230 is, for example, greater than the doping concentration of the first high-pressure well region 130, and the doping concentration of the first deep well region 150 is greater than that of the first high-pressure well region 130. . The doping concentration of the isolation doped region 230 and the first high-voltage well region 130 is, for example, about 1E17-1E18 per cubic centimeter, and the doping depth d of the isolation doped region 230 is, for example, about 0.1 to 2 micrometers (μm). Not limited to this. The doping concentration of the first deep well region 150 is, for example, about 1E18-1E19 per cubic centimeter, but the present invention is not limited to this, and those skilled in the art can make adjustments according to actual needs.

It should be particularly noted that although in this embodiment, the elements surrounding the second portion 193 of the source region 190, such as the first portion 191 of the source region 190, the gate 210, the isolation doped region 230, and the drain The pole region 170, the base region 180, the insulating structure 220, and the second high-voltage well region 140, etc. may all have a rectangular frame shape (as shown in FIG. 1), but the present invention is not limited thereto. The above-mentioned elements may also have other shapes, such as square, circular ring, racetrack-shaped or other suitable shapes, and from a top view (not shown), the whole may have a symmetrical structure. That is, the left and right halves or the upper and lower halves can be symmetrical to each other.

Therefore, the high-voltage semiconductor device 100 in the first embodiment of the present invention can increase the impedance of the high-voltage semiconductor device 100 by providing the isolation doped region 230. When a high-voltage signal flows through this path, the voltage drop capability of the high-voltage semiconductor device 100 is increased due to the increase in the impedance of the high-voltage semiconductor device 100, and the output signal becomes a low-voltage signal. At the same time, the location of the isolation doped region 230 can allow the high-voltage signal to flow to a deeper path, avoiding the direct passage of current, which is beneficial to improve the uniformity of the electric field. In this way, the high-voltage semiconductor device 100 of this embodiment can have better component reliability.

Therefore, a person with ordinary knowledge in the art should easily understand that the high-voltage semiconductor device of the present invention may also have other aspects, which are not limited to the foregoing, on the premise of meeting actual product requirements. The following will further describe other embodiments or variations of the high-voltage semiconductor device. In order to simplify the description, the following description mainly focuses on the differences between the embodiments, and the similarities are not repeated. In addition, the same elements in the various embodiments of the present invention are labeled with the same reference numerals to facilitate comparison between the various embodiments.

According to another embodiment of the present invention, a high-voltage semiconductor device is provided to further solve the kink effect generated by the high-voltage semiconductor device during high-voltage operation. Among them, the so-called "kink effect" refers to a discontinuous or abnormal increase in current when a high-voltage semiconductor device is operated at high voltage, which exceeds the load of the high-voltage semiconductor device itself, resulting in an abnormal electrical performance. It will affect the component performance and electrical performance of high-voltage semiconductor devices. Please refer to FIG. 3, which shows a schematic cross-sectional view of a high-voltage semiconductor device 300 in the second embodiment of the present invention. The structure of the high-voltage semiconductor device 300 in this embodiment is substantially the same as that of the high-voltage semiconductor device 100 described in the aforementioned first embodiment, and also includes a substrate 110, a buried layer 120, a first high-pressure well region 130, a second high-pressure well region 140, The first deep well region 150, the second deep well region 160, the drain region 170, the base region 180, the source region 190, the gate 210, the insulating structure 220, etc., and the similarities will not be repeated here. The main difference between this embodiment and the previous embodiment is that the isolation doped region 330 includes a plurality of doped portions separated from each other, for example, further includes the first doped portion 331 and the second doped portion 333 shown in FIG. 3 And the third doped part 335, but not limited to this. Those skilled in the art should easily understand that, in this embodiment, the number and configuration of the isolation doped regions 330 are only examples, and the specific number and configuration can be further adjusted according to actual device requirements.

