This application claims the benefit under 35 U.S.C. § 119(a) of Chinese Patent Application No. 202211581689.2 filed Dec. 9, 2022, the contents of which are incorporated by reference herein in their entirety.
The present disclosure is related to the field of semiconductor technology, and particularly to a semiconductor device including a gate busbar.
A power semiconductor device, such as an Insulated Gate Bipolar Transistor (IGBT), includes a plurality of cells connected in parallel. An IGBT has three electrodes being gate, emitter and collector. The emitter and the gate are located on the front side of the chip, while the collector is located on the backside of the chip. Gate signals from an external circuit are applied to the gate pad and then transmitted to the gates of the respective cells through the gate busbar, thereby controlling the turn-on of each cell.
With the increasing demand of high power and high frequency applications in the field of power semiconductor devices, sizes of the power chips become bigger and bigger, and a power chip contains more and more cells connected in parallel. The parasitic parameters of the gate busbar could not be ignored, which increases the delay of the gate signals received by the cells away from the gate pad, and further results in uneven current distribution, especially under high frequency applications.
CN114220853A disclosed that current sharing of the cells is realized by designing the width of the annular gate busbar located in the peripheral area of the power chip. Specifically, the farther the annular gate busbar was from the gate pad, the smaller the width of the annular gate busbar became. The solution therein only considered the width of the annular gate busbar located in the peripheral area of the power chip and provides only one width design solution for the annular gate busbar, which has very limited effect in solving the current sharing problem of the cells.
The present disclosure provides a semiconductor device having emitter segments with non-uniform lengths and a gate busbar with non-uniform widths or thicknesses to ensure that each cell could receive a relatively consistent gate signal.
The semiconductor device according to the present disclosure includes a plurality of cells, each of the plurality of cells includes a gate. The semiconductor device includes a gate pad, a gate busbar and a plurality of gate lines, the gate busbar connects the gate pad to the plurality of gate lines, the plurality of gate lines connects the gate busbar to the gates of the plurality of cells, each of the plurality of gate lines is disposed along a first axis. The gate busbar includes a plurality of first portions each disposed along a second axis, the second axis intersects with the first axis, the plurality of first portions are spaced apart from each other to divide the semiconductor device into a plurality of emitter segments. Lengths of the plurality of emitter segments along the first axis change with distances of the plurality of emitter segments from the gate pad, such that gate signals arriving at the gates of the plurality of cells from the gate pad via the gate busbar and the plurality of gate lines are consistent.
In an embodiment of the present disclosure, the gate pad is disposed on a first portion of the plurality of first portions along the second axis, the gate busbar further includes a plurality of second portions each disposed along the first axis, the plurality of second portions include a first group of second portions disposed on a first side edge of the semiconductor device and connected in sequence, and a second group of second portions disposed on a second side edge of the semiconductor device and connected in sequence, the plurality of first portions are connected between the first group of second portions and the second group of second portions, and widths or thicknesses of the plurality of first portions are different from each other.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions gradually decrease in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions gradually decrease in the first direction, and lengths of the plurality of emitter segments along the first axis gradually decrease in the first direction.
In an embodiment of the present disclosure, an end of each of the plurality of second portions away from the gate pad is connected to a corresponding one of the plurality of first portions, a width of each of the plurality of second portions is equal to a sum of a width of a first portion connected to an end of the second portion away from the gate pad and a width of another second portion connected to the end of the second portion away from the gate pad.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions gradually increase in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions gradually increase in the first direction, and lengths of the plurality of emitter segments along the first axis gradually increase in the first direction.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions first increase and then decrease in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions first increase and then decrease in the first direction, and lengths of the plurality of emitter segments along the first axis first increase and then decrease in the first direction.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions first decrease and then increase in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions first decrease and then increase in the first direction, and lengths of the plurality of emitter segments along the first axis first decrease and then increase in the first direction.
