JPH05304162A - Semiconductor device - Google Patents

Abstract

PURPOSE:To realize integration on the same semiconductor substrate as other elements or semiconductor circuits by forming second conductivity type emitter region and base region on the surface of a first conductivity type semiconductor substrate and forming a first conductivity type collector region on the surface of the base region. CONSTITUTION:A collector region 6 is formed on the surface of a base region 8 while an emitter region 6 and a substrate contact region 5 are formed on an epitaxial layer 11 while being spaced apart from the base region 8 and a gate insulation film 3a is formed on the epitaxial layer 11 between the base region 8 and the emitter region 6. A collector electrode 1 is formed on the contact region 9 and an emitter electrode 2 is formed on the emitter region 6 and the substrate contact region 5. Furthermore, a base-collector region 5 is formed at a position remote from the collector region 6. This constitution realizes formation of emitter electrode, gate electrode, and collector electrode to be applied with high voltage on a semiconductor substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device,
In particular, it relates to a gate drive type bipolar transistor which is a kind of power device used for motor control and the like.

[0002]

2. Description of the Related Art A conventional gate drive bipolar transistor is of a vertical type, and its sectional structure is shown in FIG. The conventional gate drive bipolar transistor shown in FIG. 2 is an n-channel type. In FIG. 2, 13 is an emitter electrode, 14 is a gate insulating film, 15 is a gate electrode,
16 is an n-type emitter region, 20 is a p-type collector region, 21 is a p-type semiconductor region 17, and n-type semiconductor region 1
This is a base region composed of 8 and 19.

As shown in FIG. 2, in a conventional gate drive bipolar transistor, a base region 21 made of semiconductor regions 17, 18 and 19 is formed on a collector region 20 made of a semiconductor substrate, and the base region 21 is formed on the surface of the semiconductor region 17. The emitter region 16 is formed, the gate insulating film 14 is formed on the semiconductor region 18 between the adjacent emitter regions 16, the gate electrode 15 is formed on the gate insulating film 14, and the emitter region 16 and the semiconductor region 17 are electrically connected. The emitter electrode 13 that is electrically connected is formed.

The operation of the conventional gate drive type bipolar transistor thus constructed will be described. First, when a positive voltage is applied to the gate electrode 15, an n-type channel is formed in the p-type semiconductor region 17 directly below the gate insulating film 14. p-type collector region 20 and n-type semiconductor region 1
8 and 19 are forward-biased, holes are in the collector region 20.
To the n-type semiconductor regions 18 and 19. This flow of holes is absorbed by the potential gradient between the p-type semiconductor region 17 and the n-type semiconductor region 18, and the emitter electrode 13
To reach.

That is, by applying a positive voltage to the gate electrode 13, a bipolar transistor operation occurs, and the resistance component between the emitter region 16 and the collector region 20 is greatly increased due to the conductivity modulation of the n-type base regions 18 and 19. Will be reduced.

[0006]

However, the conventional gate drive type bipolar transistor having such a structure is of a vertical type, and the collector electrode (not shown) to which a high voltage is applied becomes the collector region 20. Since it is formed on the back surface of the semiconductor substrate, it can be manufactured and used as an individual element, but there is a problem that it cannot be integrated in the same semiconductor substrate as other elements and semiconductor circuits.

In view of the above problems, it is an object of the present invention to provide a semiconductor device which can be integrated on the same semiconductor substrate with other elements and semiconductor circuits.

[0008]

According to another aspect of the present invention, there is provided a semiconductor device having a second conductivity type base region formed on a surface of a first conductivity type semiconductor substrate and a first conductivity type formed on a surface of the base region. Type collector region, an emitter region formed on the surface of the semiconductor substrate at a predetermined distance from the base region, and a first conductivity type semiconductor formed on the surface of the base region between the collector region and the emitter region and connected to the semiconductor region. Region, a gate insulating film formed on the semiconductor substrate between the base region and the emitter region, a gate electrode formed on the gate insulating film, a collector electrode electrically connected to the collector region, the emitter region and the semiconductor substrate And an emitter electrode electrically connected to.

According to a second aspect of the present invention, in the semiconductor device according to the first aspect, the second conductive layer having a higher concentration than that of the base region is provided at a position on the surface of the base region that is farther from the collector region than the emitter region. The base contact region of the mold is formed, and the base contact region and the collector electrode are electrically connected.

