JPH03268331A - Base modulation type bipolar transistor - Google Patents

Abstract

PURPOSE:To improve the area efficiency and the switching speed of a chip, by connecting a gate region with an upper collector region. CONSTITUTION:A P<+> base region 5 containing an emitter region 7 and a P<+> base contact region 6 are formed independently so as to put a gate region 8A between them. The gate region 8A reaches an upper collector region 4, and connected with the collector region 4 in a gate region 8B being the end portion of the collector region 4. Foward bias is applied across the base contact region 6 and the emitter region 7. The collector region 4 is backward biased to the base contact region 6. Thus a base current flowing through a second base region 3 is modulated, and an output having negative resistance characteristics is obtained. Thereby chip area efficiency and response characteristics can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a base modulation bipolar transistor having negative resistance characteristics.

[Prior art and its problems] Conventionally, a three-terminal device type base modulation bipolar transistor with negative resistance characteristics has a planar structure as shown in FIG. 7 and a cross section as shown in FIG. A device having a structure is provided. As shown in FIG. 7, the operating principle of a base modulated bipolar transistor device having a through-gate region reaching the collector region is described in detail in Japanese Patent Application No. 1-77128 by the same applicant.

In the base modulated bipolar transistor according to the conventional configuration example shown in FIGS. 7 and 8, the through gate region (8C) lowers the gate resistance of the gate region, and brings about the following characteristics.

Due to the operating principle of base modulated bipolar transistors,
The gate region absorbs some of the minority carriers injected into the base region, thereby causing a gate current to flow. The voltage drop in the gate region due to this gate current is reduced by providing the through gate region, thereby preventing unstable negative resistance characteristics from appearing. Furthermore, since the gate resistance is reduced, the time constant for charging and discharging the gate region due to the gate current can also be increased.

However, as shown in FIGS. 7 and 8, conventional base modulated bipolar
In the transistor, the base current from the base contact region (6) flows into the emitter region (7) near the through gate region (8C).
), the emitter region near the through-gate region does little work, resulting in poor chip area efficiency and even having a negative impact on response. Furthermore, when forming the through gate region H (8C) reaching the collector region (2), its lateral diffusion cannot be ignored.
Similarly, chip area efficiency and responsiveness are adversely affected.

Furthermore, the through gate fR region (8C) needs to be formed in the bent portion of the emitter region (7) or the head contact R region (6) due to its lateral diffusion.
There were problems such as difficulty in equally dividing the gate resistance depending on the through-gate region.

[Problem to be Solved by the Invention J] Therefore, the present invention solves the problem of penetrating game h reaching the collector region.
The purpose of the present invention is to solve various problems of the base modulated bipolar transistor in the prior art having a region A part, and to provide a base modulated bipolar transistor with a new structure configured to operate with three terminals. .

[Means for Solving the Problems] In achieving the above object, the present invention specifically includes: a collector region made of a semiconductor material of a first conductivity type; and a first PN with respect to the collector region. a base region made of a semiconductor material of a second conductivity type formed through a junction; and an emitter region made of a semiconductor material of a first conductivity type formed with respect to the base region through a second PN junction. and the base region is opposite to the emitter region, and the base region is
a first base region adjacent to each other via a PN junction, and a base contact region located at a distance from the first base region, from which the base electrode is taken out
a second base region with a low impurity concentration formed between the first base region and the base contact region; A gate region having a first conductivity type is provided in the base region of No. 2, and the collector region has an upper collector region portion that limits the base region on the base region side and reaches the upper surface of the semiconductor device. , a portion of the gate region is located on the upper collector region, a gate-collector connection is formed between the gate region and the upper collector region, and a forward bias is applied between the base contact region and the emitter region. and energizes the collector region to a reverse bias state with respect to the base contact region to modulate the base current flowing through the second base region to obtain an output having negative resistance characteristics. This constitutes a base modulation type bipolar transistor.

[Function] In the base modulated bipolar transistor of the present invention configured as described above, the base current flowing from the base contact region to the emitter region is as follows:
The flow does not bypass the through-gate region, but instead flows directly under the gate region, allowing the emitter region to function effectively, resulting in extremely high chip area efficiency. If anything, it also improves the switching speed. Furthermore, since the gate resistance in the gate region can be reduced as much as possible while being divided into equal parts, the degree of freedom in chip pattern design is greatly expanded, and it can be applied to any base modulation type bipolar transistor, from small signal use to power use. It becomes possible to respond. Also,
Part of the gate region reaches the collector region, so
The gate region is maintained at the same potential as the collector region, and can be operated with three terminals.