In an embodiment of the present disclosure, at least one of the plurality of first portions is provided with an opening.
In an embodiment of the present disclosure, each of the plurality of first portions is provided with an opening.
In an embodiment of the present disclosure, the gate pad is located at a corner of the semiconductor device, and the opening is located at a corner opposite to the gate pad.
In an embodiment of the present disclosure, the gate pad is disposed on one first portion of the plurality of first portions along the first axis, the gate busbar further includes a plurality of second portions each disposed along the first axis, and the plurality of second portions connect the first portions of the plurality of first portions to the gate pad except the one first portion, and widths or thicknesses of the plurality of first portions are different from each other.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions gradually decrease in a first direction, the first direction points from the gate pad toward a side away from the gate pad along the first axis, widths or thicknesses of the plurality of second portions gradually decrease in the first direction, and lengths of the plurality of emitter segments along the first axis gradually decrease in the first direction.
In an embodiment of the present disclosure, an end of each of the plurality of second portions away from the gate pad is connected to a corresponding one of the plurality of first portions, a width or thickness of each of the plurality of second portions is equal to a sum of a width of a first portion connected to an end of the second portion away from the gate pad and a width of another second portion connected to the end of the second portion away from the gate pad.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions gradually increase in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions gradually increase in the first direction, and lengths of the plurality of emitter segments along the first axis gradually increase in the first direction.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions first increase and then decrease in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions first increase and then decrease in the first direction, and lengths of the plurality of emitter segments along the first axis first increase and then decrease in the first direction.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first portions first decrease and then increase in a first direction, the first direction parallels to the first axis and points toward a side away from the gate pad, widths or thicknesses of the plurality of second portions first decrease and then increase in the first direction, and lengths of the plurality of emitter segments along the first axis first decrease and then increase in the first direction.
In an embodiment of the present disclosure, the gate pad is disposed along the first axis, the gate busbar further includes a second portion disposed along the first axis, the second portion connects the first portions to the gate pad, each of the plurality of first portions includes a plurality of first sub-portions each disposed along the second axis and connected in sequence, and at least one of widths, thicknesses and lengths of the plurality of first sub-portions change along the second axis.
In an embodiment of the present disclosure, widths or thicknesses of the plurality of first sub-portions change in a second direction, the second direction parallels to the second axis and points toward a side away from the gate pad, and lengths of the plurality of first sub-portions change in the second direction, and the second portion has a uniform width along the first axis.
In an embodiment of the present disclosure, the widths or thicknesses of the plurality of first sub-portions gradually decrease in the second direction, and the lengths of the plurality of first sub-portions along the second axis gradually decrease in the second direction.
In an embodiment of the present disclosure, the widths or thicknesses of the plurality of first sub-portions gradually increase in the second direction, and the lengths of the plurality of first sub-portions along the second axis gradually increase in the second direction.
In an embodiment of the present disclosure, the widths or thicknesses of the plurality of first sub-portions first increase and then decrease in the second direction, and the lengths of the plurality of first sub-portions along the second axis first increase and then decrease in the second direction.
In an embodiment of the present disclosure, the widths or thicknesses of the plurality of first sub-portions first decrease and then increase in the second direction, and the lengths of the plurality of first sub-portions along the second axis first decrease and then increase in the second direction.
In an embodiment of the present disclosure, the gate pad is located in a middle region of the semiconductor device, the gate busbar further includes a third portion connected to ends of adjacent first portions at an edge of the semiconductor device, the third portion is disposed along the first axis, the plurality of emitter segments are defined by the plurality of first portions, the second portion and the third portion, and widths of the plurality of emitter segments along the second axis are different from each other.
In an embodiment of the present disclosure, the gate pad is located at a corner, in the middle of a side edge, or in a middle region of the semiconductor device.
In an embodiment of the present disclosure, the gate busbar further includes a third portion connected to ends of adjacent first portions at an edge of the semiconductor device, and the third portion is disposed along the first axis and is provided with an opening.
