JPS61219171A - Multi-cell type transistor - Google Patents

Abstract

PURPOSE:To improve the secondary breakdown voltage by a method wherein resistance films are formed along the first straight line connecting a pair of openings to each other and then the resistance films are also formed along the second straight line orthogonal to the first straight line while both ends of resistance films along the second straight line are connected to emitter wiring conductors. CONSTITUTION:An emitter stabilizing resistance films 18 almost crosswise formed are connected to emitter connecting electrodes 16a, 16b of the first and the second openings 21, 22 simultaneously to the first and the second emitter wiring conductors 15a, 15b. The first and the second openings 21, 22 are provided on the first straight line L1 corresponding to a bisector in one direction of unit emitter regions 11a as well as on the positions equidistant from the second straight line L2 corresponding to another bisector in the other direction. The second straight line L2 orthogonal to the first straight line L1 passes through the central part between the first and the second openings 21 and 22. The emitter stabilizing resistance films 18 are symmetrically formed centering on the first and the second straight lines L1 and L2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-cell transistor with an emitter stabilizing resistor that is not easily burnt out.

[Conventional technology]

In order to meet the demands for improved efficiency such as larger currents, faster switching, and higher frequencies, there are many types of transistors that are made up of a large number of cells (small transistors), such as multi-emitter type or mesh emitter type (base island type). It has been commercialized.

In this multi-cell transistor, it is common practice to connect a resistor (called an emitter stabilizing resistor) in series to the emitter of each cell in order to improve the secondary breakdown resistance χ. 14 is a partial plan view showing an example of a conventional multi-emitter transistor. (1) shows a unit emitter region constituting a cell;
(2) is the base area. This unit emitter area (1
Although not shown in FIG. 1, an insulating film is formed on the surfaces of the base region (2) and the base region (2). (3) is an opening for emitter connection provided in this insulating film, (4) (51 is an emitter wiring arrangement body, (6) <7> is a polysilicon resistive film, and (8) is an opening provided in the above insulating film. hole for base connection,
(9) is a base wiring conductor. In this structure, the resistance Rt obtained by the polysilicon resistance films (6) (7)
, Rt is the emitter region (1) and the emitter wiring conductor (
4) and acts as an emitter stabilizing resistor. There are various connection structures for emitter stabilizing resistors, but as shown in Fig. 14, two resistive films (61 (
7) It is easier to obtain an appropriate resistance value by connecting two in parallel.
, is also frequently used because it is convenient for pattern design.

[Problem that the invention seeks to solve]

However, further improvement was required regarding the reverse bias secondary breakdown resistance of L-load switching circuits and the like.

In other words, when the test conditions for reverse bias secondary breakdown strength are made stricter, the resistance film (6) or There is a problem in that (7) is burned out, the resistance value of these cells decreases, and current is concentrated in the cell, leading to secondary destruction, and an improvement is desired.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multi-cell type transistor which prevents burnout of the emitter stabilizing resistor and has a high reverse bias secondary breakdown resistance.

[Means for solving the problem]

In order to facilitate understanding, the present invention for achieving the above objects will be described with reference to the reference numerals in the drawings showing the embodiments.

The collector region trap is arranged to be adjacent to an adjacent base region of a second conductivity type, and to be adjacent to the base region on a side opposite to the collector region.

and a first conductivity type emitter region having a plurality of island-like portions, net-like portions, or stripe-like portions, and a first conductivity type emitter region provided on the surfaces of the emitter region and the base region. three edge films, emitter connection openings provided in the insulating film on the plurality of unit emitter regions constituting the emitter region, and emitter wiring conductors for connecting the plurality of unit emitter regions in parallel; A multi-cell transistor comprising a base wiring conductor connected to the base region, and a resistive film provided between the unit emitter region and the emitter wiring conductor.

First and second emitter connection openings (211) are provided corresponding to the unit emitter region (11a), and the first
The area along the first straight line connecting the center of the emitter connection hole (21) (22J and the center of the second emitter connection hole) and the first and second emitter connection hole (21)
2D (I perpendicular to the first straight line at approximately the center between 221
@20 A resistive film (111 g long) is provided in the region along the straight line, and both ends of the resistive film in the region along the first IL line are
and second emitter connection hole (211+221 y!
- connect the terminal or emitter through the pole (16a) <16
b)' are respectively connected to the unit emitter region (11a), and both ends of the resistive film in the region along the second straight line are respectively connected to the emitter wiring conductor (15aJ (15bJ). This relates to multi-cell transistors.