[Embodiments of the present invention] Hereinafter, a base modulation bipolar transistor according to the present invention will be described.
ar Transistor (hereinafter abbreviated as BAMBIT) will be described in detail based on a specific embodiment shown in the drawings. In the detailed description of the present invention, an NPN type semiconductor device will be exemplified when silicon is used as the semiconductor material. however,
This invention can also be applied to other compound semiconductors as semiconductor materials, and can also be configured into a PNP type semiconductor device.

In this invention, RAMBI which is the first embodiment
A schematic plan view of T is shown in FIG.
Figure 2 shows a schematic cross-sectional view enlarged along the line -■.
A schematic cross-sectional view enlarged along the line (2) is shown in FIG. 3. In the examples shown in FIGS. 1, 2, and 3, first,
An N-collector layer (2) is formed on the N-high impurity concentration substrate (1).
) at an impurity concentration of about 10 atoms/C-, about 5 to 1
Vapor phase growth is performed to a thickness of about 5 μm. Subsequently, the N-
10 P-base layers (3) are placed on the top surface of the collector layer (2).
Epitaxial growth is performed to a thickness of about 1 to 3 μm at an impurity concentration of about atoms/cd. Next, using the P-base layer as a base region, an upper collector region (4) of N'' to be separated from the N-collector layer (2) is formed with an impurity concentration of 10.
It is formed by diffusion or ion implantation to an extent of 1/- atom. An F base region (5) is diffused or ion-implanted into a part of the isolated P base region (3) to an impurity concentration of about 10 i atoms/C. This Y base region (5) is defined as a first base region, and the P-base region (3) is defined as a second base region. Next, with respect to the P-base region (3), the first base region (5)
An F-base contact region (6) is formed with the P-base region (3a) separated from the P-base region (3a). The F base contact region (6) may be formed simultaneously with the first F base region (5). On the other hand, both the Y base region (5) and the P base contact region (6)
- It may be deep enough to reach the collector layer (2), or in some cases, it may be deep enough not to reach the N-collector layer (2). Subsequently, an N emitter region 7) is formed inside the P base region 5) with impurity concentration and depth selected so as to provide a desired current amplification factor hp. Subsequently, the F base region (5
) by diffusion or ion implantation. In this invention, the gate region (8) is located within the second base region (3) and does not reach the collector region (2) as a whole, but is partially located within the upper collector region (2). 4) Gate region portion (8A
) and a second gate region (8B) reaching the upper collector region (4). In the example shown in the figure, the Y base region (5) including the emitter region (7) and the F base contact region (6) are independent with the gate region (8A) in between, and the gate region (8A)
Since the BAlfBIT is operated with three terminals, it reaches the upper collector region (4) and is connected to the collector region at the gate region (8B) which is the terminal portion thereof. Furthermore, in the embodiments shown in FIGS. 1, 2, and 3, there are a plurality of emitter regions (7) and Y base contact regions (6), each of which is connected in parallel with a wiring material. In the figure, reference numeral (9) indicates an oxide film.

On the other hand, in the present invention, electrodes are formed using a desired metal material such as aluminum for the Y base contact region (6) and the N emitter region 7) using well-known techniques. Each electrode has a Y base contact area (6
), an emitter electrode (11) for the emitter region (7), and a collector electrode (12) for the collector region (1).

Next, as described above, BAMB is provided with a gate region portion (8B) that reaches the upper collector region (4).
The operating principle of IT will be explained. First, the movement of the carrier is as shown below. The P° base contact region (6) and the emitter region (7) are put into a forward bias state, and the P° base contact region (6) and the collector region (
2) into a low reverse bias state. In this way, electrons, which are minority carriers, are absorbed from the emitter region (7) to the P base region 5), and most of them are drawn into the collector region (2) as in a normal transistor.
The internal collector current is 1 cr, and a part of it is connected to the first gate a.
It is absorbed by the region (8A) and becomes an internal gate current IO+.

Also, some electrons are transferred to the P-base region (5) or the P-base region (5).
Base region (3) to F base contact region (6)
to recombine. In order to supplement the holes, which are majority carriers recombined with the electrons, holes are injected from the F-base contact region (6) into the P-base region (3). As a result, the base current flows directly under the gate region (8A)! B will flow. From this state, when the reverse bias of the collector region (2) and the F base contact region is gradually increased, the gate region (8B), which is the terminal part of the gate region (8A), and the upper collector region (4)
Since these are connected at the gate-collector connection portion (C, P), almost the same reverse bias as that of the collector region (2) is applied to the gate region (8A) as well. Then, the depletion layer invades into the P-base region (3) from the gate region (8A) and collector region (2). As a result, the electrons injected from the emitter region (7) are
The proportions absorbed by the gate region (8^) and the collector region (2) each increase, increasing the current amplification factor for the internal gate current IGi and the internal collector current IC1.

