TWI577014B - Heterojunction bipolar transistor - Google Patents

Description

Heterojunction bipolar transistor

The present invention relates to a heterojunction bipolar transistor, and more particularly to a heterojunction bipolar transistor having a higher emitter to base area ratio to improve transistor power gain.

In recent years, with the booming mobile device industry, there is an increasing demand for high power, high power gain, and high power gain efficiency. Due to the advantages of high power, high power gain, and high linearity of the compound semiconductor heterojunction bipolar electro-crystal volume circuit, it is often used to fabricate components such as power amplifiers in mobile devices. Therefore, if the compound semiconductor heterojunction can be improved The bipolar transistor layout will effectively improve power gain and power gain efficiency and enhance product competitiveness.

The output power gain of a heterojunction bipolar transistor is related to the base and collector indirect plane capacitance of the transistor. The junction capacitance is proportional to the base area. The larger the emitter-to-base area ratio (EA/BA) is, the smaller the base and collector indirect surface capacitance is. Therefore, the emitter-to-base area ratio is increased, and the collector capacitance can be effectively reduced. In turn, the output power gain is increased.

The main object of the present invention is to provide a heterojunction bipolar transistor having the following characteristics: 1. having a higher emitter to base area ratio (EA/BA) to enhance the heterojunction bipolar transistor. Power gain; 2. Has a smaller collector resistance to provide power gain efficiency of a heterojunction bipolar transistor Rate; 3. Has a better emitter current distribution to enhance the high power operation capability of the heterojunction bipolar transistor.

To achieve the above object, the present invention provides a heterojunction bipolar transistor comprising: an elongated base platform, an elongated base electrode, two elongated emitters, and a long strip collector And two long strip-shaped collector electrodes, wherein the long strip-shaped base electrode is disposed on the base platform along the long axis of the base platform, and at or near the center of the base electrode a base via hole is disposed at the center; the two elongated strip emitters are respectively located on the base platform and the two sides of the base electrode, and each of the foregoing emitter regions is disposed above a strip-shaped emitter electrode; the collector is located below the base platform; and the two strip-shaped collector electrodes are respectively located above the collector and opposite sides of the base platform .

The present invention also provides another heterojunction bipolar transistor comprising: an elongated base platform, an I-shaped emitter, two base electrodes, a long strip collector, and two long strip sets a pole electrode, wherein the aforementioned I-shaped emitter is located on the base platform, and a recess is respectively disposed on two sides of the I-shape, and two elongated emitters are disposed on the I-shaped emitter region The electrodes are respectively disposed on the base platform and the recesses on both sides of the I-shaped emitter, and each base electrode is provided with a base guide at one end of the base plate adjacent to the center of the base platform. a hole; the foregoing collector is located under the base platform; and the two elongated collector electrodes are respectively located above the collector and opposite sides of the aforementioned base platform.

In the implementation, the base electrode is disposed on the base platform, at the center of the short axis of the base platform or adjacent to the center along the long axis of the base platform.

In implementation, the aforementioned elongated base platform has an aspect ratio ranging from 1.2:1 to 15:1.

In the implementation, the base platform, the emitter electrode and the collector electrode are all rectangular.

In implementation, the recessed portion of the aforementioned I-shaped emitter is disposed at or near the center of the short axis of the aforementioned base platform.

In implementation, the aforementioned base platform, emitter, and collector are bent elongated strips that are located at or near the center of the elongated strip.

In the implementation, the aforementioned base platform, the emitter and the collector are bent long strips, and the bends are located at or near the center of the elongated strip, and the angle of the bend is 90°.

For a better understanding of the features and functions of the present invention, the embodiments are described in detail below with reference to the drawings.

100, 200, 300‧‧‧ Heterojunction Bipolar Transistor

110, 210, 310‧‧‧ base platform

111, 211a, 211b, 311‧‧‧ base electrode

112, 212a, 212b, 312‧‧‧ base guide hole

120a, 120b, 220, 320a, 320b‧‧ ‧ emitter

121a, 121b, 221, 321a, 321b‧‧‧ emitter electrodes

130, 230, 330‧‧ ‧ collector

131a, 131b, 231a, 231b, 331‧‧ ‧ collector electrodes

140a~140e, 240a~240d‧‧‧Metal wire of the first metal layer

150, 250‧‧‧Metal wire of the second metal layer

1A and 1B are top plan views of an embodiment of a heterojunction bipolar transistor provided by the present invention.

2A and 2B are schematic cross-sectional views of an embodiment of a heterojunction bipolar transistor according to the present invention taken along lines A-A' and B-B', respectively.

3A and 3B are top plan views of another embodiment of a heterojunction bipolar transistor provided by the present invention.

Figures 4, 5 and 6 are top plan views of other embodiments of a heterojunction bipolar transistor provided by the present invention.