[For production]

The operation of the resistive film (181) of the above invention will be explained in comparison with the operation of the conventional resistive film (6) shown in FIG. 14. (7)
This shows the flow of current at . This resistive film (6
)(7), the resistance M(6)(7)
The path of the transient current that flows when the switch is turned off is arrow E!
As shown in J(251＠＠＠, it is thought that the central part (
0■] exceeds the allowable value, the area burns out, the resistance value decreases, and the current concentrates in the unit emitter region (cell) to which this resistive film (6) (7) is connected, resulting in The next step is destruction. - In the resistor Fc film according to the present invention shown in FIG. 7, the emitter wiring conductor (15a) (1
The path of the current flowing in 5b) is arrow l:l] 09 C3G
311 (roughly divided as shown in 321. A pair of ends B'B (18a) of the resistive film α connected to the emitter
The current flowing out from the emitter wiring conductor (151) tries to deviate to the central part ■[F] as in the case of Fig. 6, but the direction of flow is forcibly bent to the right angle direction.
(151)). As a result, current flow is prevented, burnout of the resistive film α& is less likely to occur, and secondary damage due to reverse bias is reduced.

〔Example〕

Next, a multi-emitter type silicon transistor according to an embodiment of the present invention will be described based on FIGS. 1 to 4. Figure 1 is a plan view showing the transistor with the insulating film omitted, Figure 2 is an enlarged plan view of part of the first factor, and Figure 3 is the third factor.
AA sectional view of the figure.

FIG. 4 is a sectional view taken along line BB in FIG. In order to clearly distinguish between each part, we will refer to the plan views of FIGS. 1 and 2 and other embodiments to be described later.

The emitter and base connecting conductors αη are shaded.

In the figure, αD is an N-type (first conductivity type) emitter region, σZ is a P-type (second conductivity type) base region, and a& is Nu
High resistance collector region, [41 is Rin resistance collector region,
(15a) and (15b) are first and second emitter wiring conductors made of an AI film; (16a) and (36b) are poles for emitter connection 1; (17a) are base wiring conductors made of an AI film.

u8 is an emitter stabilizing resistor made of polysilicon film, σ
l is a collector made of Ni film, (20) is Sin,
-8i.

An insulating film consisting of a two-layer film of R4, C+11 (221Ω is an opening provided in the insulating film ridge).

The emitter area waII is a large number of unit emitter areas (11a) arranged like islands y! ′, the base region α force is arranged like a mesh on the chip surface. Although only 12 unit emitter regions (tla) are shown in FIG. 1, in reality there are many (for example, 200).

The first and second portions correspond to each unit emitter region (11a).
emitter wiring conductors (15a) (15b) are provided,
Furthermore, a common connection part (15C) is provided to connect these parts in common. First and second emitter wiring conductors (15
a) (15b) is the first and second portion provided at the edge of the insulating film.
It is parallel to the first σ line connecting the emitter connection openings of , and has an equal spacing.

The base wiring conductor (17a) is the emitter wiring conductor (1
5aJ (lsb) and extends parallel to the base connection hole c! provided in the insulating film ■! It is connected to the base area via 31. Note that each base wiring conductor (17a) is connected to a common connection portion (17b). Further, the openings are provided corresponding to the corners of the unit emitter region (11a).

The emitter stabilizing resistive film ae is formed in a substantially cross shape, and the first
and the emitter connection electrode (16a) of the [phase] of the second opening.
(16b), and is also connected to the first and second emitter wiring conductors (15a) and (15b).

The first and second openings 1211I221 are provided above the first M line corresponding to the bisector of the unit emitter region (11a) in the -10,000 direction, and are provided above the bisector of the unit emitter region (11a) in the other direction. A second @ line corresponding to the above is provided at an equal distance. R1 is the second straight line, is the first straight line aL
1 and passes through the center between the first aperture opening and the second aperture. The emitter stabilizing resistive film is formed symmetrically around the first and second straight lines Lx and Ltya'.
Ru. One end (]sa) of the region along the first straight line LI of this emitter stabilizing resistive film connects the first emitter connection to the pole (
16a), the other end (18b) is connected to the second emitter connection 11 (16b), and one end (4sc) of the area along the second straight line is connected to the first emitter wiring conductor. (15a), and the other end (18d) is connected to a second emitter wiring conductor (15b).