On the other hand, for holes, which are majority carriers injected from the F base contact region (6), the free charge region becomes narrower, and the injection by holes is suppressed more than the current amplification factor increases, resulting in a recombination current. decrease. Due to this effect, for the reverse bias voltage between the collector and the base,
The Y base region (3) is modulated, the base current]B is modulated, the amplified internal collector current lCI and internal gate current 1G+ exhibit negative resistance characteristics, and the internal collector current (cr and internal The output collector current 1c, which is the sum of the gate current Jar, exhibits negative resistance characteristics.Furthermore, when the reverse bias voltage between the collector and the base is increased, the P-base region <3> becomes a hole, which is the majority carrier. is pinched off, and the base current IB and collector current IC are cut off.

In connection with BANBIT, which is the present invention, Japanese Patent Application No. 1-77128 filed by the same applicant discloses that the BANBIT as a three-terminal device is
A RAM old T with a through-gate region extending to the collector region for BIT purposes is described in detail. However, this conventional BAMBIT has the following problems.

This conventional example of BANBIT will be briefly explained based on the plan view shown in FIG. 7 and the schematic sectional view shown in FIG. 8. In the conventional BAM old T shown in FIG. 7, the gate region (8A) absorbs minority carriers and an internal gate current IGi flows. And this gate current (
By reducing the voltage drop in the gate region (8A) due to a+ as much as possible and eliminating unstable negative resistance characteristics, switching
In order to increase the speed and to operate BAMBIT with three terminals, a through gate region (8C) reaching the collector region (2) is provided.

However, in the conventional example shown in FIG. 7, the current flowing from the base region (6) to the emitter region (7) avoids the through gate region (8C). Therefore, for example, the emitter region near the through gate region (8C), as shown by the symbol (M) in FIG. 7, does not work much due to the potential drop of the base current. Therefore, the area efficiency of the chip as a whole deteriorates, and due to the unnecessary junction area, the junction capacitance becomes large and the switching speed becomes slow. In addition, since the through gate region (8C) reaches the collector region (2), lateral diffusion cannot be ignored when forming the through gate region (8C). The area after diffusion becomes larger than the area, and exceeds the gate length that should be formed as the minimum line width. Therefore, as described above, this also has a negative effect on the area efficiency and switching speed of the chip.

Furthermore, in the example shown in FIG.
If the through gate region (8C) is not formed at the turning point, pattern design will be difficult due to the bulge of the through gate region (8C) as described above.
7, the gate lengths from one through gate region to another through gate region are no longer uniform, which also causes problems such as unfavorable characteristics.

For these problems of the old BA 11T, which is a conventional example,
In the first embodiment of the present invention shown in FIG. 1, the above problem is solved as follows. First, in order to operate BAMBIT as a three-terminal device, the gate region (88)
is connected to the upper collector region (4) at the terminal portion (8B) of the gate region and at the gate-collector connection portion (C, P). As a result, F including the emitter region
The base region (5) and the g-base contact region (6) are separated by a gate region (8A). Therefore, since each separated region is connected by wiring, the base current from the base contact region (6) to the emitter region (7) is It flows effectively through each area width, making the chip area efficiency much better than in the conventional example, and improving switching speed. Further, as is clear from FIG. 1, the gate regions (8A) are also formed independently and have the same length, so that the gate regions (8A) are divided by the through gate regions as in the conventional example. - The variation in gate resistance in the gate region is also eliminated. And in order to further reduce gate resistance,
If the width wn of the entire base region including the F base region (5), F base contact region (6), and P-base region (3) shown in FIG. 1 is further shortened, the gate width is shortened. , the gate resistance can be easily lowered. Also,
The output current value can be determined by changing the number of independent base contact regions and emitter regions. Therefore, it is possible to arbitrarily design the number of emitter regions from one to several thousand depending on the output current.

Furthermore, the present invention solves the problem of lateral diffusion caused by the formation of the through-gate region, which was a problem in the conventional example, and further improves the area efficiency of the chip.

Next, B which becomes the second embodiment of this invention shown in FIG.
The configuration of AMBiT will be explained. BAMBIT, which is the second embodiment, has a P base region in order to further lower the gate resistance. The entire base region including the base contact region and the P-base region is also divided, and the gate resistance is 1/2 that of the first embodiment. By separating and making the entire base region independent in this way, compared to the case where the base region width IJa described in the first embodiment was shortened simply to reduce the gate resistance, the entire device The degree of freedom in pattern design is further improved. In other words, BA for high output power? In IBIT, etc., if a single base region is used, the device becomes rectangular, but by forming multiple base regions independently, including the 2 base region, the P base contact region, and the Y base region. , it is possible to design an arbitrary device shape even if the gate resistance is sufficiently lowered.

