Semiconductor device
View Patent ↗An IGBT is disclosed which separated into two groups (first and second IGBT portions). First and second Zener diodes each composed of series-connected Zener diode parts are disposed so as to correspond to the groups respectively. Each of the first and second Zener diodes has an anode side connected to a corresponding one of first and second polysilicon gate wirings, and a cathode side connected to an emitter electrode. Temperature dependence of a forward voltage drop of each of first and second Zener diodes is used for reducing a gate voltage of a group rising in temperature to throttle a current flowing in the group and reduce the temperature of the group to thereby attain equalization of the temperature distribution in a surface of a chip. In this manner, it is possible to provide an MOS type semiconductor device in which equalization of the temperature distribution in a surface of a chip or among chips can be attained.
1. A semiconductor device comprising:
an MOS type switching element;
a diode composed of series-connected diode parts and having an anode side connected to a gate of the switching element, and a cathode side connected to an emitter or source of the switching element;
a gate pad; and
a resistor having one end connected to a junction of the gate of the switching element and the anode side of the diode, and the other end connected to the gate pad; wherein:
temperature dependence of a forward voltage drop of the diode reduces a voltage applied to the gate to thereby reduce current flowing in the switching element when the switching element rises in temperature.
2. A semiconductor device according to claim 1 , wherein
the gate of the switching element is separated into gate groups;
diodes each composed of series-connected diode parts are provided individually so as to correspond to the gate groups respectively;
each of the diodes has an anode side connected to a corresponding one of the gate groups, and a cathode side connected to the emitter or source of the switching element; resistors are provided so as to correspond to the diodes; and
each of the resistors has one end connected to the anode side of a corresponding one of the diodes, and the other end connected to the gate pad.
3. A semiconductor device according to claim 1 , wherein each diode is a Zener diode made of polysilicon.
4. A semiconductor device according to claim 1 , wherein each resistor is made of polysilicon.
5. A semiconductor device according to claim 1 , wherein a diode composed of series-connected diode parts is back-to-back connected to each diode composed of series-connected diode parts.
6. A semiconductor device according to claim 1 , wherein the switching element is an IGBT or an MOSFET.
7. A semiconductor device according to claim 1 , wherein the switching element is of a trench gate type or of a planar gate type.
8. A semiconductor device comprising:
a first semiconductor region of a first conductivity type;
a second semiconductor region of a second conductivity type disposed selectively on a surface of the first semiconductor region;
an insulating film disposed selectively on the second semiconductor region;
a Zener diode and a resistor formed on the insulating film;
a third semiconductor region of the first conductivity type disposed selectively on a surface of the second semiconductor region;
a gate electrode disposed, through a gate insulating film connected to the insulating film, in the second semiconductor region exposed while sandwiched between the third semiconductor region and the first semiconductor region;
a gate wiring disposed on the insulating film so as to be connected to the gate electrode;
a connection wiring which connects one end of the resistor to an anode side of the Zener diode and the gate wiring;
a gate pad connected to the other end of the resistor; and
a low potential side main electrode disposed so as to abut on a cathode side of the Zener diode and the third semiconductor region.
9. A semiconductor device according to claim 8 , wherein
the gate wiring is separated into gate wiring groups;
Zener diodes are provided individually so as to correspond to the gate wiring groups respectively;
each of the Zener diodes has an anode side connected to a corresponding one of the gate wiring groups, and a cathode side connected to the low potential side main electrode; resistors are provided so as to correspond to the gate wiring groups; and
each of the resistors has one end connected to a junction of the anode side of a corresponding one of the Zener diodes and a corresponding one of the gate wiring groups, and the other end connected to the gate pad.
10. A semiconductor device according to claim 8 , wherein a metal gate wiring is disposed on the gate wiring so that the metal gate wiring is connected to the gate wiring and connected to the connection wiring.
11. A semiconductor device according to claim 8 , wherein the connection wiring, the metal gate wiring and the low potential side main electrode are metal films made of the same material with the same thickness.