A base current of waveform 24 as shown in FIG. 5 is caused to flow through the transistor configured as described above to perform switching operation, and the collector current s/B (averaged value value) to cause secondary destruction was determined. At this time, t pressure 't-m of 5oov by diode clamp method between collector and emitter,
It,, connect the coil χ with load L'CL = 208 mH, fix the positive direction base current I' in Fig. 5 to 2.5A, and change the pulse width W'PK of this positive direction base current IBsT. Collector current IS/
The value of B was measured. The value of the reverse base current (B) was varied in three steps: -1, OA, -2° OA, and -3, OA, and the respective values were determined.

7B As a result, Ts/B when IB, = -1, OA is ]2Δ
.

Is/B when I=-2, OA is】】A.

T6/B when IB,=-0.3A was IOA.

For comparison, IYlffl+ was determined in the same manner as in the first embodiment except that the resistive film Ql' was not provided.

When S/B = -1, OA, Is/B is 2A, IB,
=-2, OA and I=-3, I8/B when OA is 2A
B! It was less than Moreover, the resistance value is the resistance film of the first example (
181, except that the pattern was changed to the resistors M(6) and (7) shown in FIG. 14, and the other parts were the same as in the first embodiment, and I-Y measurements were performed. S/B IB, =-: When l and 0Δ, the engineering S/B is 7A.

Rice, = -2, l87B when OA is 2A.

Is/B was 2A when IB,=-3,OA.

As is clear from these measurement results, the effect of improving secondary fracture corrosion resistance is already apparent when <, -, = -1, OA, and IB! =
-2, OA time nine has been significantly revised! - to be done. This improvement effect appears to occur for the reasons already explained with reference to FIGS. 6-7.

Next, a transistor according to a second embodiment shown in FIGS. 8 to 11 will be explained. However, in the drawings of this second embodiment and the 12th tooth, 13-1, and 15, which will be described later, the same reference numerals are given to the parts common to the 1st to 4th cases, and the explanation thereof will be given. omitted.

In this second embodiment, an emitter stabilizing resistor film made of an Al film is provided in place of the emitter stabilizing resistor film of the polysilicon family shown in FIGS. 1 to 4. This resistance M
Z is the same material as the emitter wiring conductors (15a) (15b) and the emitter connection t% (Isa) (16b).
Al), but with a smaller width and/or thickness.

It is formed so that a desired resistance value can be obtained by reducing the cross-sectional area χ. For example, emitter wiring conductor (
15a) (15b) has a width of 30 μm and a thickness of 5 μm, whereas the width of the resistive film is 30 μm.

The thickness is 1 μm. The transistors shown in FIGS. 8 to 11 have the same structure as the transistors shown in FIGS. 1 to 4, except that the material of the resistive film i2a is changed.

When the collector current (2) which leads to secondary breakdown of the transistor in the second embodiment was measured at 7B using the same method as in the first embodiment, when IB = -1 and OA, the current /B was 6A.

IS/B is 5A when IB, = -2, OA.

■s/B when 1B, = -3, OA was 5A.

It is clear from this result that when <,IB, is large.

In other words, an improvement in secondary breakdown resistance was introduced during deep reverse bias. In the second embodiment, the resistance value of the emitter stabilizing resistor MG is the same as that of the conventional resistors (6) and (7) in FIG.
The resistance value of,! The reason why the secondary breakdown resistance is improved during deep reverse biasing is that the resistive film (2) is formed in a cross shape, even though it is small and is a disadvantageous value for emitter stabilization. In addition, when using this AIM as a barrier,
Burnout causes the emitter to become open, increasing the burden on other cells and leading to their destruction.

As in this embodiment, the resistor film opening is connected to the emitter wiring conductor (15a
) (15b) etc., the manufacturing process can be simplified and costs can be reduced. Note that the resistance of the structure of the 14th factor (61 (71) is Al
If you try to configure it with g, it is difficult to obtain the necessary resistance value within a practical length range, and even if the necessary resistance value is obtained, secondary damage is likely to occur ('.

[Modified example]

The present invention is not limited to the embodiments described above, but the following modifications are possible, for example.

] As shown in Figures 12 and 13, the base area a
The present invention can also be applied to a mesh emitter type transistor (base island type transistor) in which the emitter region C11l is arranged in a mesh shape.In this case, the unit emitter region Uta
) are provided corresponding to the first and second openings Gl+, and these and the first and second emitter wiring conductors (15a) (15
As shown in FIG. 12, between the button b) and the first
As shown in Figure 3, the resistance M of the AI film is the same as in the second embodiment.
Provide a link. As a result, the same effects as in the first and second embodiments can be obtained.