[0010]

According to the structure of the present invention, the second conductive type emitter region and the second conductive type base region are formed on the surface of the first conductive type semiconductor substrate at a predetermined interval. Since the collector region of the first conductivity type is formed on the surface, the emitter electrode, the gate electrode and the collector electrode to which a high voltage is applied can be formed on the semiconductor substrate. That is, by making it horizontal compared to the conventional vertical type,
All the electrodes can be formed on the front surface side of the semiconductor substrate. Therefore, it becomes unnecessary to apply a high voltage to the semiconductor substrate as in the conventional case, and the semiconductor substrate can be grounded.

Further, when a high voltage is applied to the collector electrode by forming a semiconductor region electrically connected to the semiconductor substrate below the base region on the surface of the base region between the collector region and the emitter region, the base region is formed. Further, the depletion layer spreads between the semiconductor regions and between the base region and the semiconductor substrate below the base region, whereby the base region can be completely depleted. Therefore, by forming the semiconductor region, the base region can be completely depleted even if the impurity concentration of the base region is increased.

[0012]

1 is a sectional view showing the structure of a semiconductor device according to an embodiment of the present invention. Note that FIG. 1 shows an n-channel gate drive bipolar transistor. In FIG. 1, 1 is a collector electrode, 2 is an emitter electrode, 3 is an interlayer insulating film made of a silicon oxide film, 3a is a gate insulating film,
4 is a gate electrode made of polycrystalline silicon, 5 is a p-type base contact region having a higher concentration than the base region 8, 6 is a p-type collector region, 7 is a p-type semiconductor region, and 8 is an n-type base region. , 9 is an n-type emitter region, 10 is a substrate contact region made of a p ⁺ -type diffusion region, 100 is a p-type semiconductor layer 12, and an epitaxial layer formed on the semiconductor layer 12 and having a concentration lower than that of the semiconductor layer 12. It is a semiconductor substrate made of 11.

As shown in FIG. 1, the semiconductor device has a base region 8 formed on the surface of a semiconductor substrate 100 composed of a semiconductor layer 12 and an epitaxial layer 11, and a collector region 6 formed on the surface of the base region 8. An emitter region 9 and a substrate contact region 10 having a higher concentration than that of the epitaxial layer 11 are formed on the surface of the epitaxial layer 11 at a predetermined distance from the base region 8, and a gate is formed on the epitaxial layer 11 between the base region 8 and the emitter region 9. An insulating film 3a is formed, and a gate electrode 4 is formed on the gate insulating film 3a.
To form a collector electrode 1 electrically connected to the collector region 6, and further an emitter electrode 2 electrically connected to the epitaxial layer 11 via the emitter region 9 and the substrate contact region 10. .

Further, a base collector region 5 having a higher concentration than that of the base region 8 is formed on the surface of the base region 8 at a position farther from the emitter region 9 than the collector region 6, and the base collector region 5 and It is electrically connected to the collector electrode 2. Further, a p-type semiconductor region 7 is formed on the surface of the base region 8 between the collector region 6 and the emitter region 9, and although not shown, the p-type semiconductor region 7 is located below the base region 8. Epitaxial layer 1
1 is electrically connected.

The thickness of the interlayer insulating film 3 covering the substrate surface is set to 2 [μm] or more. As a result, a breakdown voltage of 400 [V] between the collector and the emitter was obtained. The operation of the semiconductor device configured as above will be described. First, when a positive voltage is applied to the gate electrode 4, n is immediately below the gate insulating film 3a.
A channel (not shown) of the mold is formed and the base region 8
(Corresponds to the drain region of the MOSFET) to emitter region 9 (corresponds to the source region of the MOSFET).
Current flows toward. This current increases and the voltage drop in the base region 8 below the collector region 6 is about 0.6.
When [V] (the collector region 6 and the base region 8 are forward biased) is reached, holes are injected from the collector region 6 into the base region 8. When the holes reach the depletion layer formed between the n-type base region 8 and the p-type epitaxial layer 11 by the reverse bias, they are extracted by the potential gradient and reach the emitter electrode 1. That is, by applying a positive voltage to the gate electrode 4, the collector region 6
(Corresponds to the emitter of a bipolar transistor.)
, A base region 8 (corresponding to the base of the bipolar transistor) and an epitaxial layer 11 (corresponding to the collector of the bipolar transistor) operate.

Further, when the operation is stopped by lowering the gate voltage, the base region 8 is depleted, and the potential gradient due to this depletion pulls out the holes in the base region 8, but the semiconductor under the epitaxial layer 11 is depleted. By making the layer 12 a p-type having a higher concentration than the epitaxial layer 11, the speed of extracting the above holes can be significantly improved.