In an embodiment of the present disclosure, the plurality of emitter segments are isolated from each other.
In order for a person skilled in the art to better understand the technical solutions of the present disclosure, as non-limiting examples, the semiconductor device provided by the present disclosure will be described in detail below in conjunction with the accompanying drawings.
It should also be noted that for the purpose of describing these exemplary embodiments herein, the views will show general features of the methods and devices of the exemplary embodiments of the present disclosure. These views, however, are not drawn to scale and may not precisely reflect the features of any given embodiment, and should not be understood as defining or limiting the range of values or characteristics of the exemplary embodiments within the scope of the present disclosure.
The terms such as “having”, “including”, “comprising” and “containing” are open-ended, these terms indicate the existence of stated structures, elements or features, but do not preclude the existence of additional elements or features. The articles “a,” “an” or “the” are intended to include both the plural and the singular, except where the context explicitly indicates otherwise.
The present disclosure proposes a semiconductor device having a plurality of cells, and the semiconductor device includes a gate busbar with a novel structure. As known, each cell of the semiconductor device includes a gate, an emitter and a collector. The semiconductor device further includes a gate pad and a plurality of gate lines connected to the gates of the plurality of cells along a first axis. The gate busbar connects the gate pad to the plurality of gate lines. The gate pad receives external gate signals, which are transmitted to the plurality of gate lines via the gate busbar, and then arrive at the gates of the respective cells. The gate busbar includes a plurality of first portions each disposed along a second axis. The plurality of first portions are connected to the plurality of gate lines, such that the arrangement direction of the plurality of first portions (i.e., the first axis) intersects with the arrangement direction of the plurality of gate lines (i.e., the second axis). The plurality of first portions are spaced apart from each other to divide the semiconductor device into a plurality of emitter segments. Lengths of the plurality of emitter segments along the first axis change with distances of the plurality of emitter segments from the gate pad, such that gate signals arriving at the gates of the plurality of cells from the gate pad via the gate busbar and the plurality of gate lines are consistent.
It should be noted that “the element(s) is/are disposed along the axis” described herein means that the length direction of the element(s) is parallel to the axis, the element(s) herein for example may include the gate pad, a part of the gate busbar, or the gate lines, etc., “gate signals arriving at the gates of the plurality of cells are substantially consistent” means that the difference between the gate signals arriving at the gates of the plurality of cells is within a predetermined range. For example, the maximum time for the gate signals to arrive at the respective emitter segments may be the same to ensure that cells in the plurality of emitter segments could be turned on at the same time.
The semiconductor device according to the present disclosure is not only suitable for the trench gate structure, but also suitable for the plane gate structure. In the case of the trench gate structure, the trench gate is disposed along the first axis. In the case of the plane gate structure, the plane gate is disposed along the first axis. The following embodiments are described in the context of the trench gate structure.
Generally, the gate busbar is made of a metal having relatively low resistivity, and the gates of the respective cells are made of polysilicon having relatively high resistivity. In the embodiments of the present disclosure, the material of the gate busbar may include metals and/or alloys such as Al, AlCu, and AlSiCu. In some embodiments, the gate busbar only includes a metal layer. In some embodiments, the gate busbar includes a polysilicon layer and a metal layer.
The semiconductor device of the present disclosure further includes an emitter pad and a collector pad. As an example, the emitter pad and the gate pad may be located on the front side of the semiconductor device, and the collector pad may be located on the backside of the semiconductor device. Other suitable arrangements are also possible to a person skilled in the art.
Further, the semiconductor device further includes a substrate. The cells, the gate pad, the emitter pad, the collector pad, the gate busbar and the gate lines of the semiconductor device are all formed on the substrate. The material of the substrate may be silicon, silicon carbide, gallium nitride or the like, which are not restricted in the present disclosure.