B+ As shown in FIG. 15, in a mesh emitter type transistor, emitter connection openings 1211 are regularly and repeatedly arranged, and a resistive film made of a cross-shaped polysilicon film is placed between each opening (2Il). Or AI
A resistive film made of a film may be provided. In this case, the opening f211@ serves also as the adjacent unit emitter region (11aJ).

(0 resistance film (181+331) may be formed of polysilicon, a resistance material other than AI, or a metal material.

The resistive film may be made of any material as long as it provides resistance.

0 Resistive film α8c (pattern 31) The pattern may not be exactly cross-shaped, but may also have a curved shape at the M portion.

Also, is the length of the portion along the first straight line of the resistive film (181r24J?) close to the width of the portion along the second straight line?

Alternatively, pattern deformation may be performed to make them equal.

[F] Resistance Jiua+c (31'v opening (211Ci
'21 as well, so as not to be directly connected to the emitter region σB.

〔Effect of the invention〕

As is clear from the above, according to the present invention, the resistance film Z is provided along the first straight line connecting the pair of openings, and the resistance y! is also provided along the second straight line orthogonal to the first straight line. Provided with
If both ends of the resistive film are connected to the emitter wiring barrel along this second straight line, the resistive film will be less likely to burn out, and the secondary breakdown resistance will be improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a transistor according to a first embodiment of the present invention. Fig. 2 is a partially enlarged plan view of Fig. 1, and Fig. 3 is the A-A lfi F! of the second fat. ft side view. FIG. 4 is a sectional view taken along the line B-B in FIG. 2. Figure 5 is a current waveform diagram for measuring the secondary breakdown collector current, and Figure 6 is a plan view showing the current flow in a conventional emitter stabilizing resistor. FIG. 7 is a plan view showing how current flows in the emitter stabilizing resistive film of the present invention, FIG. 8 is a plan view showing a transistor according to the second embodiment of the present invention, and FIG. FIG. 10 is a sectional view taken along the line A-A in FIG. 9; FIG. 11 is a sectional view taken along the line B-B in FIG. 9. Figures 12 and 13 are plan views showing a modified example of a transistor, Figure 14 is a plan view showing a portion of a conventional transistor, and Figure 15 is a plan view showing a portion of a modified transistor. FIG. 111l...Emitter region, (11a)...Unit emitter region. α force...base area, α3...collector area, (1
5a) (15b)...Emitter wiring conductor, bet...Emitter stabilizing resistive film. (2) Insulating film, c:n (221... Opening.

Claims (5)

[Claims] (1) a collector region of a first conductivity type; a base region of a second conductivity type adjacent to the collector region; arranged adjacent to the base region on a side opposite to the collector region; and a first conductivity type emitter region having a plurality of island-like portions, net-like portions, or stripe-like portions; an insulating film provided on surfaces of the emitter region and the base region; and the emitter region. Emitter connection holes provided in the insulating film on the plurality of unit emitter regions constituting the plurality of unit emitter regions, an emitter wiring conductor for connecting the plurality of unit emitter regions in parallel, and a base connected to the base region. In a multi-cell type transistor having a wiring conductor and a resistive film provided between the unit emitter region and the emitter wiring conductor, first and second emitter connection portions are provided corresponding to the unit emitter region (11a). an area along a first straight line connecting the center of the first emitter connection hole (21) and the center of the second emitter connection hole (22); The first and second emitter connection holes (21)
A resistive film (18) and (33) are provided in a region along a second straight line perpendicular to the first straight line at approximately the center between (22) and both ends of the resistive film in the region along the first straight line. connected to the unit emitter region (11a) directly through the first and second emitter connection openings (21) (22) or via emitter connection electrodes (16a) (16b),
A multi-cell transistor characterized in that both ends of the resistive film in the region along the second straight line are connected to the emitter wiring conductors (15a) (15b), respectively. (2) The resistive film is connected to the emitter wiring conductor (15a)
The multi-cell transistor according to claim 1, which is made of a material different from (15b). (3) The multi-cell transistor according to claim 2, wherein the resistive film is a polysilicon film. (4) The resistive film is connected to the emitter wiring conductor (15a) (
2. The multi-cell transistor according to claim 1, which is made of the same material as the emitter wiring conductors (15b) and has a cross-sectional area smaller than that of the emitter wiring conductors (15a) and (15b). (5) Both the resistive film and the emitter wiring conductor are made of Al.
5. The multi-cell transistor according to claim 4, which is a film.