Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
1999-06-07
2001-04-17
Thomas, Tom (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
C257S133000, C257S146000, C257S339000, C257S370000
Reexamination Certificate
active
06218709
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device comprising an insulated gate bipolar transistor, and a semiconductor circuit using the same.
2. Description of the Prior Art
Power semiconductor devices represented by an insulated gate bipolar transistor are used to control various power equipments. In a control circuit using this insulated gate bipolar transistor, it is necessary to put out a collector current by placing a limitation in order to indirectly detect a state of a load R
L
connected with the collector and also improve oscillation stability of a feedback circuit by entering a signal from the collector to the feedback circuit.
In such cases, the prior art, as shown in
FIG. 6
, is devised to draw out a limited current or voltage through a resistor R
10
having high resistance from a control terminal
100
. In
FIG. 6
, Z
10
is a zener diode used to limit a voltage across the control terminal to less than a certain voltage and T
1
is the insulated gate bipolar transistor.
Recently, a semiconductor device comprising an insulated gate bipolar transistor T
1
as shown in
FIG. 7
has also been proposed.
The semiconductor device shown in
FIG. 7
uses a depletion type IGBT110 formed adjacent to the insulated gate bipolar transistor T
1
, in place of the resistor R
10
of high resistance, therethrough attempting to detect a collector voltage.
That is, in the depletion type IGBT110, an n-type impurity is diffused in a channel region to form an n
−
depletion region
111
, thus connecting a gate electrode
117
and an emitter electrode
119
, which are disposed above the n
−
depletion region
111
, by way of an opening formed on an insulating film
112
. Consequently, a circuit as shown in
FIG. 8
can thus be configured, in which the depletion type IGBT110 turns to be a state of ON even if a bias voltage between the gate electrode and the emitter electrode is zero (0), thereby drawing out the collector voltage or current.
However, there is a problem that the resistor of high resistance must be mounted separately in a circuitry of the prior art shown in
FIG. 6
because it is difficult to form the resistor of high resistance integrally with the insulated gate bipolar transistor on the semiconductor substrate. With the construction of
FIG. 7
, there also is a problem of complicated step because a diffusing step is further required to form the n
−
depletion region
111
.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an inexpensive semiconductor device which is integrally equipped with an insulated gate bipolar transistor and a terminal, capable of drawing out a limited current or voltage from a collector of the insulated gate bipolar transistor, on a semiconductor substrate, and a semiconductor circuit using the semiconductor device.
The present invention has been accomplished to attain the object described above.
The semiconductor device of the present invention is a semiconductor device comprising an insulated gate bipolar transistor provided with a gate formed through a gate insulator on an n-type semiconductor layer formed on a p-type semiconductor substrate, the semiconductor device further comprising a thyristor apart from the insulated gate bipolar transistor, the thyristor comprising a p-type region where a p-type impurity diffuses over a part of the n-type semiconductor layer, an n-type region where an n-type impurity diffuses over a part of said p-type region, an emitter electrode formed contiguously to the n-type region, a base electrode formed contiguously to the p-type region, and a collector electrode which is used in common with the insulated gate bipolar transistor.
In the semiconductor device thus configured, the p-type region and the n-type region can be formed concurrently with the p-type region and n-type region of the insulated gate bipolar transistor, respectively, and the limited voltage or current of the collector voltage or current of the insulated gate bipolar transistor can be drawn out from the emitter electrode.
According to the semiconductor device of the present invention, it is preferable that the second p-type region is formed in the n-type semiconductor layer by diffusing the p-type impurity between the insulated gate bipolar transistor and the thyristor to prevent the withstanding voltage characteristics from being degraded.
Furthermore, according to the semiconductor device of the present invention, in order to more effectively prevent degradation of withstanding voltage characteristics, it is preferable that the second p-type region is formed in the n-type semiconductor layer at both sides of the thyristor, and that an electrode made of the same material as that used for the gate is formed through an insulating film so as to cover between the p-type region and the second p-type region and a part of the p-type region and the second p-type region, thereby connecting the electrode and the emitter electrode.
Also the semiconductor circuit of the present invention is characterized by having the semiconductor device and a zener diode connected with the base electrode. With this construction, it is made possible to positively restrict a voltage of the base electrode to less than a yield voltage of the zener diode, thereby drawing out a voltage less than the base voltage from the emitter electrode.
Also according to the semiconductor circuit of the present invention, in order to draw out a current from the emitter electrode, it is preferable that different diode other than the zener diode is connected to the emitter electrode.
Furthermore, in the semiconductor circuit, it is made possible to connect a control circuit through the diode to the semiconductor device.
REFERENCES:
patent: 5162966 (1992-11-01), Fujihira
patent: 5631494 (1997-05-01), Sakurai et al.
patent: 63288064A (1987-05-01), None
K. Yoshida, et al., “A Self-Isolated Intelligent IGBT For Driving Ignition Coils”, Proceedings of 1998 International Symposium on Power Semiconductor Devices & Ics, Kyoto, pp. 105-108.
Hu Shouxiang
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Thomas Tom
LandOfFree
Semiconductor device and semiconductor circuit using the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device and semiconductor circuit using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device and semiconductor circuit using the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2497345