1A, 1B, 2A and 2B are an embodiment of a type I heterojunction bipolar transistor 100 provided by the present invention, comprising: a rectangular base platform 110 and a rectangular base electrode 111. Two rectangular emitters 120a, 120b, one elongated collector 130 and two rectangular collector electrodes 131a, 131b, wherein the rectangular base electrode 111 is flat along the base The long axis Y of the stage 110 is disposed on the base platform 110, and a base via hole 112 is disposed at or near the center of the base electrode 111; the two rectangular emitters 120a, 120b are respectively located on the base platform 110, on both sides of the base electrode 111, and each of the emitter regions 120a, 120b is provided with a rectangular emitter electrode 121a, 121b; the collector 130 is located below the base platform 110; and two rectangles The collector electrodes 131a and 131b are respectively located above the collector 130 and opposite sides of the base platform 110.

In the implementation, the base electrode 111, the emitter electrode 121, and the collector electrodes 131a and 131b are electrically connected to the metal wires (140a-140e) formed by a first metal layer, and then pass through the first metal. The layer is electrically connected to the metal wire 150 formed by a second metal layer, and is connected to other electronic components by the first or second metal layer to form a desired circuit. The portion of the I-type heterojunction bipolar transistor 100 that is electrically connected to the first metal layer is isolated by one or more protective layers (eg, 160a), and the first metal layer and the second metal layer are not electrically connected. The part is also isolated by at least one protective layer (such as 160b, 160c). The material of the protective layer must be electrically insulating, and it must be prevented from diffusing into the heterojunction bipolar transistor in the metal layer or other structure. In one example, the one to more protective layers may be made of a material having good insulating properties such as tantalum nitride (SiN) or polyimide.

The collector-to-emitter resistance (R _CE ) is related to the length of the collector and the emitter's adjacent perimeter, and the longer the perimeter of the collector and emitter is, the lower the R _{CE is} . In the heterojunction bipolar transistor provided by the present invention, the design of the collector on both sides of the emitter can increase the length of the perimeter of the collector and the emitter, thereby reducing the collector resistance R _CE and providing heterogeneity The power gain efficiency of the junction bipolar transistor. In addition, in the design provided by the present invention, the transistor operates by inputting a signal from the first metal layer through the base via hole to the transistor, and the emitter current is distributed because the base via hole is located at the center of the transistor. Symmetrical or nearly symmetrical, thus improving the high power operation capability of heterojunction bipolar transistors.

In this embodiment, in order to achieve an optimum ratio of the emitter to the base, the aspect ratio of the rectangular base platform may be any value from 1.2:1 to 15:1, for example, 2:1. 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15: 1, preferably 2:1 to 12:1, more preferably 3:1 to 12:1, or even 4:1 to 10:1.

The base, the emitter, the collector, and the base, the emitter, and the collector electrode disposed thereon may be any other elongated shape, such as an elliptical shape, as long as the long axes of the elongated lines are parallel to each other That's it, as shown in Figure 4.

The base, the emitter, the collector, and the base, the emitter, and the collector electrode disposed thereon may be any bent elongated shape, and may have one or more bends, such as the sixth The L-shaped heterojunction bipolar transistor 300 has a bent portion, and the base platform 310, the two emitters 320a, 320b, and the collector 330 are all L-shaped, and the bending angle can be greater than 0° to less than 180°, in the embodiment shown in Fig. 6, the bending angle is about 90°.

3A and 3B are top plan views of an embodiment of an H-type heterojunction bipolar transistor 200 provided by the present invention, comprising: a rectangular base platform 210, an I-beam emitter 220, and two a base electrode 211a, 211b, a rectangular collector 230 and two elongated collector electrodes 231a, 231b, wherein the I-shaped emitter 220 is located on the base platform 210, and a recess is respectively arranged on both sides of the I-shaped The portion 222a, 222b, and the I-shaped emitter region 220 is provided with an I-shaped emitter electrode 221; the base electrodes 211a, 211b are respectively disposed on the base platform 210, the recessed portion 222a on both sides of the I-shaped emitter 220 222b, and each of the base electrodes 211a/211b is provided with a base via 212a/212b at one end of the base of the base platform 210; and the aforementioned rectangular collector 230 is located under the base platform 210. The two strip-shaped collector electrodes 231a and 231b are respectively located above the collector 230 and opposite sides of the base platform 210.