Next, a third embodiment of BAMBIT according to the present invention will be described based on FIG. The embodiment shown in FIG.
For the purpose of further lowering the gate resistance, the gate region (8
It consists of four gate region sections taken out from A> and connected to the upper collector region (4) at each terminal section (8B). BAMBIT in this form
is effectively suited for small signal applications, integrated circuit applications, etc.

Furthermore, a fourth embodiment of BAMBIT according to the present invention will be explained based on FIG. The embodiment shown in FIG.
This is applied to the photoelectric conversion element disclosed in Japanese Patent Application No. 1-77129 filed by the same applicant, and of course obtains bistable current and voltage outputs with respect to optical input. In this figure, symbol (14) is the light receiving part of the phototransistor part, (
15) is the emitter region of the phototransistor section, (16)
) indicates a ground electrode, and (17) indicates a control electrode, respectively.

In addition, this invention can be used in combination with a through gate region, and can also be applied when the gate region has a MOS gate structure or a Schottky junction. BAMBIT for work,
The application of photo BAMBIT and even integrated circuits is not limited to the above embodiments.

[Effects of Example 1] The base modulation type bipolar system of the present invention having the above configuration
Transistors have a number of effects described below.

(i) By connecting the gate region to the upper collector region, the emitter region and the F base contact region can be used effectively, increasing the area efficiency of the chip and greatly improving the switching speed.

(ii) By connecting the gate region to the upper collector region, gate resistance can be reduced as much as possible.

(ii) By connecting the gate region to the upper collector region, the entire base region including the P-base region, P-base region, and Y-base contact region can be separated and made independent, keeping the gate resistance low. , it can be designed into any element shape.

(iv) As a method for connecting the gate region to the upper collector region, it is sufficient to simply perform it on the pattern, and there is no additional process compared to the conventional process.

(v) By connecting the gate region to the upper collector region, it can be operated as a three-terminal device.

As described above, the BAMBIT according to the present invention, in which the gate region is connected to the upper collector region, operates as a three-terminal negative resistance device in the same way as the conventional example, and the gate resistance value is lowered and the switching speed is increased. west,
Its effects are enormous in applications ranging from small signals to high-frequency, high-output, high-output, high-speed memories, and even integrated circuits.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing a concrete first embodiment of the base-modulated bipolar transistor according to the present invention, and FIG. 2 is a schematic plan view taken along the line ■-■ in FIG. 3 is a schematic sectional view taken along line I-III in FIG. 1, FIG. 4 is a schematic plan view showing the second embodiment of the BAMBIT, and FIG. A schematic plan view showing a third embodiment of RAMBIT, FIG. 6 is a schematic cross-sectional view showing a fourth embodiment of BAMBIT, and FIG. 7 is a schematic plan view showing a conventional BAMBIT. , FIG. 8 is a schematic sectional view taken along the line ■-■ in FIG. 7. (1), (2)... Collector area (3)...
... Second base region (4) ... Upper collector region (5) ... First base region (6) ... Base contact region ( 7)...
...Emitter region (8A) ...Gate region (8B) ...Gate region terminal part (9) ...
...Oxide film (10) ...Base electrode (11) ...Emitter electrode (12) ...Collector electrode (14) ...Phototransistor section The light receiving part (
15)...Emitter region of phototransistor section (16)...Ground electrode (17)...Control electrode

Claims (1)

[Claims] A collector region made of a semiconductor material of a first conductivity type; a base region made of a semiconductor material of a second conductivity type formed with the collector region via a first PN junction; , an emitter region made of a semiconductor material of a first conductivity type formed via a second PN junction with respect to the base region;
a first base region adjacent to each other via a PN junction; a base contact region located at a distance from the first base region and formed to take out the base electrode;
a second base region with a low impurity concentration formed between the first base region and the base contact region; A gate region having a first conductivity type is provided in the base region of No. 2, and the collector region has an upper collector region portion that limits the base region on the base region side and reaches the upper surface of the semiconductor device. , a portion of the gate region is located on the upper collector region, and forms a gate-collector connection with the upper collector region, and forward bias is applied between the base contact region and the emitter region. biasing the collector region against the base contact region;
A base modulated bipolar transistor characterized in that it is energized to a reverse bias state to modulate the base current flowing through the second base region to obtain an output having negative resistance characteristics.