The p-type semiconductor region 7 electrically connected to the epitaxial layer 11 is formed on the surface of the n-type base region 8.
Thus, when a high voltage is applied to the collector electrode 1, depletion occurs between the n-type base region 8 and the p-type semiconductor region 7 and between the n-type base region 8 and the p-type epitaxial layer 11. The layer spreads, which allows the base region 8 to be completely depleted. Therefore, by forming the p-type semiconductor region 7, the base region 8 can be completely depleted even if the impurity concentration of the base region 8 is increased. As a result, by increasing the impurity concentration of the base region 8, it is possible to reduce the occupied area of the base region and realize a high breakdown voltage.

As described above, according to the embodiment, the semiconductor substrate 1
00, the n-type base region 8 and the n-type emitter region 9 are formed at a predetermined interval, and the base region 8
Since the p-type collector region 6 is formed on the surface of, the emitter electrode 2, the gate electrode 4, and the collector electrode 1 to which a high voltage is applied can be formed on the semiconductor substrate 100.

That is, all electrodes can be formed on the front surface side of the semiconductor substrate 100 by adopting the horizontal type as compared with the conventional vertical type. Therefore, it becomes unnecessary to apply a high voltage to the semiconductor substrate 100 having the gate drive type bipolar transistor formed therein, which can be grounded. As a result, other elements (not shown) and semiconductor circuits (not shown) can be easily integrated on the same semiconductor substrate 100.

The same effects as those of the above-described embodiment can be obtained without forming the base contact region 5 shown in FIG. However, when the operation of the transistor is turned off (stopped) by forming the base contact region 5, the minority carriers existing in the base region 8 pass through the base contact region 5, so that the transistor is turned off (stopped). The switching time can be shortened. When the base contact region 5 is not formed, the minority carriers existing in the base region 8 have to be extinguished by recombination, and the switching time becomes longer than that when the base contact region 5 is formed.

[0021]

According to the semiconductor device of the present invention, the second conductivity type emitter region and the second conductivity type base region are formed on the surface of the first conductivity type semiconductor substrate at predetermined intervals. Since the collector region of the first conductivity type is formed on the surface of the base region, the emitter electrode, the gate electrode and the collector electrode to which a high voltage is applied can be formed on the semiconductor substrate. That is, by adopting the horizontal type as compared with the conventional vertical type, all electrodes can be formed on the front surface side of the semiconductor substrate. Therefore, it becomes unnecessary to apply a high voltage to the semiconductor substrate as in the conventional case, and the semiconductor substrate can be grounded.

As a result, other elements and semiconductor circuits can be easily integrated on the same semiconductor substrate. In addition, when a high voltage is applied to the collector electrode by forming a semiconductor region electrically connected to the semiconductor substrate below the base region on the surface of the base region between the collector region and the emitter region, the base region and the semiconductor region are The depletion layer spreads between the base region and the semiconductor substrate below the base region, which allows the base region to be completely depleted. Therefore, by forming the semiconductor region, the base region can be completely depleted even if the impurity concentration of the base region is increased.

As a result, by increasing the impurity concentration of the base region, the occupied area of the base region can be reduced and a high breakdown voltage can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of a conventional semiconductor device.

[Explanation of symbols]

 1 collector electrode 2 emitter electrode 3a gate insulating film 4 gate electrode 5 base contact region 6 collector region 7 semiconductor region 8 base region 9 emitter region 100 semiconductor substrate

Front Page Continuation (72) Inventor Yuji Ueno 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electronics Industrial Co., Ltd.

Claims (2)

[Claims] 1. A second-conductivity-type base region formed on the surface of a first-conductivity-type semiconductor substrate, a first-conductivity-type collector region formed on the surface of the base region, and a predetermined distance from the base region. An emitter region provided on the surface of the semiconductor substrate; a semiconductor region of a first conductivity type formed on the surface of the base region between the collector region and the emitter region and electrically connected to the semiconductor substrate; A gate insulating film formed on the semiconductor substrate between the base region and the emitter region; a gate electrode formed on the gate insulating film; a collector electrode electrically connected to the collector region; A semiconductor device having an emitter electrode electrically connected to a semiconductor substrate. 2. A second-conductivity-type base contact region having a higher concentration than that of the base region is formed on the surface of the base region at a position farther from the collector region than the emitter region,
The semiconductor device according to claim 1, wherein the base contact region and the collector electrode are electrically connected.