The semiconductor device of the present disclosure may be a power semiconductor device such as an IGBT, a MOSET, a BJT, an MCT, particularly suitable for large current chips. The power semiconductor device according to the present disclosure may be applied to the fields of electric vehicles, hybrid electric vehicles, on-board chargers, solar energy, welding, uninterruptible power supply, power factor correction, storage devices, and so on.
In
It should be noted that, widths and lengths of the first portions/the second portions respectively refer to widths and lengths of the first portions/the second portions in the surface (i.e. the front side) of the semiconductor device, and thicknesses of the first portions/the second portions refer to sizes of the first portions/the second portions in a thickness direction of the semiconductor device. It could be understood that for a liner element, its length is the size in its extension direction, its width is the size in a direction perpendicular to its extension direction, and the length is greater than the width. For example, in
In the embodiments of the present disclosure, the lengths of the emitter segments along the first axis and the width/thickness of the gate busbar are designed to ensure that each cell could receive a substantially consistent gate signal. The gate signal difference between the respective cells could be reduced, no matter how far the cells are from the gate pad, which improves the current sharing capability of the chip.
As shown in
In an embodiment of the present disclosure, as shown in
In an embodiment of the present disclosure, an end of each of the second portions 122 away from the gate pad 11 is connected to a corresponding one of the first portions 121, and a width of each of the second portions 122 is equal to a sum of a width of a first portion 121 connected to an end of the second portion 122 away from the gate pad 11 and a width of another second portion 122 connected to the end of the second portion 122 away from the gate pad 11.
The implementation of the semiconductor device shown in
when i=1, vγ1=Vβ0+Vα1+Vβ1+VA1, and
when i>1, Vβ(i-1)+vγi=Vαi+Vβi+Vλi,
Where V denotes the voltage of the gate busbar, while v denotes the voltage of the trench gates. Specifically, Vαi denotes the voltage of the ith second portion in the first direction, Vαi denotes the voltage of the first portion (i.e., the ith first portion) connected to an end of the ith second portion away from the gate pad, Vλi denotes the voltage of the trench gate from the ith first portion to the gate between the ith first portion and the (i−1)th first portion, and vγi denotes the voltage of the trench gates from the (i−1)th first portion to the gate between the (i−1)th first portion and the ith first portion.
In the equivalent circuit diagram of
Voltage of the trench gate: Vλi=Vγ(i+1),
Length: Lλi=Lγ(i+1),Lγi+Lλi=Lαi,ΣLαi=1,Lβi=w/2,
Gate busbar current: Iαi=Iα(i+1)+Iβi,
Trench gate current: iλi=iγ(i+1)=Iβi/2/((w/2)/pitch);
Width: Wαi=Wα(i+1)+Wβi.
Under the above conditions, if the design conditions I>Lαi>Lα(i+1)>=0, Wβi>Wβ(i+1) are satisfied, the following results could be obtained:
taking three emitter segments (x=3) as an example, if Wβ3>=5 μm, Lλx=(0˜I/x/2), the following could be obtained:
L
α1=(0.3˜1)*I,Lα2=(0˜0.4)*I,Lα3=(0˜0.3)*I,
W
α1=(3˜15)*Wβ3,Wα2=(2˜8)*Wβ3,Wα3=Wβ3,
W
β0=(3˜15)*Wβ3,Wβ1=(1˜10)*Wβ3,Wβ2=(1˜7)*Wβ3.
It could be understood that the resistance of the gate busbar (including the first portions and the second portions) may be adjusted by one of the width and thickness, and the length of the gate busbar, thereby reducing gate signal difference between the respective cells. For example, the gate busbar as a whole may have a constant width, but its thickness changes with distance of the gate busbar from the gate pad, and the lengths of the emitter segments along the first axis change with distances of the emitter segments from the gate pad. In this way, gate signal difference between the respective cells could be reduced, and the active region area could be further increased as well.