Specifically, the first doped portion 331, the second doped portion 333, and the third doped portion 335 of the isolation doped region 330 are also disposed under the insulating structure 225 and can directly contact the insulating structure 225, and have the One conductivity type (such as P type). In an embodiment, the third doped portion 335, the second doped portion 333, and the first doped portion 331 may respectively present a ring shape in a top view (not shown), such as a rectangular frame shape, and may be The sequence surrounds the periphery of the source region 190, so that the first doped portion 331 can surround the second doped portion 333, the third doped portion 335, and the source region 190, and the second doped portion 333 can surround the third doped portion Portion 335 and source region 190. In addition, the isolation doped region 330 is located between the drain region 170 and the source region 190. In an embodiment, the first doped portion 331, the second doped portion 333, and the third doped portion 335 are arranged at equal intervals, for example, the interval g therebetween may all be about 0.1 to 3 microns, but Not limited to this. In another embodiment, it is also possible to choose unequal intervals between the first doped part and the second doped part, and between the second doped part and the third doped part, such as respectively There are intervals of different sizes (not shown). On the other hand, the first doped portion 331, the second doped portion 333, and the third doped portion 335 can optionally have the same doping concentration, for example, about 1E17-1E18 per cubic centimeter, and have The same doping depth d2, such as about 1 to 10 microns, enables the first doped portion 331, the second doped portion 333, and the third doped portion 335 to be formed through the same mask and doping process. But not limited to this. In another embodiment, the first doped portion, the second doped portion, and the third doped portion can also be formed through different masks and doping processes, so that the first doped portion, The second doped part and the third doped part may have different doping concentrations and/or different doping depths (not shown), for example, the first doped part and the second doped part The third doped part and the third doped part respectively have sequentially increasing or decreasing doping concentration and/or doping depth, but not limited to this. With this configuration, the isolation doped region 330 of this embodiment can not only be used to increase the impedance of the high-voltage semiconductor device 300, but the first doped portion 331, the second doped portion 333, and the third doped portion 335 are discontinuous. The structure can generate segmented impedance. In this way, when the high-voltage signal sequentially passes through the first doped portion 331, the second doped portion 333, and the third doped portion 335, the segmented impedance can cause the passing current to be segmented and discontinuous. The reforming of the current in turn makes the electric field more uniform. Please refer to FIG. 4, which shows a schematic diagram of the results of the transmission line pulse test of the high-voltage semiconductor device 100 in the first embodiment of the present invention and the high-voltage semiconductor device 300 in this embodiment. As shown in FIG. 4, a curve A depicts a high-voltage semiconductor device 100 based on the drain terminal of the current (I _D) / linear relationship between the voltage (V _D), the curve B depicts the high-voltage semiconductor device 300 to the drain terminal of the current / voltage Linear relationship, it can be seen that the high-voltage semiconductor device 300 in this embodiment can indeed improve the kink effect and avoid the problem of sudden current increase or discontinuity during high-voltage operation, so that the high-voltage semiconductor device 300 can have better component reliability. .

In addition, the high-voltage semiconductor device 300 may further include a drain doped region 370 disposed in the first high-voltage well region 130 and having the second conductivity type (such as N-type). The drain doped region 370 is, for example, located below the drain region 170 and in the first high-voltage well region 130, and its doping concentration is preferably less than the doping concentration of the drain region 170, the drain doped region 370 The doping concentration of is, for example, about 1E17-1E18 per cubic centimeter, and the doping depth d1 of the drain doped region 370 is, for example, about 0.5 to 1.5 microns, but it is not limited thereto. In this configuration, the impedance of the high-voltage semiconductor device 300 can be increased by the drain doped region 370 to improve its voltage drop capability.

In summary, the high-voltage semiconductor device 300 of the present embodiment further increases the impedance of the high-voltage semiconductor device 300 through the isolation structure of the doped region 330 and/or the additional drain doped region 370, while improving the uniformity of the electric field. Due to the characteristics, the high-voltage semiconductor device 300 can have better component reliability and avoid the kink effect. The foregoing descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the present invention.