In the implementation, the base electrodes 211a and 211b, the emitter electrode 221 and the collector electrodes 231a and 231b are electrically connected to the metal wires formed by a first metal layer. (240a-240d) is electrically connected to the metal wire 250 formed by a second metal layer through the first metal layer, and the first or second metal layer is connected to other electronic components to form a desired circuit. The portion of the H-type heterojunction bipolar transistor 200 that is electrically connected to the first metal layer is isolated by one or more protective layers, and the portion of the first metal layer and the second metal layer that is not electrically connected is also At least one protective layer is isolated, and the material of the protective layer must be electrically insulated, and at the same time, it is necessary to prevent the material of the metal layer or other structure from diffusing into the heterojunction bipolar transistor. In this embodiment, the one to more protective layers may be It is composed of a material having excellent barrier properties such as tantalum nitride (SiN) or polyimide.

In this embodiment, in order to achieve an optimum ratio of the emitter to the base, the aspect ratio of the rectangular base platform may be any value from 1.2:1 to 15:1, for example, 2:1. 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15: 1, preferably 2:1 to 12:1, more preferably 3:1 to 12:1, or even 4:1 to 10:1.

The base, the emitter, the collector, and the base, the emitter, and the collector electrode disposed thereon may be any other elongated shape, such as an elliptical shape, as long as the long axes of the elongated lines are parallel to each other That's it, as shown in Figure 5.

The invention has the following advantages:

1. The strip-shaped heterojunction bipolar transistor provided by the invention has a high emitter-to-base ratio (EA/BA), which improves the power gain of the heterojunction bipolar transistor.

2. The design of the collector on both sides of the emitter can increase the length of the perimeter of the collector and the emitter, and obtain a longer perimeter by designing the emitter and the collector to form a strip, thus obtaining The relatively low collector-to-emitter resistance R _CE provides the power gain efficiency of the heterojunction bipolar transistor.

3. The distribution of the emitter current is symmetric or nearly symmetrical, thus improving the high power operation capability of the heterojunction bipolar transistor.

In summary, the heterojunction bipolar transistor provided by the present invention can be achieved The intended purpose is to provide a higher emitter-to-base ratio, which increases the power gain of the heterojunction bipolar transistor. In addition, the heterojunction bipolar transistor provided by the invention has a small collector-to-emitter resistance, which can improve the power gain efficiency of the heterojunction bipolar transistor, which is fabricated by the heterojunction bipolar transistor. The main performance appeal of the power amplifier. It does have the value of industrial use, and it submits invention patent applications according to law.

The above description and the drawings are merely illustrative of the embodiments of the present invention, and those skilled in the art can still make equivalent local variations and modifications without departing from the spirit and scope of the invention.

100‧‧‧ Heterojunction bipolar transistor

110‧‧‧base platform

111‧‧‧ base electrode

112‧‧‧Base guide hole

120a, 120b‧‧ ‧ emitter

121a, 121b‧‧ ‧ emitter electrode

130‧‧‧ Collector

131a, 131b‧‧‧ collector electrode

Claims (8)

A heterojunction bipolar transistor comprising: an elongated base platform having an aspect ratio ranging from 3:1 to 15:1; a long strip base electrode a long axis of the base platform is disposed on the base platform, and a base via hole is disposed at or near the center of the base electrode; two elongated emitters are respectively located at the base On the platform, on both sides of the base electrode, and each of the emitter regions is provided with an elongated emitter electrode thereon; a long strip collector located below the base platform; The strip-shaped collector electrodes are respectively located above the collector and opposite sides of the base platform. The heterojunction bipolar transistor according to claim 1, wherein the base electrode is disposed along the long axis of the base platform on the base platform and at the center of the short axis of the base platform. Or near the center. The heterojunction bipolar transistor according to claim 1 or 2, wherein the base platform, the emitter electrode and the collector electrode are all rectangular. The heterojunction bipolar transistor according to claim 1 or 2, wherein the base platform, the emitter and the collector are bent long strips, and the bend is located in the strip At the center of the shape or near the center. The heterojunction bipolar transistor according to claim 1 or 2, wherein the base platform, the emitter and the collector are bent long strips, and the bend is located in the strip At or near the center of the shape, the angle of the bend is 90°. A heterojunction bipolar transistor comprising: an elongated base platform having an aspect ratio ranging from 3:1 to 15:1; an I-shaped emitter located at the base On the pole platform, a recessed portion is respectively disposed on two sides of the I-shaped portion, and two elongated emitter electrodes are disposed on the I-shaped emitter region; Two base electrodes are respectively disposed on the base platform and recessed on both sides of the I-shaped emitter, and each base electrode is provided with a base guide at one end of the base plate adjacent to the center of the base platform a hole; a long strip collector located below the base platform; and two elongated strip collector electrodes respectively located above the collector and opposite sides of the base platform. The heterojunction bipolar transistor according to claim 6, wherein the concave portion of the I-shaped emitter is disposed at or near the center of the short axis of the base platform. The heterojunction bipolar transistor according to claim 6 or 7, wherein the base platform and the collector electrode are rectangular.