In an embodiment of the present disclosure, the first portions and second portions of the gate busbar may be formed simultaneously. In this way, no additional process step is needed. In the case where the material of the gate busbar is polysilicon and metal, the gate busbar is formed by depositing and etching polysilicon, and depositing and etching the front metal. In the case where the material of the gate busbar is metal only, the gate busbar is formed by depositing and etching the front metal.
In
The cases where widths or thicknesses of the plurality of first portions, widths or thicknesses of the plurality of second portions, and lengths of the plurality of emitter segments along the first axis all change in the first direction are described above, but it could be understood that the present disclosure is not limited thereto. At least one of widths or thicknesses of the plurality of first portions, widths or thicknesses of the plurality of second portions, and lengths of the plurality of emitter segments along the first axis may be reasonably designed as long as the gate signals arriving at the gates of the plurality of cells are substantially consistent.
Furthermore, the number of the first portions of the gate busbar is not particularly limited in the present disclosure, and may be reasonably set according to actual needs.
In
Within each of the emitter segments, emitters of the respective cells of the semiconductor device are disposed. The interconnection relationship between the emitters within different emitter segments is not particularly limited in the present disclosure. For example, emitters in adjacent emitter segments may be physically connected to each other such that the potentials of the respective emitter segments are substantially the same. The emitters are partially or fully connected, so that subsequent routing is simple. As shown in
In some embodiments, an opening may be provided on each of the first portions of the gate busbar.
In the present disclosure, lengths and positions of the openings on the first portions of the gate busbar may be set according to actual needs. For example, as shown in
In
In
In the embodiments of the present disclosure, lengths of the emitter segments along the first axis and the width/thickness of the gate busbar (including the first portions and the second portions) are designed to ensure that each cell could receive a substantially consistent gate signal. The gate signal difference between the respective cells could be reduced, no matter how far the cells are from the gate pad, which improves the current sharing capability of the chip.
As shown in
In an embodiment of the present disclosure, in a direction from the gate pad 11 to a side away from the gate pad 11 along the first axis A1 (i.e., in a first direction pointing from the gate pad 11 toward a side away from the gate pad 11 along the first axis A1), widths or thicknesses of the plurality of first portions 121 gradually decrease, widths or thicknesses of the plurality of second portions 122 gradually decrease, and lengths of the plurality of emitter segments 14 along the first axis A1 gradually decrease. In
In an embodiment of the present disclosure, an end of each of the second portions 122 away from the gate pad 11 is connected to a corresponding one of the first portions 121, a width of each of the second portions 122 is equal to a sum of a width of a first portion 121 connected to an end of the second portion 122 away from the gate pad 11 and a width of another second portion 122 connected to the end of the second portion 122 away from the gate pad 11. As shown in
The implementation of the semiconductor device shown in
V
βi
+V
γ(i+1)
=V
α(i+1)
+V
β(i+1)
+v
λ(i+1),
Where V denotes the voltage of the gate busbar while v denotes the voltage of the trench gate. Specifically, Vα(i+1) denotes the voltage of the (i+1)th second portion in the first direction, Vαi denotes the voltage of the first portion (i.e., the ith first portion) connected to an end of the ith second portion away from the gate pad, Vγ(+1) denotes the voltage of the trench gate from the ith first portion to the gate between the ith first portion and the (i+1)th first portion, and Vλ(i+1) denotes the voltage of the trench gate from the (i+1)th first portion to the gate between the ith first portion and the (i+1)th first portion.
In the equivalent circuit diagram of
voltage of the trench gate: vλi=vγ(i+1).
length: Lλi=Lγ(i+1),Lyi+Lλi=Lαi,ΣLαi=w/2,Lβi=I,
gate busbar current: Iαi=Iα(i+1)+Iβi,
trench gate current: iλi=iγ(i+1)=Iβi/2/(I/pitch),
width: Wαi=Wα(i+1)+Wβi,
Under the above conditions, if the design conditions w/2>Lαi>Lα(i+1)>=0, Wβi>Wβ(i+1) are satisfied, the following results could be obtained:
taking two emitter segments (x=2) as an example, if Wβ2>=5 μm, the following could be obtained:
W
β0=(1˜15)*Wβ2,Wβ1=(1˜15)*Wβ2,
L
α1=[(1/x)˜1]*w/2,Lα2=[0˜(1/x)]*w/2,
W
α1=(2˜16)*Wβ2,Wα2=Wβ2.
