JPS5839060A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the damage of an emitter shortcircuiting part due to concentration of reverse recovery current flowing through a parasitic diode by forming an emitter electrode commonly connected to a plurality of emitter electrodes without connecting to the shortcircuiting part of emitter and base by utilizing a sheet resistor of an emitter layer. CONSTITUTION:Since a resistor 63 between the emitter and the base of a transistor 61 utilizes the sheet resistor of a P type layer 43 and a resistor 64 between the base and the emitter of a transistor 62 utilizes the sheet resistor of an N<+> type layer 484 since an emitter electrode 53 is not pressure connected through a buffer plate 52 to base and emitter shortcircuiting aluminum wire layer 51. In the state that a parasitic diode d between the layer 43 and an N<-> type layer 42, N<+> type layer 41 and resistors 65, 64 are connected in series between the collector and the emitter of the transistor 62, between the collector and the emitter is reversely biased, even if the diode d is forwardly biased, a reverse recovery current can be limited by the resistor 65.

Description

DETAILED DESCRIPTION OF THE INVENTION Jin's invention relates to a semiconductor device, and more particularly to a power element having a short-circuit structure.

FIG. 1 shows an equivalent circuit of a general Darlington transistor, in which resistors 3 and 4 are connected between the emitters and bases of the NPN transistor 1 at the front stage and the NPN transistor 1 at the rear stage, respectively. These resistors 3,
4 is a transistor! .

This is to prevent an increase in the leakage current of the collector at a high temperature, an increase in the switching speed, and oscillation of the transistors 1 and 2. Figure 2 shows this Darlington transistor 0 semiconductor chip! 5 is a sectional view showing a state in which the device 5 is sealed in an envelope (ceramic, Kugasu) 6. FIG.

Further, FIG. 3 is a sectional view based on a specific element structure of the Darlington transistor. In the same figure, 11
is IHl and 12 is formed on this N1 layer 11? QL
J g is the base P formed on this N112
It is a layer. This P layer IS is provided with a step. N''#J4, which is the first and last transistor of the previous stage, is formed in the second layer 13, and the first layer 14 and the first layer 13 are made of AI.
They are short-circuited by the (aluminum) electrode wiring layer 16. 1-Hiro pace electrode. On the other hand, in the subsequent transistor J, five transistors are ON,
$1 e I FIB #16m $784e1
8i#'i are formed protrudingly on the two layers 13, respectively.

Among these, a P+ layer 13 of the pace is provided protrudingly between N"MI 1 a a and N118-, and these 1 layers 11j4, 111. and P113 are short-circuited by the A! electrode wiring layer 19 e N ``On the AI 18t~18s, niobium and nitride electrodes 201~20s are formed, respectively.
Also w+H11Il, ~J ss and N”@ J J
, a pace electrode 21 is placed on each adjacent two layers 13.
1 to 214 are formed.

The emitter electrodes 201 to 20- and the Aj electrode wiring layer 1
Entrance electrode bodies 2j are commonly press-connected to 9 through a buffer plate 22. 24 is insulation M ('810.). On the other hand, a collector electrode body 27 is connected and fixed to the back surface of the N''M 11 via an Aj layer 25 and a buffer plate 26.The buffer plates 22 and 26 are both made of Mo (molybdenum) or W (tungsten). The emitter electrode body 23 and the collector electrode body 21 are both made of Cu (copper).

In this Darlington transistor, the resistances 3 and 4 between the gates and the pads of the transistors 1 and 2 utilize the lateral sheet resistances of the two layers 13 that serve as pads, respectively. Therefore, on the transistor 1 side, two layers 13 that serve as a pace are provided protrudingly between the wiring layer 1g and the wiring layer 1g, and these are short-circuited by the wiring layer 1# on the surface. The Shinkai engine has a short-circuit structure. Similarly, for the transistor L side, at the step part of the 2nd layer 130, the 1st layer 1 of the pace
An emitter short-circuit structure is formed in which N''f@14 of the ivy s and the ivy are short-circuited by the AI electrode wiring layer 15.

By the way, in this Darlington transistor, the transistor L in the latter stage has resistance 4 for pace and volume.
In addition, between the collector and emitter, the base region (2 layers 13) is the anode, the collector region (N] J and N+
A parasitic diode d having #11) as its cathode is equivalently connected with its cathode facing the collector side, as shown by the broken line in FIG.