100: High-voltage semiconductor device 110: Base 120: Buried layer 130: The first high-pressure well area 140: The second high-pressure well area 150: The first deep well area 160: The second deep well area 170: Drain area 180: base area 190: Source area 191: Part One 193: Part Two 210: Gate 220, 221, 223, 225: insulation structure 230: isolation doped area 300: High-voltage semiconductor device 330: Isolated doped area 331: The first doped part 333: The second doped part 335: The third doped part 370: Drain doped region d, d1, d2: depth g: spacing

Figures 1 to 2 show schematic diagrams of the high-voltage semiconductor device in the first embodiment of the present invention, in which: Figure 1 is a schematic top view of a high-voltage semiconductor device; and Figure 2 is a schematic cross-sectional view of Figure 1 along the line A-A'. FIG. 3 is a schematic cross-sectional view of the high-voltage semiconductor device in the second embodiment of the present invention. FIG. 4 is a schematic diagram showing the results of the transmission-line pulse test (TLP test) of the high-voltage semiconductor device of the present invention.

110: Base 120: Buried layer 130: The first high-pressure well area 140: The second high-pressure well area 150: The first deep well area 160: The second deep well area 170: Drain area 180: base area 190: Source area 191: Part One 193: Part Two 210: Gate 220, 221, 223, 225: insulation structure 300: High-voltage semiconductor device 330: Isolated doped area 331: The first doped part 333: The second doped part 335: The third doped part 370: Drain doped region d1, d2: depth g: interval

Claims (15)

A high-voltage semiconductor device, including: A substrate having a first conductivity type; A first insulating structure arranged on the substrate; A drain region disposed in the substrate, the drain region has a second conductivity type, and the second conductivity type is complementary to the first conductivity type; A source region disposed in the substrate, the source region includes a first part and a second part, the first part has the second conductivity type, and the second part has the first conductivity type; A gate disposed on the substrate, located between the source region and the drain region and partially covering one side of the first insulating structure; and An isolation doped region is disposed in the substrate. The isolation doped region includes a first doped part and a second doped part. The first doped part and the second doped part have the first conductive Type and spaced apart from each other arranged under the first insulating structure. A high-voltage semiconductor device as described in item 1 of the scope of patent application, further includes: A drain doped region is disposed in the substrate, wherein the dopant concentration of the drain region is greater than the dopant concentration of the drain doped region. The high-voltage semiconductor device described in claim 1, wherein the first part and the second part are spaced apart from each other and the first part surrounds the second part. The high-voltage semiconductor device described in item 1 of the scope of the patent application further includes a deep well region disposed in the substrate and the deep well region has the first conductivity type, and the source region is disposed in the deep well region. For the high-voltage semiconductor device described in item 4 of the scope of patent application, the gate electrode partially covers the deep well area. The high-voltage semiconductor device described in item 4 of the scope of patent application further includes a first high-voltage well region disposed in the substrate and the first high-voltage well region has the second conductivity type. According to the high-voltage semiconductor device described in claim 6, wherein the drain region, the deep well region and the isolation doped region are all disposed in the first high-voltage well region. The high-voltage semiconductor device described in item 6 of the scope of the patent application further includes a second high-voltage well region disposed in the substrate and the second high-voltage well region has the first conductivity type and surrounds the first high-voltage well region. The high-voltage semiconductor device described in item 8 of the scope of patent application further includes a base region located in the second high-voltage well region. The high-voltage semiconductor device described in item 9 of the scope of patent application further includes a second insulating structure disposed on the substrate and located between the base region and the drain region. The high-voltage semiconductor device described in item 6 of the scope of the patent application further includes a buried layer disposed in the substrate, and the buried layer has the second conductivity type and is located below the first high-voltage well region. According to the high-voltage semiconductor device described in claim 1, wherein the first doped portion and the second doped portion have the same doping concentration and depth. The high-voltage semiconductor device described in claim 1, wherein the first doped part surrounds the second doped part. According to the high-voltage semiconductor device described in claim 1, wherein the first insulating structure surrounds the source region. The high-voltage semiconductor device according to claim 1, wherein the side of the first insulating structure is adjacent to the source structure.

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