In
As described above, the present disclosure is also not limited to the cases where widths or thicknesses of the plurality of first portions, widths or thicknesses of the plurality of second portions, and lengths of the plurality of emitter segments along the first axis all change in the first direction. At least one of widths or thicknesses of the plurality of first portions, widths or thicknesses of the plurality of second portions, and lengths of the plurality of emitter segments along the first axis may be reasonably designed as long as gate signals arriving at the gates of the plurality of cells are substantially consistent.
In an embodiment of the present disclosure, as shown in
In the embodiments of the present disclosure, lengths of the emitter segments along the first axis and the width/thickness of each of the first portions of the gate busbar are designed to ensure that each cell could receive a substantially consistent gate signal. The gate signal difference between the respective cells could be reduced, no matter how far the cells are from the gate pad, which improves the current sharing capability of the chip.
As shown in
In an embodiment of the present disclosure, in a second direction parallel to the second axis and pointing toward a side away from the gate pad 11, widths or thicknesses of the plurality of first sub-portions 1211 gradually change and differ from each other, and lengths of the plurality of first sub-portions 1211 gradually change and differ from each other. In
The implementation of the semiconductor device shown in
Σi=1xVαi+vβx=V0+Σi=1xVαi+vγx,
Where V denotes the voltage of the gate busbar while v denotes the voltage of the trench gate. Specifically, Vαi denotes the voltage of the ith first sub-portion in the second direction, V0 denotes the voltage of the second sub-portion between adjacent first sub-portions, and vβx and vγx denote the voltages of the trench gates from two adjacent first sub-portions to the gate therebetween, respectively.
In the equivalent circuit diagram of
voltage: vβi=Vα(i+1)+vβ(i+1).
length: ΣLαi=l,Lγi+Lβi=w/2,
current: Iαi=Iα(i+1)+iβi*2*Lαi/pitch,Iαi=Iα(i+1)+iγi*Lαi/pitch.
Under the above conditions, if the design conditions I>Lαi>Lα(i+1)>=0, Wβi>Wβ(i+1) are satisfied, the following results could be obtained:
taking three first sub-portions (x=3) as an example, if Wα3>=5 μm, Lβi=(0.5˜1)*(w/2)), the following could be obtained:
L
α1=(0.3˜0.7)*I,Lα2=(0.2˜0.5)*I,Lα3=(0˜0.3)*I;
W
α1=(1˜15)*Wα3,Wα2=(1˜8)*Wα3
In
In the embodiments of the present disclosure, at least one of widths or thicknesses of the plurality of first sub-portions, lengths of the plurality of first sub-portions, and lengths of the plurality of emitter segments along the first axis may be reasonably designed so that gate signals arriving at the gates of the plurality of cells are substantially consistent.
As shown in
In an embodiment of the present disclosure, as shown in
It could be understood that the gate pad 11 may be disposed in connection with and in contact with only the second portion 122, instead of the first portions 121, as shown in
Within a same emitter segment, the emitters may be physically interconnected, as shown in
Finally, it should be noted that the above embodiments are only used to illustrate, rather than limit, the technical solutions of the present disclosure. Although the present disclosure has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that: the technical solutions recited in the above embodiments could be modified, or some or all of the technical features thereof could have equivalent substitutions, for example, the features of the dependent claims could be freely replaced and/or combined as required, and these modifications or substitutions do not essentially make the corresponding technical solutions depart from the scope of the technical solutions of the embodiments in the present disclosure.
Number | Date | Country | Kind |
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202211581689.2 | Dec 2022 | CN | national |