Conventionally, when using a Darlington transistor with the above structure, one has to pay attention only to the resistance value of the resistor 4 and ignore its existence as a diode, or actively utilize the diode d. There are two methods,
In particular, as a method of actively utilizing the diode d, there is a method in which the area of the diode d is increased and the diode d is used as a high-speed freewheeling diode.

FIG. 4 shows a motor drive circuit for driving a DC motor using four Darlington transistors shown in FIG. The parasitic diodes D1 to D4 are equivalently connected between the collectors and the edges of the downstream transistors of the Darlington transistors Ql-Q4.
external high-speed freewheeling diodes connected in parallel to 4, M is the DC motor, L is the excitation winding, and E
is the power supply. The rotation of this DC motor M is controlled by adjusting each switching period and each phase of Darlington transistors Q1 to Q4. For example, in a forward rotation state, both Darlington transistors Ql and Q4 are turned on and the current 11 is 1→excitation i1ML→%
-/M→Transistor Q4, the energy flows in the direction shown by the concentrated arrow in the figure, and as a result, energy is stored in the excitation winding, and then when either transistor Q* or Qa is turned off, energy is stored in the excitation winding. The energy generated causes a current I, , 1. is excitation winding L → motor M → transistor Q
3→power supply E→transistor Qm, the currents flow in the directions of the dotted line arrows in the figure. ζHere, first of all, 9 layers of transistors.
.

Assuming that both Q4 are on and the DC motor M is rotating in the forward direction, when the zero-order transistor Qs turns off and transistor Q4 turns off, the large current that has been flowing up until now is caused by the parasitic diode a and the high-speed free Wheeling diode D
3 → 0 flowing through the parasitic diode d and the high-speed freewheeling diode D, When the transistor Q1 is turned on again, the current that immediately started flowing through the transistor Q1 does not flow toward the excitation winding, but flows through the diode d,, D, Flows as reverse recovery current. Therefore, these diodes dlpD
1, most of the voltage of the DC power supply E is applied to the transistor Q1 and a large current is generated. As a result, transistor Q1 is destroyed.

By the way, a high-speed diode is generally used as the external high-speed 7-way wheeling diode DI-D, and the recovery time of the diode is extremely short. However, the parasitic diode d in each transistor 91 to Q4
1 to d4 are the transistor collector saturation voltage VcI(s
It is designed to have a long lifetime due to improvements in at) and a high current amplification factor per area, and external high-speed freewheeling diodes D1 to D4.
The recovery time is longer under the conditions of the same area and the same reverse current value compared to the above.For this reason, when the reverse recovery current flows through the diode dlsDl, the diode DI recovers first, and then only the diode d1 has a reverse recovery time. A recovery current will flow. Which reverse recovery current operates in the same manner as the pace current when the transistor is turned on, and becomes an excessive reverse recovery current that is current amplified, and is converted into the collector current Ic in the Z vine region 1a4.1.
This has the disadvantage that current concentration occurs in the transistor Q1 and destroys the transistor Q1.

This invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a highly reliable semiconductor device that can prevent damage to short-circuited parts due to concentration of reverse recovery current flowing in parasitic diodes. There is a particular thing.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 5 is a plan view of the Hiroshima-Lington transistor, Fig. 6 is a sectional view taken along line OA-A' in Fig. 5, and Fig. 7 is a plan view of the above-mentioned Darlington transistor! 'nl, 4j is a P layer forming a pace formed on this N142. This one layer 43 is provided with a step. In the structure Z of the transistor 61 in FIG.
They are short-circuited by the electrode wiring layer 45.

46 is a pace electrode. On the other hand, the four breakdown layers 481°48m a4 serve as the edges of the transistor 62 in FIG.
8s 6484 are formed protrudingly on the two layers 43, respectively. On top of each of these 4g 1 to 484 are formed electrodes 49° to 494, and on top of the first layer 4J between these electrodes 491 to 4#4 are pace electrodes 50x to 50s. each formed. And N
"J14 II, the rightmost N1484 among ~484
In this case, a part of the area other than the area to which the vine electrode 494 is connected is connected to the first layer 43 serving as a pace via the AJ wiring layer 51.

One engine and evening electrode body 53 is commonly press-connected to the engine and evening electrodes 4g to 494 via a buffer plate 52. On the other hand, a collector electrode body 56 is connected and fixed to the back surface of the N''II 41 via an An layer 54 and a buffer plate 55. 5r is an insulating film (S!O,), and the buffer plates 52 and 55 are are both made of Mo and 11w, and
Both the electrode body 53 and the collector electrode body 56 are made of Cu.
It is formed of. In FIG. 5, reference numeral 10 indicates a wiring including an A wiring layer 51 and a space electrode 50 to SOS.

In this Darlington transistor, the resistance 63 between the lead and the back of the transistor 61 uses the sheet resistance of one layer 43 in FIG. 6, as in the conventional case. On the other hand, the resistance 64 of Transistory's pace, Koden, and Taseki is,
A buffer plate s is installed on the muno wiring layer 61 for pace/works Tsutaseki short circuit.
Since the electrode body 6S is not press-connected through the electrode 2, a sheet resistance of N+7148a is used. That is, between the collector and emitter of the transistor 62, there are the two layers 43, N142 and N"71 as described above.
A resistor 65 (that is, a resistor 64) is connected in series with a parasitic diode d between the resistor 4 and the resistor 64.

Therefore, even if the collector diodes are biased in the reverse direction and the parasitic diode d is biased in the forward direction, the reverse recovery current is limited by the resistor 65, preventing destruction of the emitter short circuit. It is possible.

Similarly, in the above embodiment, NPN) 5 transistor 6
1.62 describes a Darlington transistor, but is not limited to this (PNP Darlington transistor or single NPN) transistor or PNP) transistor, and may also be applied to a thyristor. is also possible. Furthermore, it goes without saying that the connection between the electrodes 491 to 494 and the emitter electrode body 53 is not limited to pressure contact, but may also be soldered.

As described above, according to this invention, there are multiple emies.

The emitter and rear electrode bodies commonly connected to the emitter and base electrodes are not connected to the shorted part of the emitter and base, but the structure utilizes the sheet resistance of the emitter and the base, which eliminates the large amount of reverse recovery caused by parasitic diodes. It is possible to limit the current and prevent damage at short-circuited parts of the emitter, ri, and base.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing a Darlington transistor, Figure 2 is a circuit diagram showing a Darlington transistor.
The figure is a cross-sectional view showing the semiconductor chip of the above transistor sealed in an envelope, FIG. 3 is a cross-sectional view showing the element structure of a conventional Darlington transistor, and FIG. Circuit diagram,
FIG. 5 is a plan view showing the element structure of a Darlington transistor according to an embodiment of the present invention, FIG. 6 is a sectional view taken along line A' in FIG. 5, and FIG. 7 is an equivalent circuit of the Darlington transistor. It is a diagram. 42...N single layer, 4J...P layer, 481-484.
...N4M<emitter), 4jt~494...emitter, electrode,',1. ．． <1.-AI wiring layer, SS-...
Engineering<, evening electrode body, 61. Jin! ...NPN) transistor, 63°54 (SS)...resistance, d...parasitic diode. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 3, 13s *56・Ll・178 Commissioner of the Patent Office Shima 1) Haruki Tono2, Name of invention semiconductor device 3, Person making amendment case- Related Patent Applicant (307) Tokyo Shibaura Electric Co., Ltd. 4, Agent 5, voluntarily amended the scope of the patent claims as shown in the attached document. a semiconductor body formed by forming a plurality of mesa-type second conductivity type layers on a plane of a first conductivity type layer having a plane; a metal electrode layer formed on each of the second conductivity type layers; and a metal electrode layer formed on each of the second conductivity type layers; A metal wiring layer connecting the first conductivity type layer to a part of a region other than the region connected to the metal electrode layer in at least one conductivity type layer among the second conductivity type layers. A semiconductor device comprising: a metal electrode body commonly connected to the plurality of metal electrode layers.

Claims (1)

[Claims] a semiconductor body formed by forming a plurality of second conductivity type layers on a plane of a first conductivity type layer having a plane; a metal electrode layer formed on each of the second conductivity type layers; and a metal electrode layer formed on each of the second conductivity type layers; In at least one conductivity type layer among the two conductivity type layers, a metal wiring layer connecting a part of a region other than the region connected to the metal electrode layer and the first conductivity type layer; A semiconductor device characterized by comprising a metal electrode body commonly connected to an electrode layer.